How To Choose The Right Turbo For Your Build

[@hpa101]

Building a fast car? Get EVERY course ever with $400 OFF the VIP package: hpcdmy.co/vipy13 Kickstart your turbocharged EFI Tuning knowledge. Get 50% OFF the EFI Fundamentals course: hpcdmy.co/offery13 0:00 - Introduction 1:00 - Many variables make it difficult to choose 1:36 - Effect of going too large 3:33 - Effect of going too small 4:06 - Boost pressure is largely irrelevant 8:03 - Lag vs boost threshold 12:15 - Aerodynamics 14:44 - Billet vs cast 18:42 - Turbine material 21:06 - Twin vs single scroll 22:46 - Letting your performance workshop choose 24:47 - Do your own research 28:34 - Use a turbo matching tool 29:10 - Reading compressor maps 33:30 - Mass airflow to power rough rule of thumb 35:41 - Garrett Boost Adviser demo 39:18- Borgwarner Match Bot demo | 7163 53:33- Borgwarner Match Bot demo | 8374 54:58 - Borgwarner Match Bot demo | 9180 1:01:30 - Validating performance 1:06:34 - Questions

[@theimprovementsguy8871]

Just started watching before i watch i like to test my quick summary knowledge. Ill say what i have learnt and see how it compairs. Smallest turbo possible for figure wanted

[@rileylilwell5201]

Man you guys put out some amazing vids👌🏼

[@danbailey9031]

It’s all about the ear flow

[@hpa101]

Just make sure you avoid getting an ear full - Taz.

[@PANTYEATR1]

This was a masterful class💪 thank you Andre and the HPA team for this. I must admit that i was always thinking i should figure out first, how much CFM of air any given engine could pump out at it's redline RPM, then find a turbo that could support double that CFM of air regardless of it would be used or not. I've owned the book "Maximum Boost" by Corky Bell since maybe 2002 and it's a great read and i never lend it out. That's where i learned most of my understanding on building turbo systems. I have a Dodge 2.4L, 4 banger that i plan on putting a GT3582R on. I'm hearing how it will take forever to get to it's boost threshold and that worries me a bit. I used to have a Turbonetics T3\T4 stage 2 on that engine and it made 336whp. The surge map portion was great and i feel that i understand it better. Greg @ car passion for a great lesson on the surge map that helped me as well. I have a question, when the exhaust manifold pressure is equal to or greater than the intake manifold boost pressure, will the vehicle feel like it hit a wall in the sense of not noticably accelerating or pulling as hard? Thanks

[@sexyfacenation]

Mate the exhaust pressure is almost always higher than manifold pressure in the vast majority of applications

[@jareddougherty8925]

@@sexyfacenation fake news

[@s4060]

First you want reliability. Second you want response. Third you want power. Forth you want the best. You want Borg Warner EFR.

[@carmello000jp]

Hmmmm you sure

[@Echelonperformance]

Speaking facts my EFR 8474 is 🔥. But going up from there really isn’t giving the flow I need

[@mr.c5217]

@@s4060 you want Garrett

[@Dodgevair]

Garrett's turbine exhaust flow charts.....I noticed that you can use Borg Warners turbo selector (Match Bot) to produce exhaust flow numbers (lbs/min) which can then be used in the charts. How do you correctly use that data along with the charts when choosing different A/R housings? I assume you would need to chose a housing where all the points fall below the lines(pressure ratio by turbine flow) in the chart? Or does something else factor in? thanks!

[@chippyjohn1]

Some of the questions you get, lol. I'm making a compound setup for an aircraft. dont see much talk of turbos and aircraft, all car related. first project is a pressure ratio of 12, the next is about 44.

[@byloyuripka9624]

probably because of what can be lost if the engine fails... imagine your family friving home and a plane falling on them cause some genius decided lycomings are not cool enough

[@chippyjohn1]

@@byloyuripka9624 Lycomings are not cool at all. Not a matter of being cool though, Lycomings are an outdated design from the 1930's. Modern car engines are far more advanced and better quality.

[@tbas8741]

That about boost pressure i tell people also and they laugh at me. on WRX's TD05 @ 10psi makes more power from 4500-6500 rpm on same 2.0L engine. than TD04 @ 15psi ~ 4500-6500rpm.

[@mr.c5217]

Hi Andre. I have a Dart 427 stage 2 cam with twin Garrett GTX3584RS with billet wheels and 3 inch downpipes 50 mm Turbosmart wastegates on C02. These are the biggest turbos and down pipes i can use on my car because of space restrictions. Do you think they are too small? I know these things will probably be at full boost by 3000 rpm.

[@aywall5905]

@1:08:50 I would like to also add that BIGGER turbos over standard size turbos that come with cars COULD also improve MPG because keeping your car out of boost esp while cruising in highway will improve MPG simply based on by tuning you could reduce the amount of fuel your car will need at (in my case as far as my EVO 9 goes) i hit full boost at 5200rpm with my 6875 PTE turbo so i wouldnt need all the fuel at 3000-4800 rpms that a stock size evo 9 turbo engine would need because of boost basically i wouldnt be boosting at such low rpms doesnt mean i wont be in boost if i hit the gas but my boost levels would be minimal 1-5psi as compared to oem size turbo which would be at about 10+ psi at those rpm levels.

[@NathanaelNaused]

I've been thinking this forever and wondering why More people don't aim for this solution on street driven cars that don't need to be in boost 24/7. Think something that makes enough power below 3k to not be a dog.

[@weduhpeople8504]

Borg Warner with the introduction of their EFR series has significantly changed the turbo charger’s performance by using gamma- ti turbine wheels being lighter which allows for a very fast transient response that helps get back on boost into the power and torque curve between shifts. Besides improved aerodynamics and lighter materials is the use of the very low friction ceramic ball bearings. They also engineered their chra for racing demands while also improving the seal using piston style rings and steel cages for the ball bearings. Not sure if they’re still using investment cast aluminum turbine housings which was really an improvement from the heavier cast iron turbine housing. The only con is the race grade chra is alot wider than the Garrett g series in equivalent turbo sizes. Garrett g series has improved performance using the M mar made for extreme high heat as well as improved aerodynamics and wheel size and shape of the fins.

[@phantomflame0658]

Yep with the EFR you can get away with essentially oversizing the turbo (or atleast going for a bit higher A/R ratio housing) due to the extremely efficient design meaning you still get great response and spool, and have a very strong top-end.

[@bmxriderforlife1234]

​@phantomflame0658 hmmm this might be useful for insanity build plan I have. K48 engine twincharged. Oversized underdriven superchargers positive displacement. Big turbos(for essentially a 2.1 cylinder)that'll flow enough and still make enough boost that it can be compounded by the super to make the final boost I want plus more. But flatplane crank helps spool, hotvee helps spooling as they both help scavenging. Twincharger can as well via pressure differences at intake vs exhaust back pressure, while also helping detonation thresholds with just a bit of controlled valve overlap but also helps spool and cooling. Was trying to decide on turbos. Not picky. Bur gonna need alot of wastegate and blowout valve. Oh while also keeping the two stages at peak effiency and sizing and choice for other effiency. Using ac powered water to air charge cooling set up for both packaging reasons and the ridiculous sub ambient intake temps. Density flow pressure all controllable. But also gonna help cooling the combustion chamber further. Cold intake air air pressure and density being pushed into exhaust manifold with hot fresh exhaust gasses. Heat expands air. More pressure. Better turbo spool. Also helps detonation. And already working out plans to help the head and valve train plus try and get full clearance back for the vtec timing adjustments.

[@Skirk84]

Going to the full race website to the exact place you did... There is no description, additional, results etc. There is only details and more information which is about 6 lines of text.

[@elmeesio]

“Not making power under 6k rpm….” that sounds about right, it’s my redline

[@hpa101]

You'd want to be making all your power under 6k in that case! 😅 - Taz.

[@HeidiFegles]

We all know for a turbo to reach full potential you need forged (quality made) rods, forged pistons, balanced assembly by a pro that actually knows what they are doing. And with more air we need fuel on demand any rpm at any time. Do not scrimp on fuel. Just rip the whole factory system out and replace with nice ethanol rated line I’d say min 25% bigger but realistically do the math on your pump and fuel usage at full throttle high demand and figure out how much pump you need and then at a 20% min over so the pump is working in its efficiency range and then a good tune. Tune doesn’t do shit unless your fuel does what you want with no limit. Or go cheap and have 2 Subaru motors now, both 2 cylinders sitting in the hood about 6” apart.

[@murk1352]

Billet wheels are a lot better than cast wheels for a bunch of reasons! Billet wheels are much stronger than cast wheels for one! Cast wheels can get tiny minute bubbles in the metal when being made & that in its self makes them weaker! Billet wheels are made a lot thinner than cast cause of how strong billet is & that means they’re a lot lighter, which means they can spool quicker & handle more of a beaten! They stay cooler than cast as well because they are thinner! Billet Vs. cast anything is always superior! Lastly because they’re made on a 5 axis milling machine, they can be made to be more aggressive & efficient!

[@crouleau13]

I have a 2005 Jeep grand Cherokee Limited with a 5.7 hemi never had a turbo what would be the right Turbo to buy for that? I appreciate any information you could give me you and have a great night.

[@kelvinleong915]

I experience something on crankcase pressure to high my turbo idle smoke,once I open a engine oil cap slightly smoke is disappear izzit too much back pressure

[@BoostWang]

Andre, If you had an auxiliary part that can force an increased velocity of exhaust gases in lower RPM's to drive the turbine ratio up higher in ways that is not naturally possible given a displacement, E.G, a Quick spool valve - it would normally plot the compressor into the surge zone correct? Since a WOT surge is having air mass being backed up against the compressor instead of flowing into the combustion chamber, can the surging be solved by changes to an engine's physical air mass capabilities E.G, cylinder head porting? Or is it simply futile to try to reap the benefits of a large compressor, if you had a method to manipulate the velocity of exhaust gases in lower RPM regions, because the surge zone on paper would actually dicate that it would surge on any engine?

[@stu1944]

Pretty awesome. Any real difference between water and oil cooled turbos

[@TheGinger1]

Glad I found the time to watch this. Great work

[@hpa101]

Hope you enjoyed it!

[@bowtiejake]

What would you recommend for a 388ci dart block with a cam with specs intake lift: .630 Exhaust lift: .630 Intake duration @.050": 247 Exhaust duration @.050": 253 LSA: 117 ADV: +6 Revving out to 7500rpm through a tr6060? Was looking a forced inductions 94/104mm 1.32ar s400 going to be a drag car

[@mattsnook1723]

I think you'd be pretty close. I run an S480 on a 5.3, a little less cam, a little more RPM, runs great.

[@bowtiejake]

@@mattsnook1723 yeah I was hoping for it to be efficient at around 1200rwhp range pushing 18-23psi of boost.

[@JacquesScott-h2i]

I have a 2007 Chevy Trailblazer with the 4200 Vortec (4.2L) 2wd inline 6ix... Which turbo you think I should get for my build. im tryin to go mildly appropriate with maybe a 400-450hp build. what all do you suggest? I just need my truck to sound good and drive nice. I love that mild chopping from the TBSS when its cammed, and I want to be able to do some kinda burnouts and improve my 0-60 and rolling 40 pulls... any advice???

[@coldiceEVO]

what about compound turbo selection? In the case of intercooled application, is the assumption of larger atmospheric turbo's flow rate divided by pressure ratio it produces get the volumetric flow for the higher pressure stage?

[@jacobhaussmann90]

I'm trying to figure out what size turbo for a sohc 4.0 inline 6 12 valve petrol engine ford falcon engine I'm thinking of using a ford Barra stock turbo GT3582R I think is what they are I'm only looking at making 300-350whp

[@turbo_brian]

Wait, would it be that different though? 15 psi is wayyyyyy below choke flow for both of those turbos so I would expect almost the same power between a gt30 and gt42 on a 2 liter 4g at least through the stock redline. Maybe if you're running 11k+ you'll start choking that gt30 hot side and see the power fall off where the gt42 is still holding strong. Obviously the low rpm stuff will be quite different as the gt42 will be much laggy. What you really want to do to determine if there's gonna be a big power difference is plot your compressor operating point vs engine rpm (lug line) on the respective compressor maps and calculate the power the compressors consume in both cases. Then, you would add your fuel mass to your air mass and have to estimate your egts based on important engine parameters (ignition timing, cam profiles, etc) and calculate the required expansion ratio required to generate the power your compressor needs. Then the comparison between those expansion ratios would tell you if one is going to significantly overpower the other. Or use advanced software that does it for you like gt power or ricardo wave etc. As that's wayyyy easier. To use your breathing analogy, if you exhale through a coffee straw versus a normal straw you'll feel a difference, but if you exhale through a 5" pvc pipe versus an 8" pvc pipe you won't feel a difference. Neither of those turbos should be wasted on so little boost. Edit: watched the whole video and see you went over boost advisor and boost bot. These are easier ways to do matching but make a ton of assumptions.

[@jesus_built_my_hotrod]

That was awesome

[@GroovesAndLands]

It has NOT been my experience that 15psi from two different turbochargers makes a "vast difference" in power, until you are in sizing territory that is extreme for the engine. Assuming both turbos are relatively efficient at producing suitable airflow for the boost pressure, both engines will make very similar power.... Again, unless there are WILD differences in EMAP. If one turbo makes the boost pressure with a MAP/EMAP of 0.75:1 and the other turbo does it with a MAP/EMAP of 3:1 - yes there will be a big power difference. But this would imply wildly different (and extreme) turbo sizes - neither of which is suitable for engine to begin with.

[@FastPaull]

The example he gave though, (3076 vs a GT4202) would be a vast difference at the same boost in regards to peak power at least.

[@DOO00K]

Perhaps not a vast difference in outright power, however, the same turbo with different AR can provide noticeable difference in performance on a car built for circuit racing. E.g. I found that a GTX2867R with .64AR provided superior performance over the entire rev range over a .86AR. The .86AR version could provide a higher peak output whereas the .64AR provided less lag and could provide more overall (not peak) power across a wider range of the RPM. This was on the 2.0l F4RT engine. So sizing considerations in this instance can make significant differences on track.

[@GroovesAndLands]

@@DOO00K No argument there. I'm just saying that 100kPa boost is gonna generate the same amount of torque (give or take a few fiddlebees) regardless of what turbo it's coming from - that is, unless the hot sides create WILDLY different EMAP

[@michaelgunning347]

@@GroovesAndLands a kinda no , but you might be thinking at the same rpm which should be ya , but the full engine rpm range has to be considered , and 1 major factor I feel is cam , fixed or variable

[@GreatDepressionRace]

If performance doesn’t change between turbo sizes, then something isn’t optimized. Even the idea that there is a “too big” turbo is subjective. Some people have a 40mm turbo on a 2.0L and some have an 86mm turbo on a 2.0L. Optimize it for your needs. There is no sweet spot where turbos are too small/big, or all the same. The world of hybrid T3/T4 turbos 20 years ago lead to people creating imbalanced turbos trying to cheat physics. T3 housings bored out for T4 turbine wheels were awful and so were huge compressor wheels packed into factory compressor covers. They are still bad today but people don’t want to change fitment.

[@NeutronPerformance]

Andre, I have a question maybe you can help shine some light on it with some of your knowledge. I have a k24a2 that's got a fully built bottom end utilizing a stock top end except it has springs and retainers. It's a street build so I wanted something that can drive nicely on the street and be reliable. It has stock cams etc. Only thing done to the cylinder head is titanium springs and retainers. It has a precision 6875 T4 .96 ar housing. The car made 676whp on the dyno at 29psi. Ok Here is my problem haha... my friend has a similar build everything basically the same except that he has a smaller turbo. He has a pulsar 3584r T4 and he made 760whp at 29psi, same psi that I told my tuner to leave it at. We both have the same tuner as well. We are talking about 80hp difference and he has a smaller turbo then me. My tuner told me that at 29psi, my precision 6875 is not where it shines and would require more boost somewhere along the line of 38+ psi where it starts to really rock. My question is, is it possible that with a larger turbo like my 6875 at 29psi, its not efficient and a smaller turbo would be more efficient in this psi range and have you ever seen anything like that before as a tuner. I hope i explained everything properly. Idk man i just find it very hard to believe how my buddy with a very similar build as mine is making 80hp more then my setup using a smaller turbo.

[@hpa101]

I have replied to your email and Facebook message - Taz.

[@boandersson5947]

Why not use a small one to get preasure at low rpm and then switch over to big boy?

[@djmurria]

A compound turbo set up would work perfect for if u need power everywhere. But complexity and cost is the main reason ppl don't do it. Exhaust feeding small turbo-small turbo exhaust feeding big turbo(wastegates before small turbo plumbed to big turbo turbine inlet)-big turbo exhaust to downpipe. Big turbo compressor outlet to small turbo comp inlet-small turbo comp outlet to throttle body.

[@djmurria]

Dream build is superlite slc or gtr w/ vortec 4200 or bmw n54(I think) or any I6 really with compound turbo like a 58-62mm for small turbo and 72-78mm for big turbo. Think that'd make for a setup that u could get on at any rpm and get moving good

[@bingoberra18]

The Honda K24 can be pretty high flowing as standard or slightly modified. I feel like turbo matching is difficult when we are talking about lower horsepower figures since you are basically scraping along the bottom of all compressor maps and falling out of them at higher rpms. Is there any good turbo for the K24 as a low powered ~350 crank hp engine at about 7-8psi (high flow at low PR)? Looking at many compressor maps they seem to be aimed at pretty poorly flowing engines making something in the region of 85hp/l...

[@cleveland2286]

That's unfortunately just how turbochargers work. Some turbos can handle a wider range of airflow like the s366 compared to similarly sized turbos (GT45, G35-1050 less so), but that's up to you to decide. Personally I think a larger compressor and proportionally smaller turbine and A/R might be what you're looking for. Something like a T3/T4 or maybe just a straight T3 with a 0.6X A/R housing. High revving and small displacement engines don't get the luxury of having a wide range of boost.

[@bingoberra18]

​@@cleveland2286 The problem is not width in my opinion. I get that you cannot make a turbo that is both efficient at high and low pressures. I think the problem is that there is not enough demand for my particular requirement so there are no turbos focusing on high flow-low pressure efficiency. A bigger compressor on a small turbine is not what I am after. I want the compressor itself to be efficient at lower boost while flowing enough for the engine requirements. No OEM turbo engine is flowing as well as a Honda K-series, so there has never really been a point for manufacturers to cater to this request. Unless for very low hp OEM engines. For example Saab 2.0t was a low pressure turbo engine doing 150hp stock. While an SR20 or 4G63 pretty much does 150hp NA. Now the K-series are basically flowing as much air NA as a SR20 or 4G63 are doing with a turbo...

[@cleveland2286]

@@bingoberra18 You can absolutely have a turbocharger that is efficient at both high and low pressure ratios. The issue is how much air mass you want at those pressure ratios. The EFR 7163 is very efficient both at a pressure ratio of 1.2 and 3.8 The difference is at 3.8 its flowing 7x the air in mass. The pressure ratio refers to the pressure at the outlet of the compressor compared to the inlet. Its impossible to have a turbocharger that flows more air mass (as the engine climbs rpm) at the same pressure without changing the volume. No turbo can do that. Ideal gas law. Smaller turbos do it better because of square cube law. Unless you want to slap two K04-2075s on your motor or some kind of VGT, its unlikely you will ever find the turbo you are looking for.

[@induetime]

In the thumb nail picture it shows the turbo inlet tube not connected to the compressor cover. I've seen this on a few dedicated drag cars. Can you speak on why this is done & any advantages?

[@synapticbit]

My **GUESS** is that the idea is to delivery air from outside the engine compartment (presumably cooler air) to the turbo inlet while allowing the engine to heave and move during acceleration…

[@R.B_B]

Why in some big turbo the air intake pipe is offset from the compressor?

[@marcusfrostenson9959]

Can you overcome smaller turbo restrictions if you run a large external wastegate?

[@horacecunningham7832]

Yes but it's not the right way to do it

[@marcusfrostenson9959]

@@horacecunningham7832 well if it works and its not prone to problems, it seems like a win win.

[@scootbmx01]

depends what those restrictions are, you need to remember the point of a wastegate is to vent excess exhaust gas to maintain a given turbine shaft speed and thus boost pressure for your application. If you are tapped out on the turbo and physically cannot spin it any faster or youre that far out of the efficiency map that you cannot make more power per psi than an external gate is NOT going to do anything.

[@GroovesAndLands]

I don't see why not. This would make an interesting test. Build a hybrid turbo with an 800hp capable compressor - with a 0.63 T3 exhaust side. Install 3 or 4 big external wastegates that have enough flow to accomodate 800hp worth of exhaust. Why wouldn't this allow for super fast spool on account of the tiny turbine, but no uneccessary backpressure up top? Obviously you'd be wastegating 90% of the exhaust...

[@ho6b9s]

@@GroovesAndLands I think the main issue with this type of setup is trying to get the turbine to spin at the speed necessary to drive that 800hp worth of compressor. The more exhaust that gets wastegated, the less drives the turbine. It may take that full exhaust manifold pressure to drive the turbine hard enough (if it can even handle the speed). Still, very interesting theory I'd like to see explored. .63 housing on a 35R size turbo with like a 60mm wastegate doesn't seem particularly abnormal to fit (depending on the chassis), and you could neck it down to compare to a 40mm gate.

[@adrianochiro4299]

I have a 20B rotary half bridge engine with 9.0:1 lighted rotors factory intake and S5 exhaust housings. I am struggling to know how to select a turbo for 900hp flywheel with minimal lag boost threshold. Lots of information on piston engines but not much around rotary engines.

[@oliverscorsim]

Fellow rotorhead my rule of thumb has always been pick a turbine that flows 25% more air than a piston engine. So power basicly. For compressors keep in mind wankels use about 15% more air than a piston engine..

[@adrianochiro4299]

@@oliverscorsim how much air would the 20B be pumping out per second? Garret and BW gives this curve on their turbo rear housings but I don’t know what the 20B needs before back pressure becomes to high.

[@oliverscorsim]

@@adrianochiro4299 yeah but to find that what kinda ports,turbo,fuel? This isnt exact as you need port timing to get dead on. But that being said a stock 4 port 13b uses about the same curve and flow as a 2.6 inline6 same for pulses give or take.for a 20b a decent geuss na would be 3.9l inline 9 so a good turbo for a barra would be a good comparison even if the pulse timing is off. So a gt30 is about as small as it wouldnt mind ie back pressure gets crazy but would be similar to an oem application in the spool sense.

[@oliverscorsim]

Generally compressor flow vs hp works out to lbs/min x 10 = hp just keep inmind the exhaust has tomove that plus the fuel component and heat so go up onesize on turbinehousing.

[@anthonygonsalves9557]

Can work with the engine specfation

[@TheNatepate]

I thought billet wheels was lighter than cast and I thought compare to gt series the gtx gen 2 was way more efficient

[@geobigntall3830]

What is a good set up for street for a first budget set up, I have a 2011 Hyundai Genesis. I want to make 400 whp , maybe 350 automatic/ manual shift 3800 2.0T ..tired of bully F150s riding my bumper at 90 mph.

[@hpa101]

I am not familiar with your specific car sorry but for a car that has been around a while you should be able to find some off the shelf kits and see what they address to make such power levels as well as what they include. From there you can buy the parts that make up the kit one at a time when and as you see a deal to do it the cheapest way possible. The quickest and most simple way is to just buy such kits, again noting this is assuming they are ones that have been well tested and reviewed over the years, as not all kits are made equal! Don't forget the engine management side of things and to make sure you double double check the limits of your driveline etc. No point making 400whp if your transmission is likely to grenade at anything over 360whp for example - Taz.

[@FahimRazzaque]

This guy looks like Christian Bale 😂😂

[@bobbondarul7448]

Nice. Is posible to obtain over 250hp from a 1.6 tdi engine ? And what is the turbine thats optimal for that job? Thank you

[@printf_helloworld.]

A GBC22 would do a great job

[@bobbondarul7448]

@@printf_helloworld. Thank you

[@alexkwok7529]

For street use, any different between ball bearing vs General bearing. My engine is RB26 Thanks

[@Kj16V]

In my experience, not enough of a difference to be worth the extra money for bb. No major effect on boost threshold. Never really had a chance to compare lag, but if there is an improvement, it's only small. IMO, if you're on a budget and you have the choice between identical BB and JB turbos, choose the JB and use that 500 quid you saved elsewhere on your project 😄

[@moiseiboianov7450]

hi im looking for advise i have a BMW e46 with the engine M52B28TU and im looking for a turbo ist will be my dayly car so the target is 350-400HP with 0.7-1.0 bar engine is stock and i know its good till 450hp in the future i may upgrade the engine to 500-600hp but now im asking for advice whitch turbo with what A/R is better 0.63 or 0.82 for 2.8 Liter i like to spool from 3000-3500 RPM im looking for a garett now thank you

[@AshLongie]

U want a promod 88

[@HomeMadeBoards]

Well I was just about to blow an rb30 up to find out....guess I could watch the video instead 🤷🏻‍♂️

[@bigjdm5460]

LOL!! bro, chill

[@dreednlb]

32:58 Forgot to share your screen here.

[@Gidanski]

So what about a High comp/large turbo E85 build? Will some of the downsides of the larger running a larger than recommended turbocharger (Eg something like a GTX3584 or G35-900 on a 2l) be offset by the higher EGT's (Comp) and more mass flow of running E85 compared to regular petrol?

[@RwP223]

It would be a dog until late in the rpm range. High compression high boost would be fun but a huge turbo would produce extreme cylinder pressures. Have you looked into using small nitrous shots to help spool oversized turbos? This way you can build the engine to handle the huge turbo while patching up your low end torque.

[@Gidanski]

@@RwP223 With what I was thinking it wouldn't actually be that bad as a car to drive from stoplight to stoplight, think mildly tuned NA car that if poked will try to rip your face off. Also Nitrous on a actually 100% legitimate legal street car isn't a thing where I live, and if you're racing on a track day chances are you can keep the engine up where the turbo stays somewhat responsive anyway.

[@djmurria]

Could try methanol for racing and ethanol on the street. I know for sure all the extra methanol could get a somewhat oversized turbo spooled up and can handle high comp and boost

[@TheSol115]

what about to select a wastegate . ?

[@hpa101]

Give a few of your trusted parts suppliers or the likes of Turbosmart a call, answer their questions which will let them know the details they need to know regarding your build, and they will advise. From there you can dig around to verify your specific option/s - Taz.

[@funkyjunky6574]

Guys can you help me build a reliable A16LET inline 4 which everbody says is a shit engine i just want to get 250 hp and to be a solid reliable build

[@G33.DEVELOPMENTS]

@funkyjunky6574 use a k04/k06 hybrid with the courtnay sport z16leh conversion manifold allows you to use the astra vxr core but keeps the exhaust ect a oe fit makes 306bhp :)

[@md-run]

Generally less laggy turbos have less boost threshold. Boost threshold and lag are the same thing IMO

[@sexyfacenation]

Nah mate, not the same. Perhaps somewhat related, but not the same

[@md-run]

@@sexyfacenation but a less laggy turbo will make peak boost earlier 🤭

[@sexyfacenation]

@@md-run yep, maybe.

[@ABusFullaJewz]

I believe his point was to draw a distinction between surge/boost threshold as the minimum flow to begin building boost under steady state conditions and lag as the effects of rotational inertia on boost responsiveness. By that definition they are two very different concepts

[@thomasnwilcox4537]

If you want to run a Turbocharger a supercharger how to mach for maximum horsepower

[@christopherchristiaan3788]

Bmw 1 series 1.6l 2006

[@allthehandlesweretaken]

but what if you measured boost pressure at the manifoild opossed to the turbo itself? wouldn't the same boost pressure from two diffrent turbos still mean the same airflow? since the volume of the manifoild is constant

[@jcadlols]

That would be correct if the temperature was the same. A less efficient turbo will have a hotter charge. Gas gets bigger (less dense) when it’s hotter. Also, more exhaust back pressure will increase pumping losses and further reduce power.

[@dogmoo]

The biggest one that fits. /

[@DrSpanky]

How much of a difference does a twin scroll make?

[@drewdavis239]

A LOT , especially on big power builds. Makes a big turbo act much smaller, 500 to 1000 rpm sooner spool vs a open manifold on 4 and 6 cylinder cars I have run them on

[@DrSpanky]

@@drewdavis239 I have a HX35w on a 2.4l diesel and it's sloooooooow. Has the twin scroll turbo but open manifold at the moment.

[@bigjdm5460]

@@drewdavis239 making power 500 to 1,000 rpm sooner . Any drastic difference on running out of rpms at higher rpm’s?

[@gaboonviper85]

Think you could go into greater detail on diesel turbo selection? I tried making an account on garret to use their turbo selection guide but seems you need to be a dealer or something. I'm currently working on a project 2011 bmw 335d and have a custom t3 turbo manifold made by diesel pump uk..... ill be using their quick spool valve as well but my goal is 600hp to the tires with the fastest spool I can get though I'm aware I'll have a higher boost threshold but I'd still like the best option I can but finding 3.0 diesel results is proving almost impossible.

[@renebarun1904]

Borg Warner EFR are out of stock

[@liammartin8773]

moa eair

[@gammalight1312]

CFM

[@sexyfacenation]

?

[@gammalight1312]

@sexy_face CFM (air flow) restrictions post turbo, artificially raise boost pressure. Boost pressure reflects CFM efficiency. CFM > PSI

[@sexyfacenation]

@@gammalight1312 cool. That makes more sense than a 3 letter comment!

[@2511jeremy]

Mad manifold air density thats the most important 15psi of hot air is alot less air then 15psi of cold air