No Body Remembers This Forgotten Draw Through Turbocharger VS Blow Thru Turbo | Carbureted Turbo LS

[@NightWrencher]

What do you guys think is the better set up?

[@jaydubb71]

Boost baby!

[@joeyleinart8354]

Blow thru I would say since most use this platform. There is a reason they abandoned the draw thru system

[@NightWrencher]

Thats always my go to logic as well.

[@jaydubb71]

@@joeyleinart8354 blow thru all the way

[@2strokefather863]

It all depends, if u have a small 4cyl an only want to make abit extra power then a draw through system is the way to go because it’s not like you’ll ever make more then 200hp with a small engine anyways an plus it’s way easier to tune like u said but if u have a bigger engine an plane on making more then 200hp then a blow through set up is what u will need. Draw = abit extra power, blow through = big hp engine

[@DoctorMotorcycle]

Nobody remembers the Draw-thru? lol, I make a living building draw-thru turbo setups, and I'm not the only one either Carburetor height in reference to the intake manifold doesn't have an effect on the vacuum signal. My draw-thru turbo bikes (especially the v-twins) cold start like stock bikes, and only the small inline fours (42mm carb on a 550cc) with big carbs have trouble with cold-starts, and you can get around that with a flick of the accelerator pump. Draw-thru setups run much cooler charge temps, and it's one of the reasons they're known for being more cold blooded than blow-through's; the intake manifold takes a while to get up to temp, because it's being cooled by the fuel passing through the coldside of the turbo setup. Which is the draw-thru's main advantage; when you run alcohol/ethanol fuels, the intake ices over, and you don't even need an intercooler. And let's not downplay just how simple draw-thru's on a motorcycle are; No fuel pump to fail, no fuel pressure regulator, no dicking around with pitot tubes to get it to transition into boost right, blow-off-valves aren't necessary, the list goes on. Straight out of the gate you save yourself $500 and the packaging of all the extra stuff on the bike. If I'm going to go through with putting a fuel pump, FPR and all that junk on the bike I'm going to put an ECU and throttle bodies on it and make it EFI (I'm actually doing that to a build right now).

[@NightWrencher]

I can't speak for motorcycles because they are their own deal so you're probably 100% right. On a drawthrough V8 its a whole different animal. Draw through has a lot of advanges like you said, but for all out performance and drivability, blowthrough is the way to go. I'm not even sure if blow through is a thing on motorcycles 🤷‍♂️

[@jaliennation9169]

i had a 45 dcoe into an ebay t3/t4 turbo on my 280z. carb and turbo were inline, like on a beetle setup, but was installed below intake manifolds. is that a problem? other than that, the only problem seemed to be that the turbo didn't have a carbon seal. sucked out oil mostly on idle and left a long plume of smoke on take-off. are there carbon seals for ebay turbo's?

[@NightWrencher]

As far as I know, the cheap turbos dont have any carbon seals or retrofit kits. I would recommend finding a way to convert to blow through if possible. Eventually it will ruin the turbo or engine if you keep going through so much oil through the intake. Remember, oil vapor is combustible and can cause detonation.

[@jaliennation9169]

yea, i took it off a while ago. just single carb now@@NightWrencher

[@jimbojimson]

@@NightWrencherSame thing this guy said, from the old timers I've talked to who ran draw through setups in the 80s and 90s, the thing they kept harping on was the fact that the draw through cools the charge more than a blow through. In the video you said the blow through cools the charge more, but this seems to be completely backwards of what most people have witnessed with their own intake air temps.

[@jaydubb71]

I'm glad someone put this video out. I've known this info for years. Especially since I've been on a particular turbo forum for years and years. For someone who can't affore an LS, Gen 3 Hemi or a Coyote, a blow thru small block/big block Chevy/Ford or Mopar with properly sized turbo can make very impressive power without breaking the bank. More folks should research this since they say boost is so prohibitively expensive. The return for the dollar when comparing budget turbo combos vs building NA combos is staggering. Imagine 600whp from a blowthru SBC 350 vs 500whp from a built 400+ SBC 400. Just the money spent on the stroker kit for the 400 SBC (go find a cheap junkyard 400 SBC in the junk yard... I'll wait...). Or a 383 SBC built to the hilt. By the time you buy the stroker kit, have a machine shop do all the machining and assembly, you might make 500whp on 93 octane. A junkyard 350 with gapped rings and decent heads/cam combo (no you don't need AFR heads and a big choppity chop chop cam). You can make 600+ whp and have a great time. For way less than that built forged bottom end 383. And if that junkyard 350 breaks, just get another one. Even if it's a basic 355 rebuild.

[@NightWrencher]

Exactly right, and usually, the second one doesn't breK because by then you've dialed in the tune 👍

[@Thumper68]

Yeah but my built 388 with a turbo will destroy the junkyard 350

[@claviaalfred8510]

Valentine Alfred

[@michaellecount8510]

I converted my proform 850 to a blow thru on my turbo Silverado and with a boost referenced regulator it’s pretty easy to tune. It’s a 6.0 with a pretty healthy cam and it cruises around better now than it did NA. Great video !

[@ctrain226]

I actually own an old cutlass jet fire carburated turbo charger amd its wild

[@nathan40307]

"Puts the turbo before the turbo". Yeah, that makes perfect sense.

[@TheRandynorris]

I built my own trap door system. It's base on the old accel turbo sonic draw through system using a q-jet carb and a turbo off a 6.7l cummings diesel. The only mod to the carb was to the idle circuit. It makes more noise than power and it set atop a 305 sbc in a craped out chevy luv built to look like a mini 40s truck. It does high 12s and everyone gets a good laugh out of it but it was super cheep to build and I don't take racing as serious as some guys. I do it for fun. Have a good day yall.

[@robertmoore4637]

I never researched this and glad I came across this vid bc otherwise I never would have known or cared to. Now that I know, I have more knowledge and understanding of other systems. Thanks for the info.👍

[@NightWrencher]

I appreciate it 👍 more tech videos coming soon

[@NMX777]

Read the 1968 Hot rod magazine article called "Turbo Tornado". It features an Olds with a 250 chevy straight 6. They put a draw through turbo setup on it and used a stock 2 barrel carburetor. The thing ran phenomenal with zero lag.

[@jamesshaw89]

Absolute fantastic straight forward explanation of how this all works, thanks for sharing this, subbed.

[@NightWrencher]

Thank you sir! I really appreciate it!

[@f-bodyjon2189]

TTA Performance has been making decent power on the 80-81 Trans Am turbo platform in recent years. Interesting draw through design. No reed valve like you mentioned though. That system feeds right into the turbo and the turbo is right on top of the factory single plane intake.

[@NightWrencher]

I should check that out and see how well it works!

[@denniswheeler7835]

I've ran a draw through setup on my old drag bike and it ran great. To the guys that are talking about their intakes getting super cold on a draw through setup that's correct they do, but that is before the air and fuel gets compressed in the turbo and as we all know when air is compressed the temperature goes up significantly but the fuel does help cool it some.

[@GlennLittleford]

Blow through is better from personal experience, once you sort out the fuel pressure modulation and air leaks. Blow through starts easier, idles better, and uses less fuel.

[@morganfreeman5171]

Renault used draw through setups in the 70's on their turbo F1 engines to reduce turbo lag. Also later produced a road car "renault 5 alpine turbo" with this principle !

[@TPVPRO]

Another problem with a draw through on a snail setup is the fuel has to go a long way like you said. No matter what the accelerator pump shot is not going to work right. It's probably going to have a stubble like a mofo off the hit.

[@NightWrencher]

It does depend on how you load it up. If you can get it spooling and run it a little fat on the hit, it should be ok but still not ideal compared to a blow through 😂 love your videos btw man 👍

[@TPVPRO]

@@NightWrencher We got to keep the carb game rolling. You're videos are awesome too bad you're not on the east coast.

[@NightWrencher]

I'll make it out there again soon 😂 furthest I've gone has been Missouri for the No Name Nationals. Gonna have to make the trip out there for LS fest or Moparty soon!

[@robertclymer6948]

Good to see you again Nightwrencher!! This video is absolute Gold IMO. I never really knew much about the draw through turbocharger. It just doesn't make good sense to me after hearing your explaination on it. I would opt for the blow thru turbo. I am not a big fan of turbos because of the plumbing and header changes etc. I personally would just get a roots or centrifical blower from Procharger or others. Thanks for sharing Brother. Cheers and blessings from Motown, home of the Detroit Muscle.

[@NightWrencher]

If I was gonna come back, I was gonna come back guns blazing 😂 Also: I agree all the plumbing is really annoying but its a small price to pay for reliable 200% horsepower on tap 😎

[@noboltsleftbehind]

Super helpful video, not a lot of information out there about turbocharging carburetors so having the two styles explained like this actually made a lot of sense.

[@NightWrencher]

You definately need to try it some day 👍

[@noboltsleftbehind]

@@NightWrencher let's first see the Charger or Frankenstein truck ripping it up!

[@NightWrencher]

If the charger finally gets a win, you gotta put a carb on one of your cars 😂

[@noboltsleftbehind]

@@NightWrencher whoa whoa whoa I’ll have to think about that. Haha

[@NightWrencher]

🤣

[@fookingsog]

As an additional extension topic, talk about single scroll vs dual scroll turbo!!!

[@NightWrencher]

Will do! Its on the list now!

[@thegobblerproject2363]

My VW is draw thru turbo and I really want a sniper kit blow thru

[@NightWrencher]

VW draw thrus work because the carb is up high so gravity helps things move along during low air speed situations. Having the carb before the turbo also allows you to run a bigger more common carburetor where before you had to stick with the tiny webbers to get things going on the street. Going to EFI would get you smoother, more consistant fuel curve so thats a huge plus. The drawback is the price and then the tuning if the self tuning doesnt work right

[@BigKandRtv]

Good lecture, and good dog.

[@manuqtix8874]

Pro and cons Draw through turbo pro -short boost pipe to intake -no intercooler or boost restrictions -easer to tune -fuel cools boosted air Draw through cons -oil can get sucked into the intake from turbo -fuel pooling in the intake manifold, boost pipes or turbo -poor fuel efficiency

[@ericsperformanceparts1647]

Direct Injection with Draw Through carb/efi for some added kick.

[@NightWrencher]

Thats what toyota did with the GR86 lol just without the boost

[@Zetor1234]

How do you prevent knock or detonation in a boosted carbureted engine?

[@NightWrencher]

You dial in your timing by locking out your distributor and switching to higher octane fuel like 91/93 or higher like e85. Boosted engines need a lot less total timing to make max power.

[@dipstiksubaru3246]

No different that you would on an efi engine

[@BADAZZ93STANG]

What about tuning??? Fuel and timing??? Any efi info???

[@NightWrencher]

Coming up in another video 👍

[@BADAZZ93STANG]

@@NightWrencher gotcha!!! Good info for the carb community...

[@matthewvarnam4302]

Billy's SRC channel had a Blow through 750cfm carburetor with twin turbos.....I think he was making around 1,600+hp.

[@NightWrencher]

I believe it!

[@Lazydomsgarage]

So my question is this what if you had a draw through but also had a blow through so it'd be a twin turbo but at the same time you have one pushing in the other one pulling through would you get have tunability issues let me know because I'm thinking of doing the 5-3 carburetor set up and now you have me wondering

[@NightWrencher]

The main drawback on a high performance draw through set up is that you run out of carburetor very fast and then the carb becomes the restriction unless you go way too big. In a blow through, you can push a simple 650 to over 1000hp and still have it drive fine on the street. Twin turbo into a single carb is that same as a single turbo. twin turbo into 2 carbs is a disaster waiting to happen because you would not be able to balance and match the flow of the 2 carbs. and 2 carbs on a single turbo like 1 blow through and 1 draw through at the same time would be redundant because a 650/750 blowthrough can supply more than enough air and fuel on its own and adding a second carb before the turbo just creates a restriction.

[@Lazydomsgarage]

@@NightWrencher so you wouldn't be able to have a blow through and a draw through with a carb between

[@NightWrencher]

@@Lazydomsgarage CAN you do it? Sure you can. Will it run better? No, it will probably run worse. Low horsepower you can run just a draw through but anything past 500whp, a blow through is the way to go.

[@Lazydomsgarage]

@@NightWrencher okay I thought it would be the best of both worlds with some Low end power and then get a top-end power out of it but thanks for the info appreciate it

[@NightWrencher]

@@Lazydomsgarage no worries, If you have any more questions, feel free to reach out 👍

[@kaylabentley-rd1qd]

I have a draw-through set up on a sbc. mostly just to be different. it runs just fine so far, but i am curious about mechanical vs vacuum carb? what would the advantages or disadvantages be?

[@NightWrencher]

Thats one thing I completely forgot to talk about. The fact that you can run a vacuum secondary carburetor in a draw through set up is pretty interesting. Since you cant run a vacuum secondary carb on a blow through, I'm not sure how one would react in a draw through set up. I like to think of a draw through turbo engine kind of acting like just a bigger motor so I assume that tuning the vacuum secondary for boost would be easier than a mechanical secondary

[@jamesstewart9307]

Must be dobble pumper blower carb boost ref to bottom manifold. 650or 750 holly

[@rockstareinstein9087]

Im not sure of you repliy to comments but i find your videos very useful. However i have used your videos to make a custom draw through set up for my 2376cc vw bug. I am using a 500 cfm 2bbl holley but i am not getting the correct response and or boost. The holley seems to be not tuned properly but i am at a loss woth this whole thing costing obscene $$ with less than stock power. What am i missing here?

[@NightWrencher]

Hey man, most draw through set ups that I've seen use a small 4bbl carb instead of a big 2bbl. You can use something like a 600 4bbl which will have smaller venturies than the 500 2bbl so your carb response down low should be pretty good. Going into the secondaries, you'll be able to get enough fuel to flow to feed the turbo.

[@Hill_billy_fred]

Old Buick T type had Draw-through carbs .

[@NightWrencher]

You're right, and they were good for their time but today theres no single draw through carb that can support as much power as a single blow through carb.

[@TheProchargedmopar]

You went to 1000cfm, Let's just throw on dual 1250s and call it a day. Imagine seeing that intake pipe sticking out of the hood. You could make it at least 1/2 the length of what thunderhead289 barely fit out of his garage. 😂

[@TheProchargedmopar]

Maybe make a big Y pipe like they had on the old Chrysler 426 Cross rams but instead feeding a draw-through Turbski. hahaha. My dad said those things ran like crap in the winter until about 10 min after cranking when things started to warm up. Doh!!!

[@NightWrencher]

Thats the trick 😂 once you get heat in it, the fuel will atomize easier so that helps a bunch. Blow through is the way to go 👌

[@ArmandoGuirola-mt8mz]

I have a 350 engine with a Roto-Master turbo, it has headers and high performance ignition. I’m trying to find out what kind of Holly I should use? It has a 4 barrel Rochester on a draw thru turbo intake I believe so. I’m trying to get more horsepower out of this engine. Without changing much.

[@dipstiksubaru3246]

Use the stock carb.

[@BomarBuilds]

Great video!

[@NightWrencher]

Thanks man! I appreciate it!

[@coolestguyontheplanet723]

Thank you, great video 😊

[@NightWrencher]

You're welcome! I've got more videos coming up soon!

[@dreadsndrags8603]

i dunno where u live but my draw through setup freezes the dam carb i had to install a carb heater and it still has condensation all over it occasionally steaming out the valve cover vent lol

[@Hircine101]

I'm kinda late to the party but i have a question for you. Do you have any advice about building a turbo 350 SBC with fuel economy in mind? I love making power as much as the next guy. But shouldn't a turbocharger help with the efficiency of the engine?

[@NightWrencher]

Hey man, I started replying a while back but it looks like the response was never uploaded. Basically, whatever MPG you get naturally aspirated, you'll get with a turbo. The only way a turbo helps with efficiency is when you install a SMALLER engine and then boost it. That's why the OEMs turbo 4cyl and 6cyl engines but not V8s. What I did was installed a 4.8(293ci) and then turbo it but then my truck didn't have enough torque down low for the tire size and gear ratio. You cant just put a tiny turbo and have it build boost all the time, it would just choke the motor. Hope this helps.

[@Thumper68]

When you’re adding air you have to add more fuel. I well running 350 can get like 20 mpg

[@MatthewTanti-p1u]

What about the the cycles in the trubo

[@NightWrencher]

What about them?

[@rayjguerrero]

What would you recommend for a 1999 Chevy metro 1.0L. Not trying to get crazy power, just a few extra ponies to keep my mph around 75 on hills lol. Most the time I got to down shift to 3rd gear and hold 55 to 60 mph. It’s just my little work car. Thank you for the video and any help or input will greatly be appreciated.

[@NightWrencher]

That's hard to say. On one hand your engine probably makes 100hp or less. on 15lbs of boost you're lucky to make 200 so a 200hp turbo would probably work. The issue will be the tuning. You will need an aftermarket PCM to control the timing under boost and then you'll need bigger fuel injectors to get more fuel to the engine under boost as well. Can it be done? Yes. How much will it cost? Probably close to 2-3,000 if you do the work yourself. Not worth it for me, but maybe for you it is!

[@dipstiksubaru3246]

A 50shot of nitrous. Or find the turbo version of that car

[@dipstiksubaru3246]

​@@NightWrencherhis engine makes 55hp lol

[@infamousnova]

Very informative

[@NightWrencher]

I hope you learned something 👍

[@geneendicott9228]

Great video.

[@NightWrencher]

Thanks man! I appreciate it!

[@stephenhotzjustdriveit]

thanks for the explanation

[@jakobkits-goldstein5878]

Draw through propane is the way.

[@NightWrencher]

Oh man, I havn't seen that personally but I know forklift carbureted propane work really well

[@chrisrobertson1929]

I own so many turbos they became ash trays ..my blowers are holding together

[@throttleblip1]

I thought all cars required starter fluid :-)... Mine must have an issue

[@NightWrencher]

You know, growing up I thought the same thing because none of our cars would start without it 🤣

[@throttleblip1]

@@NightWrencher learning lessons last A lifetime, always have a can of starter fluid with you at all times maybe emergency size mini

[@robertmoore4637]

And I subbed

[@elfmagejr82]

I think fiscally draw thru is better I'm trying to make it work on a big block so I'm trying to keep costs low for the first turbo build 😂

[@NightWrencher]

I don't think the price for either set up vary all that much

[@jamesstewart9307]

There trick for setting up a drowthrow carb you need idle bleed a faster idle to

[@dipstiksubaru3246]

If you're trying to do a turbo setup with low bucks, you're gonna have a bad time.

[@elfmagejr82]

@@dipstiksubaru3246 coming from the Subaru guy 😂 how's your head gaskets

[@dipstiksubaru3246]

​@elfmagejr82 perfect actually. Stock head bolts and gaskets on 26psi 0 issues.

[@chrisrobertson1929]

Funny 55 ..57. Ford fairlanes had. Huffers. ..lost tech

[@Trucking-q4j]

Your wrong about the air temperature a draw through setup the fuel cools the air also with a draw through setup the air and fuel are compressed and shoved into the engine. The only true difference is one needs a intercooler and one doesn't lol

[@NightWrencher]

I can see where you're going with this but youre missing details. A draw through set up cools the ambient air coming into the turbo but blow through set up will cool the charger AFTER the turbo. The difference is that some of the charge cooling effects are negated when the air is pressurized and tempreatures start increasing. On a blow through, the air that hits the turbo is already at its hotest point so once it mixes with fuel, it can only go down. Any turbo system can benefit from an intercooler but in both situations, it isnt nessesary if you have a safe tune.

[@larryfeasel2403]

eehhhhhh, wrong answer! The carb size is a restriction in BOTH ! Been there done that. Same power can be made with either

[@NightWrencher]

Wrong. Same engine, same turbo, same carb, the blow through will make more power. The draw through bottle necks much earlier than a blow through set up.

[@hermannortlepp5899]

You clearly have never used a draw through turbo system. If you are not using intercooling, your charge temperature is way lower in a draw through system, compared to a blow through system. For drag racing a draw through turbo system works very well. I produce 440 hp from a 2 liter draw through turbo engine. Sure blow through is great, but it is also way more expensive.

[@jamesstewart9307]

I disagree I'll ran blowthrow carbs sit 1985 on sbc and bbf. Thay work if you can tune carb it has to be a blower carb. You don't need a cooler air temp is lower it cold with fuel running throw fuel cooler by 30 degrees if you let fuel puttlup and I drive my car no problem. Put what you know

[@NightWrencher]

I read this 3 times and I still don't understand what you dissagree with 😂

[@jamesstewart9307]

My sbc with Garret t6 8893 works fine drowthrow I just run 950cfm holly blower carb

[@jamesstewart9307]

Run around 11,9 all day long grate air temps

[@project4bangers]

Bro what

[@DustySteel]

Puttlup 🤣🤣

[@travisblack417]

You ain’t slick with what upload day and time

[@NightWrencher]

Buddy, I don't even know what day it is today 😂 I just published it after it was done processing. Havnt even slept 😴

[@vintagespeedshop]

No Body remembers??? Its still common place in air cooled VW tuning and sandrails .

[@adamwebster9784]

What about making a blowthrough into a drawthrough? Hahaha

[@pnp8849]

I could swear you're a welder.

[@NightWrencher]

I don't know whatever gave you that idea 😂 but seriously. Theres a lot of welding when building a car so you're technically not wrong.

[@dutchylt]

Bs. The pontiac turbo 301 has never been so popular.

[@ArmandoGuirola-mt8mz]

I have a 350 engine with a Roto-Master turbo, it has headers and high performance ignition. I’m trying to find out what kind of Holly I should use? It has a 4 barrel Rochester on a draw thru turbo intake I believe so. I’m trying to get more horsepower out of this engine. Without changing much.

[@NightWrencher]

You have to imagine that your 350 now pumps twice as much air at 15lbs of boost so you're going to need something like an 850