Saw a program on tv the other day where they mounted twin turbo's on a new style corvette at the back basically where the stock muffler would mount.

So they had to run quite a length of inlet pipe from behind the wheels/turbo's back up to the engine intake/intercooler. And also quite a length of oil cooling lines to the turbo's.

Seems like it might be a good idea, because you get the heat away from the engine compartment although it is close to the gas tank unless mounted in the trunk.

Has anyone tried this on a Chevelle?

Thats a recipe for turbo lag. However Porsche have run their intercoolers in the front, while the turbos of course are in the back, and that requires quite a bit of tubing, yet they have very very little turbo lag, but thats Porsche, they're pretty good at what they build.

Here is a link to a turbo site that specializes in the remote turbo mount setups. They maintain turbo lag is not an issue.

http://www.ststurbo.com/

I would like to pick up a second with minimal effort. Other than going with a small nitrous setup, the turbo setup seems like the ticket.

With the turbo's you don't need much cam or cylinder head cause you got forced induction. Having less cam is a big advantage in terms of valve train maintenance and breakage. And you don't need to spend a fortune on cylinder heads, you spend the fortune on the turbo kit instead.

It works fairly well, but has a few disadvantages. There is more lag. They also hang down under the car, real low in some cases. Also have to watch the air intake for water injestion in rain and puddles.

Some have complained of cheap parts on some things in the kits. And several GTO guys are selling there's for a regular up front twin turbo system, as they are not happy with the lag.

Jody

Thats a recipe for turbo lag. However Porsche have run their intercoolers in the front, while the turbos of course are in the back, and that requires quite a bit of tubing, yet they have very very little turbo lag, but thats Porsche, they're pretty good at what they build.

Are you sure? All 911/993/996 turbos I have seen typically have the intercooler mounted on top of the engine and ducted via the top of the whale-tail for the earlier models, or they are mounted sidesaddle and fed by the scoops on the side of the car just behind the doors for the later models.

STS has got the rear-mount turbo setup working well. It's not as efficient as mounting them close to the engine for many reasons, but they do still work when mounted further back. They won't spool as quickly, but they will still make boost.

Rear mount turbos is not in any way a new concept-- Republic Aircraft did this back in the 1940 on the P-47 Thunderbolt. The turbocharger was mounted aft of the cockpit and fed by 26 *feet* of ducting each way!

I have considered a "mid-mount" turbo setup on my car by getting rid of the back seat and hacking up the floorpan. Mount the turbos where the mufflers typically sit on these cars, then build airboxes up in the interior and feed them by NACA ducts blended into the side of the body. You wouldn't be able to roll down your rear windows anymore, but oh well. The turbos being low and in the center of the car would help the CG and polar moment of inertia too. It would help alleviate the cramping & heat under the hood of a standard turbo setup and the plumbing to and from the turbos wouldn't be too horrendously long. You still have to deal with oil scavenging though with the turbos mounted at oil pan level. I still kind of want to try the "mid mount" setup but I figured if I was going to all that effort why not mount them up front where they're the most efficient?

With the turbo's you don't need much cam or cylinder head cause you got forced induction. Having less cam is a big advantage in terms of valve train maintenance and breakage. And you don't need to spend a fortune on cylinder heads, you spend the fortune on the turbo kit instead.

Actually, good heads are very important with forced induction as you are now moving a greater quantity of air, especially on the exhaust side. Compressing the intake charge will make up for poor intake ports up to a point. However, a poor port will require more boost to make the same power as a good head can make with less boost, and the good head/less boost combo will have less charge air heating which also makes more power. What stands true for naturally aspirated engines is also true of boosted engines-- there is a LOT of gain to be had in the heads!

Are you sure? All 911/993/996 turbos I have seen typically have the intercooler mounted on top of the engine and ducted via the top of the whale-tail for the earlier models, or they are mounted sidesaddle and fed by the scoops on the side of the car just behind the doors for the later models.


And all said Porsche models have a rear-engine setup, so a rear-mounted turbo only makes sense.

-Dave

Gokou,

Some good info there.

I am only looking to get to the low ten's, definitely not under 9.99 because of all the extra safety requirements for car and driver below that.

So I would not need to push the turbo setup much to achieve the minimal boost required to pick up another second or so. Lag should not be a big issue because the normally aspirated motor is pretty healthy as is and just needs a bit of a "boost" to give it that bit of extra charge going down the track.

I am not sure how easy it is to get another second out of my 454 on pump gas with just a cylinder head change. I already have quite a bit of cam at 262/272 duration and 0.670 lift, but maybe stock oval iron heads are limiting the cam. Already have a high stall 8 inch converter.

Probably easiest is to go to a mild 500+ cuber, but kind of stretches the budget a bit.

The few turbo cars I have seen are very impressive.

A good single stage nitrous set-up would be a bunch cheaper and easier to package.

Are you sure? All 911/993/996 turbos I have seen typically have the intercooler mounted on top of the engine and ducted via the top of the whale-tail for the earlier models, or they are mounted sidesaddle and fed by the scoops on the side of the car just behind the doors for the later models.


It was a long time ago i saw a diagram that showed piping throughout the car... perhaps I mistook the radiators for the intercoolers.