Single turbo over a supercharger for LT1?

Last Ride · 10-21-2002, 04:16 PM

Hey gang,
With all of this talk of twin turbo setups, I have wondered what would be involved for a single turbo setup. What kind of lag problems would this present? There has to be a reason people are going with the twin over the single. I was just wondering as I am still reasearching options for a hi-po motor for my '78 (or whatever comes next). It just seems at first glance that a single turbo would be easier (and thus cheaper) than a twin setup. Would this be a viable option over a supercharger? Any insight would be greatly appreciated. :cheers:

bill mcdonald · 10-21-2002, 07:34 PM

I think people go twin due to plumming issues.

With a single you have to connect the other banks exhuast to the turbo. In a C4 and I am sure a C3, you will have the turbo on one or the other side of the motor. This is a problem getting the exhuast to the other side of the engine. if you go under the engine you might have issues with ground clearence.

This also needs a pretty large down pipe maybe 3-4 inch diameter on a single which might be hard to get out of the engine compartment.

This is why I mainly think people go twin. A turbo on each bank, and a smaller down pipe can be used to exit the engine per side. PLus it just sounds cool. but the same can be had with a larger single, but you get the lag from larger rotating mass.

I think a single work just fine. I think Lag would be to a minumum with a proper sized turbo. if you makes tons of power you might want to go with a bigger turbo to put some lag in there. V8's make some good power without a turbo anyhow, so the lag could become your friend. Depends on how you set it up.

[Modified by bill mcdonald, 2:35 PM 10/21/2002]

Last Ride · 10-22-2002, 10:30 PM

I had a single turbo on the old L48, and it ended up toasting the eninge (the install was not that great, and it was over 20 years old!) What about building a stroker with good low-end torque to help compensate for the lag, then a large turbo to really scream when you romp on it!?! Could such a balance be reached? I am not looking for an all out drag car, but the car is a weekend warrior with occasional runs down the strip. Am I dreaming here or what? :cheers:

bill mcdonald · 10-22-2002, 10:46 PM

I am sure it could work.

HAve you checked out montys car?

He has a 427 SBC with twin turbos. When he lasted played with it he posted something to the effect that thr turbo may be too small. I think he was spinning the tires at 1/2 throttle or something a like.
He mentioned that he might move to larger turbos to put some lag in there.

Rkreigh · 10-23-2002, 08:19 AM

with a nice turbo, lag isn't bad and actually needed to keep the torque from coming on too suddenly and roasting the tires.

something like a T72 with 65 lb injectors would work really well. problem is getting the plumbing (manifolds, intercooler, downpipe) pipes done for a reasonable price. the exh manifolds need to be high quality SS.

on my buick turbo, it has a TE45 and lag IS NOT a problem, traction is and it's only a 3.8 v6.

turbo cars make a ton of power, but you need to lower the compression ratio to around 8 or 9 to 1 (depending on boost) and get the fuel/spark curve programmed just right for the boost.

anyone building an LT1 "kit". I just purchased a nice LT1 94 Auto (turbos work really well with slushboxes) that is a GREAT candidate for a turbo.

please let me know if anyone wants to pursue doing this. I have some turbo experience and would love to get this kind of a project going. I have been researching doing a twin turbo ZR1 but the high cost of the engine mods hold me back a bit.

the LT1 396 stroker kits are economical and VERY strong. good foundation for the turbo project.

FYI, my turbo buick runs 26 psi, and is making close to 700 HP from a little 3.8 v6, FAST but not too durable). I've blown HG and broken cranks, main caps, it's a grenade!!! ;>)

you need a strong foundation and plenty of fuel flow for a well executed turbo. it won't be cheap or ez, but well worth it. :D :eek: :cool:

Last Ride · 10-24-2002, 07:46 AM

Quote:

anyone building an LT1 "kit". I just purchased a nice LT1 94 Auto (turbos work really well with slushboxes) that is a GREAT candidate for a turbo.

I have found one place making a single turbo LT1 "kit", but it is only for the F-body :cry I am sure a single turbo can be done at least in a C3, because my old L48 had one. The kit adds over 100 horsepower, supposedly, at a cost of under $5000!

Quote:

please let me know if anyone wants to pursue doing this. I have some turbo experience and would love to get this kind of a project going. I have been researching doing a twin turbo ZR1 but the high cost of the engine mods hold me back a bit.

the LT1 396 stroker kits are economical and VERY strong. good foundation for the turbo project.

FYI, my turbo buick runs 26 psi, and is making close to 700 HP from a little 3.8 v6, FAST but not too durable). I've blown HG and broken cranks, main caps, it's a grenade!!! ;>)

you need a strong foundation and plenty of fuel flow for a well executed turbo. it won't be cheap or ez, but well worth it. :D :eek: :cool:

I was thinking about doing mine in stages. I wanted to put the turbo on now at pretty low boost levels (comparable to a supercharger), then rebuild the engine and add boost. 396 sounds about right! Wouldn't a single turbo be more cost effective than a twin? Anyway, will keep this all in mind. I have more time than money!

mn_vette · 10-24-2002, 05:26 PM

Quote:

I was thinking about doing mine in stages. I wanted to put the turbo on now at pretty low boost levels (comparable to a supercharger), then rebuild the engine and add boost. 396 sounds about right! Wouldn't a single turbo be more cost effective than a twin? Anyway, will keep this all in mind. I have more time than money!

Stages are definately the way to go. If something doesn't work you can still back out with minimal losses. Cost savings for a single vs. twin isn't as easy as saying I only have to buy one turbo instead of two. You can get a brand new T4 turbo for $425 so $850 for the pair, a T72 turbo will run you somewhere in the same ballpark maybe a little more. The intercooler is another big hit on the pocket book, 500-1000+, but you don't need it right away. The headers are the next big item. Having those custom made are a little pricey, especially out of Stainless steel. Im having one made out of mild steel to get the design down and to test my system after that I'll be getting it remade into stainless. But single or twin way it's going to be alot of custom work. But lets not forget the downpipe, airfilters, and piping to the intercooler then to the throttle body. With a single these are larger pipes instead of twice as many smaller ones.

Overall I think the costs are comparable, the question is which one is easier to engineer. Take a good look at your engine compartment and see if you can borrow a turbo and some piping from somewhere and see if it will actually fit where you think it will.

Be prepared to drop about $5000 into it after all the little things for the whole system when its done. And be prepared to spend lots of time!

Last Ride · 10-27-2002, 08:17 AM

Quote:

Be prepared to drop about $5000 into it after all the little things for the whole system when its done. And be prepared to spend lots of time!

At $5000, it almost seems like a deal! Depending on the type of power you can pull from it, comparable supercharging kits cost upwards of $4500. I will keep researching this as I am debating on what to do for power for my car.