Turbo with a carb???????

[IXLR8]

I was wondering if i could turbo my carbed 3.4 ??? Its got a edelbrock torker II intake with a holley 390cfm carb is there (bigger Carb isnt a problem). I would like to Fabricate a mount to make it adapt to the carbuerator so i could force induct with a carb. Could i make the turbo's off a dodge stealth VR4 work???? I have an idea for the mounts on the carb. And does anyone know if the turbo's on those have a wastegate?? Here is kinda what i was thinking about doing in this picture below if it works

[bszopi]

RE: Turbo with a carb???????

Look at the Vortech SC for the 4.3L carb'd engines and design something similar. Should work just as well...

[madness_spirit]

past experience has shown me that any turbocharger off any car will work in any car, you just need to get exhaust fabbed up that will mate to it, intake plumbing that will fit, and figure out the best way to deliver oil to your turbo. as far as the techical aspects of boosting a carb, you are on your own, but it should work, you may have to figure out some tweaks to deliver more fuel at higher boost pressure, you cant simply deliver more fuel all the time because turbos dont create as constant boost as a supercharger does

[Froggx]

Turbo's from stealth vr-4 should be decent. They are internally wastegated, all mitsu turbos of that size are. Don't forget, often a turbo system will respond better to a carb that is actually smaller than the NA counterpart. Also, I'm sure if you're working up mounting stuff, you probably know all about the things you need to do to your carb to make it work: fuel pressure adjustments, sealing throttle shafts, making sure everything runs right (using the secondaries as fuel enrichment only under boost is an awesome idea), maybe building a boost box (could be easier than sealing everything), finding boost safe floats (can't having them collapse after all), etc. Do you know if there are any sidedraft carbs that would fit on your manifold? Those would be more graceful and better for hood clearance than making an adapter. Also, what is this going into, some vehicles have space limitations and such that aren't really obvious at first. Also, good choice going with a blow-through setup, draw-throughs suck.

[IXLR8]

Its a 85blazer. I want to do a turbo but im gonna need alot of help and ive been reading around alot on turbo charging carb engines.I found that ppl are saying that Demon carbs are best for this but im not sure i was goin read some more and look around no i didnt know that i needed to do all that froggx. And does anyone know where a good set of low compression pistons are??? I dont know if this would be the forum to ask but what is boost pressure on those stealth vr4s??? thanks

[Froggx]

Regarding the boost pressure on the vr4's, it probably isn't relevant for your install, but I think it's around 8 psi. I say it's probably not relevant for you though because if it's like every other internally wastegated mitsubishi turbo I've worked with, there is an adjustable shaft that let's you set it to nearly whatever you want. Also, it's likely an electric solenoid works as a boost controller in the car which would modify how the turbo reacts. You can spend less than $50 on a manual boost controller and set it wherever you want for sure.

Also, I know some manufacturers, but can't remember which off the top of my head, make carbs that are "turbo ready" which is what I would go with personally as it would save a ton of effort in preparation.

[Jack_96Lumina]

The VR4s have 9Bs... very small turbos. It is hard to find a used one in good shape because a lot of us like to put larger wheels in the stock housings... to save $$$ cause everything else is crazy expensive.

The 1st gen VR4/TTs ran 8psi stock, the 2nd gens removed a boost restrictor from a box on the firewall to get 12psi. I currently have my 9Bs making 14.5-15 psi. After that they work more like a hair dryer... so if you don't plan on making more than 15psi you should be fine. They are very efficient @ 5-8 psi and you could possibly run no IC, or atleast a small IC off of a 1G DSM or a VR4.

Lag for me is not an issue. I have a 3.0L DOHC V6... the boost is instant on a turbo this small.

I will be upgrading to the 1st gen DSM turbo, the 14B, as an easy way to make 450+ AWHP. I will also be upgrading to 1st gen SMIC, two of them, and that will keep my intake temps nice and low. The SMICs on the VR4 are small but work fine for the stock 9Bs at stock boost levels. They get kinda hot after a few runs at the track @ 15 psi though.

Good Luck, let me know if you need anything

[IXLR8]

Well i called and asked and there is a guy down here that will sell them for $275 a peice(there brand new) is that a good price? I found this place here that makes blowthrough carb's if anyone needed this http://www.tpcracing.com/ .

[Doubt_Incarnate]

i think your 85 blazer already has and 8.5:1cr, even if you swapped in the 3.4 crate motor, but dont quote me on that.

[IXLR8]

Ive got the engine out of a 95 camaro so im not sure what the compression is for sure i need to fine out

[Doubt_Incarnate]

oh, i think thats arouns 9.5 or so. maybe you can check into the fwd pistons, from a Grand am. they have a deeper dish and will drop the cr, but i dont know if it will drop too far. Stock fwd pistons, if they would work, are a budget alternative to forged ones from ross.

[Froggx]

according to the site the 3.4L iron head has a 9:1 cr, this is fine for running 10 psi

[Wolf]

here is a pic of my carb'd turbo buick 3.8

thats a draw thru setup(the carb comes before the turbo, like a roots blower)
if you can fine one of these turbo & carb setups(78-83 3.8in buicks, 80 &81 in monte carlos,and 79-81 301 turbo trans ams) you can make a adaptor plate and mount it on your edelbrocks lower intake

[Guest]

Ive got the engine out of a 95 camaro so im not sure what the compression is for sure i need to fine out

Bad idea, do not attempt to use Aluminium head pistons in an iron head engine, the SCR will drop to around 7:1, way too low to be effective. Off boost power will be horible, off boost throttle responce will be well not even thought of as being there.

9:1 is a good SCR for these engines when force fed it seems. I am running 8.9:1 currently with an an aluminium head hybrid, running 9 PSI (Boost cut ), which would be equvilant to around 12 or 13 PSI on a stock iron head engine (PSIG is a measurment of restriction).

Carb presents some other tuning issues that I don't have....
Usually when force feeding a carburator equipped engine, the SCR will be kept on the low side, most commonly between 8 and 9:1, due to spark knock, and having very little control of this on the fly, like a KS based EFI system has.
Added fuel is generally a little difficult to add with a carb, but with proper modifications to the carb and fuel pump, it can be made to work very effectivley.
I'm not going to get into effective SCR changes where Iron VS Aluminium are concerns, since aluminium head is really not an option for you.

[Doubt_Incarnate]

i thought that in maximum boost they stated that since carbs work on the pricipal of a pressure change, the necessary fuel was already there, you just need to up the fuel pressure to counter the boost pressure. but its been a while since i cracked that book, since boost for me is far away $$$ wise.