Easy Basic Turbo Sizing Tips For Dummies | Carbureted LS | Blow Through Holley Carb |

[@oldschoolcars3318]

Thank you for your video. While there are some good ground rules here, you totally avoided the math and yes, you would have to be a dummy to buy a Turbo without doing the math and understanding your purpose in the build and the math associated with the rest of the engine. Your 1PSI for 10% HP idea simply does not wash as that relationship varies with ambient temp, altitude, and humidity. At Sea level Ambient air pressure is 14.7 PSI so 1 lb of boost will only actually give you 1/14.7 or 6.8% theoretical increase in HP IF your volumetric efficiency remains static with RPM increase. And while it would be nice to think the relationship between horsepower and boost is linear, it is not: there is decay as you raise temperature and as volumetric efficiency of the engine as an air pump fades as exhaust pressure builds. If you pick your RPM limit and your worst case volumetric efficiency and you know your displacement it is easy to calculate the CFM of air you are pumping through the engine. If you multiply that CFM by roughly 6.8% for every pound of boost you think you want to run you can quickly come up with the total flow you need through the intake and exhaust and then look at the turbo specs for max flow. If your max calculated flow is 80 to 90 % of the max flow for the turbo, you likely have a good match. My advice is to do the math cause going by a port size is not going to help you pick a turbo in your mathematical sweet spot. This is especially true when boosting below 3 liters in fours and sixes where the numbers get smaller and a mistake can see you with a limited top end or with some serious lag and sluggish build.

[@rifleman7313]

Great video, very informative. My preferred setup is an ultra responsive forced induction system but lower maximum rpm for trucks. Either with a correctly sized turbo or a positive displacement. Although I am new to this concept so I do not know very much, as of yet.

[@mariobarbosa3095]

This video needs more likes . Great description

[@NightWrencher]

Thank you! I appreciate it!

[@Hello_its_me_mario]

Made 630 on this exact turbo on a stock honda k24 at 23psi

[@NightWrencher]

Very nice. I Think that GT 35s are good up to 600 reliably

[@DylanMorehouse]

This was very very well explained and answered literally all of my questions thank you so much!!!

[@anotherdedchannel]

10psi on any turbo is 10psi on the displacement of your engine. What you were trying to say is a smaller turbo has to spin faster to make the same psi as a big turbo. Thus choking it off eventually. You said it yourself, the pressure is on your engine and it's displacement doesn't change so 10psi is indeed 10psi.

[@lerabidheavy7437]

So about the horsepower numbers, usually you are able to calculate max hp based on CFM flow times 1.6 which usually seems to make sense as said larger v8 can make 400hp and would flow say 350cfm then to get 350 CFM out a 2.4 liter the thing would have to spin about twice as fast to get the same airflow.

[@NightWrencher]

Thats right, its all airflow and basic math for the most part. For a turbo, once you know how much power you want to make, the rest is just a little bit of math

[@_illtal]

10 psi is 10 psi, the airflow is different. This is what you mean. This can be seen on the compressor maps. If you go into choke, where if you increase boost pressure, there will be no extra flow.

[@cheeseburguhgaming9581]

i see thank you for the education now i will know to choose the correct turbo

[@tonypace2009]

Nice looking forward to seeing it installed.

[@NightWrencher]

You and me both 🤣 the hard part will be all the plumbing. After that, tons of blow through carb videos

[@tonypace2009]

@@NightWrencher also curious on how much intake manifold design will effect turbo setup?

[@NightWrencher]

Me too actually. I havnt found an answer yet but I might be able to get away with just using a tall open plenum spacer.

[@Chris-bn1bn]

Good explanation, but what about a large turbo being fed by all 8 cylinders. A few really fast cars run this setup, similar to a Procharger setup.

[@NightWrencher]

I'm assuming you mean like a single turbo set up on a V8 engine? Thats what mine is, making over 600hp

[@matthewvarnam4302]

I'm wanting to do a big single turbo on a stock LS 5.3.....I'm wanting to make a 1,000 hp to the tires.....but I'm wanting a little more room to play with on the turbo to grow and have a little more hp later on....after I get the turbo I'll do a cam and intake swap to make more hp....I'm wanting the turbo to spool as fast as possible but still have the top end power........could you point me to the right direction on Maybe 2 different types of turbos to choose from.....I'm really wanting to go all out on this combo I want to start racing this thing one day after I get the bugs worked out and get used to turbo tuning and all that stuff.....I'm no good at math and I'm turbo dumb so I have a lot of Learning to do.

[@TheApexRabbit]

thanks mate really nicely explained. chears

[@arthurianwilliams5045]

Good info... But need more...oil pan...what kit you used...

[@NightWrencher]

For the oil drain? I always weld a -10 AN bung to a steel oil pan or have a bung welded on by someone else if its aluminum. After that I make my own AN line for the drain

[@tburda823]

Thank you for this great video. A question that maybe anyone can answer, the power increase of 10%, is it (I believe I'm asking this correctly) exponential, or linear? I.e., 1lb/10%=110, 2lb/20%=120, 3lb/30%=130 or does it grow from the baseline, 1lb: +10% of 100=110, 2lb: +10% of 110(121), 3lb: +10% of 121(132)...etc Hope that makes sense. Or does it really not matter because it's just a rule of thumb? Obviously using 100 HP as a baseline makes the difference minimal, but at 500/600 HP that change would be significant.

[@NightWrencher]

Its actually more like 7% and it is linear so at about 15lbs which is 1 atmosphere you would double the horsepower. My truck made 220whp with the 4.8. At 15lbs is made 440hp and at 21lbs it made 530. With a 500hp engine at 15lbs you should be at 1000hp.

[@tburda823]

@@NightWrencher Thanks for the reply! I started studying turbo technology about 20 years ago, but got out of motorsports as a hobby and recently started getting back into it. Enjoying re-learning all these things especially how far technology has come in that time. 1000HP is the 500HP of 20 years ago.

[@NightWrencher]

Exactly but its still deceptively hard to do. A lot of people claim that they make 1000hp when they really don't or only did it once on the dyno. Things like transmissions, differentials, fuel systems, etc, take a huge beating trying to make that 4 digit mark but starting with an engine with more displacement or more base hp does make the job a little easier

[@gforce_117]

Too add to what NightWrencher said, a little formula you can use is your (ambient pressure + psi of boost) / ambient pressure. This will give you a multiplier of how many "atmospheres" your engine is being exposed to. Take the multiplier times your N/A output to get your rough estimate. With a proper turbo and good fuel/tune you should make that power.

[@jaygill3037]

Am dummy, was informative. Subbed.

[@NightWrencher]

Lol, thanks man, appreciate it!

[@martinrudolph6090]

Can you help me size a turbo for a 1992 Ford 460 c I. Motor in a motorhome,I'm just looking for lower rpm power to pull it along easier?

[@jasonquarsingh3002]

You missing a crucial point, flow rate, measured in weight / unit time lb/min

[@NightWrencher]

Youre right but the average person new to turbos wont understand that nor do they want to. There are several turbos designed for the same hp rating but they all get there at different speeds. Once you know what doesnt work, its much easier to start figuring what you actually need. For example. I'm running a chineese 78/75 right now. I know what it can do and what it cant. When I upgrade to a brand name turbo I'll have a really good idea of what to go with.

[@bobbondarul7448]

Nice. Please recommend me a turbo that will make 300hp on a 1.6 tdi CR with dpf Thank you

[@NightWrencher]

It depends on how the engine power curve performs but something similar to a gt28 or TD05 should work.

[@rustypotatos]

Wow thank you

[@NightWrencher]

Hope it helps!

[@marcustrue1213]

What about a single cylinder 200cc yamahauler 1984 three wheeler??? Also it makes roughly 12 hp

[@julianfreto1666]

You didn't mention a waste gate; the problem you mention of too much exhaust gasses than the turbo can handle is alleviated by a waste gate which bypasses the turbo and sends the gasses down the exhaust pipe directly, right??

[@NightWrencher]

Yes and no. If the turbo is too small, the waste gate will be open more often. You can install a bigger wastegate or even a 2nd waste gate to prevent over loading the turbo so essentially you'll get max boost at a lower RPM. Your turbo will wear out faster, your waste gates will wear out faster and if one of those have an Issue, you're going to haver serious problems. If you want almost instantaneous boost, get a supercharger. Turbos are for max top end and super chargers are go all around performance but they dont put out as much power as a good size turbo does.

[@danieltomaino3697]

yes

[@oxidationdondetailing7621]

My engine is a stock 1.5l that has a rpm of 6000... What size turbo would be best....i want it to produce power rite away and have a pulling affect as it increase speed

[@NightWrencher]

First place to start is figure out how much power your engine makes stock. If it makes 100hp. At 15lbs of boost it will make 200. 15lbs is about as far as you can go on stock internals of most engines. You want a turbo that makes about 250% of what your engine makes now. After you figure out what turbos are available, narrow it down by exhaust housing, smaller is more response but can choke the engine if RPM get too high.

[@oxidationdondetailing7621]

@@NightWrencher my engine make 135hp at 10lbs of boost it can make 270hp but can the engine handle it.....its a 1.5 earthdreams engine

[@NightWrencher]

@oxidationdondetailing7621 "boost" is just a measurment on restriction against your air pump "engine". 10psi is not 10psi of air. Its 10psi of pressure against your intake valves. 0 psi is 1 atmosphere(1 bar) 14.7lbs of boost pressure is 2 atmosphere (2 bar). 2 atmosphere is 2x the air of 0psi. So if your engine makes 135hp, on 14.7psi it should make 270hp provided nothing else changes. Now, thats 270bhp. After drivetrain losses youll probably be sitting at 220whp. Most stock engines will hold 2 bar of boost pressure IF the you have 1) proper spark timing 2) proper air fuel ratios 3) correct heat range spark plugs 4) enough ring gap in the pistons. If any of those are not set correctly, your engine will probably blow up at 5lbs.

[@NightWrencher]

@oxidationdondetailing7621 as a point of refference, heres my last dyno day kzbin.info/www/bejne/mJ2oe4qnZZWra6M

[@oxidationdondetailing7621]

@@NightWrencher ohk thank you

[@frankdatank7751]

Blowthrough carb !!!!!!

[@NightWrencher]

Hopefully soon!

[@Bbbbad724]

On a 416 ci Ford FE I am considering a pair of these 33582s . Is this big enough to run as a pair with an intercooler. would a pair of these run 10-12 lbs and 850 hp? The NA power would be 510 hp. Do I need bigger turbos?

[@NightWrencher]

If you're thinking the 416 will make 510 at the flywheel then these turbos should be able to feed that motor just fine. If your goal is 850 at the rear wheels then these turbos will still get you there but they will almost be maxed out

[@Bbbbad724]

Thank you. Is there a pair of turbos between the 35 and the 45. That would be clean on a 2 four intake. I would like to have the boost / temp relationship in the right direction. The BBM tunnel wedge has a very good shot at the bowl.

[@Bbbbad724]

@@NightWrencher I s there a pair that you would recommend better? I have heard of the VS 7582s but what do think?

[@Bbbbad724]

⁠@@NightWrencherWould a Pair of GT45s better on a 416 ci around 510 na, 900 hp boosted.

[@NightWrencher]

Hey bud, I had forgotten to reply last time. Two GT45s would not spool very well at all. 2 78/75s would spool a lot faster and would feed up to about 1300whp. VS racing sells different turbos in between the gt35 and gt45 that would work well and still feed enough air for what you need, the only drawback is that they cost much more than a pair of ebay 78/75s would

[@1stzard]

I still don't know what size to get

[@NightWrencher]

Figure our how much horsepower you want to make at the crank. Then pick the turbo that makes that power.

[@TheProchargedmopar]

👍💪

[@NightWrencher]

Soon I'll be as fast as you 💪

[@TheProchargedmopar]

@@NightWrencher That will be easy, Mines back on blocks! 😝

[@NightWrencher]

Lets see where we are at in 6 months when my turbo is in!

[@gabrielbsalvatori]

said a lot of things and explained nothing.