Carb upgrade turbo engine ?

[Alexrobic604]

What's a good carb upgrade for a turbo engine, I heard the carter carb has all sorts of problems and isn't very reliable. Any suggestions?

[thewolfe]

The weber dcoe40 or dcoe45 is a very nice upgrade, especially with the progressive secondary mod. If you decide to upgrade to a larger carb then you also need to be prepared to add other things to keep your engine from over boosting.

[Scott V]

when properly rebuilt the yh is a reliable carb with no problems - or you can say no more problems than any other carb youd put on it.

the dcoe is a upgrade. figure like $400 *used parts* to $1000 *new parts* to put it on. the su type is another....figure $200 to $400 to put that on your turbo. q-jet $200 to $700. theres others you could use & youd have to make the adaptor to the turbo & the /throttle link stuff & fuel lines & get a air cleaner/etc.

-Scott V.

[notched]

The Quadrajet flows more CFM than any of the Webers do and they are a lot less money, but do require patience (as does the Weber) to get them set up. Most guys go for the Weber because of how it looks. Before you even consider a larger carburetor you should also consider how you will control the additional boost as it WILL require a waste gate and you will also need some kind of accurate timing/boost retard. The other thing is the stock case pistons are fragile and not forgiving to detonation.

[Alexrobic604]

Do you have any pictures of the Quadrajet carb? Or more information.

[Alexrobic604]

Ok are talking about a 4 barrel carb?

[thewolfe]

http://www.american-pi.com/corvair/corvhome.html" onclick="window.open(this.href);return false;" onclick="window.open(this.href);return false;

Go to turbo performance and you will see the adapter Ray sells and a few pictures. Yes the quadrajet is a 4 barrel. I'm thinking about trying a holley progressive 4 barrel that is "turbo prepped" from this VW site. I still need to call and talk to the guys there since they don't seem to answer emails but from the description it looks to be much easier to tune than a weber or quadrajet. This is the same place I got my dcoe adapter which mates right up to the 3" inlet on a rajay e flow compressor housing.

http://www.lowbugget.com/2_barrel_and_4 ... carbs.html" onclick="window.open(this.href);return false;" onclick="window.open(this.href);return false;

[Nickshu]

The best thing you could do for a turbo engine is install a Safeguard ignition system.

-Sent from my Galaxy s5 using Tapatalk

[flat6_musik]

I like the old 2GC and Holley 500! Don't know how easy it would be to find an adapter for them, but.......where there's a will, there's a way. Boy, those are simple, cheap and reliable carbs.

[miniman82]

As stated, 40 or 45DCOE is the primary choice. But you have to install a wastegate to control boost pressure, or it will run away and explode on you. Better timing control is a bonus for enjoying the added boost, but not required. If you have a 150 HP turbocharger, you won't be able to get vairy far without running into detonation problems because the compressor is so small. The B and F flow compressors are really bad past 11 psi, so if you want more than that an E flow starts to look like a good idea or water injection to cool things off.

[72BBNova]

As stated, 40 or 45DCOE is the primary choice. But you have to install a wastegate to control boost pressure, or it will run away and explode on you. Better timing control is a bonus for enjoying the added boost, but not required. If you have a 150 HP turbocharger, you won't be able to get vairy far without running into detonation problems because the compressor is so small. The B and F flow compressors are really bad past 11 psi, so if you want more than that an E flow starts to look like a good idea or water injection to cool things off.

I'm a little confused on part of your statement. Are you saying that when you go to a 40DCOE that you still need to run a wastegate? I had Warren Leveque modify me a new 40DCOE that I'm getting ready put on. We discussed the two, 40 & 45 and he told me for my car that I did not want the 45 because I would have to put a wastegate on it and it started to get into a lot more money, said I should see between 10 & 12psi boost with the 40, and with the 45 15psi or more. The combo I have is an EM exhaust housing with a LM compressor and carb, 304 cam, and an HEI ignition. I'm having a tank made now for a water/meth injection system, and I'm going to looking into the MSD digital programmable 6AL-2 with there HVC-2 coil for 6 Series Ignitions. Your thoughts on a wastegate with a 40 DCOE. My apologies to the OP for high jacking your thread. Jeff

[notched]

Jeff,
I would still consider adding a waste gate just as a safety measure in the case you do produce more boost. It definitely does not hurt having one.

[thewolfe]

I have a 40dcoe and before I put a waste gate in the car was hard to drive. If I got on it the boost would shoot past 15 psi and engine start knocking. This is with a safeguard and water injection. I was running an f compressor, b turbine at the time. It's hard to control the boost with your right foot! You can use smaller chokes that will limit things but isn't that why we use a bigger carb? Mine is set up with a 34mm primary, 32mm secondary. Now with a waste gate and electronic boost control set to 15 psi it's much more fun to drive.

[flat6_musik]

Hmmmm......it seems that adding a wastegate would be "the right thing to do" when going bigger on the carb, although......I can see how having the methanol injection will really help out here. But if me, I WOULD go with the wastegate. We're talking about the boost possibly being "all over the place" under varying conditions, loads and RPM. And on an air-cooled motor to boot?......naw.....I'd hafta have one.

[miniman82]

I'm a little confused on part of your statement. Are you saying that when you go to a 40DCOE that you still need to run a wastegate? I had Warren Leveque modify me a new 40DCOE that I'm getting ready put on. We discussed the two, 40 & 45 and he told me for my car that I did not want the 45 because I would have to put a wastegate on it and it started to get into a lot more money, said I should see between 10 & 12psi boost with the 40, and with the 45 15psi or more. The combo I have is an EM exhaust housing with a LM compressor and carb, 304 cam, and an HEI ignition. I'm having a tank made now for a water/meth injection system, and I'm going to looking into the MSD digital programmable 6AL-2 with there HVC-2 coil for 6 Series Ignitions. Your thoughts on a wastegate with a 40 DCOE. My apologies to the OP for high jacking your thread. Jeff

I wasn't there to hear his rationale, but my guess would be the 40 has venturi so small it's still limiting boost to some degree. Please understand how the Corvair's draw through system works: the YH was chosen carefully, because of the design of it's venturi it will limit boost to around 8-12lbs. Once the air going through it reaches a certain speed, no more air can flow. Since it's ahead of the compressor, this has the effect of limiting the amount of air the compressor can ingest, hence the amount of boost pressure it can create.

Once you remove this restriction, you open the door for more airflow and more boost. So if you don't take steps to control that airflow with a wastegate, the potential exists for runaway boost and engine destruction. I personally wouldn't feel comfortable running without one, since even a stock Corvair has boost all over the place depending on how it feels any given day of the week. One day you can't get more than 8, next day it's cold out and you get 12+psi. Besides, getting more boost is one of the main reasons to swap out the carb. Why shoot yourself in the foot by still having venturi that are too small?

Wastegates are not difficult to install, you just weld in a flange on the turbo 'up' pipe and dump it to atmosphere. You can also plumb it back into the exhaust before the muffler, if you need a quiet ride.

[72BBNova]

Thanks for the reply Nick. I've started a new thread for myself.

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