rear mounted turbocharger?

[smokin2001Formula]

I was wondering if anybody knew anything about these rear mounted turbocharger units from Squires Turbo Systems. They were made visible to me by GM Performance High-Tech magazine. Are they any good? The magazine did an article on the units with LS1 engines in GTO's and Trans Ams. Any help will be appreciated.

[Performin Norman]

My friend has one on her T/A. With no other mods and a bad tune, she put down 465/508. Whether it is a good unit, that is up to you to decide.

[94 formula]

If you try searching here and some other forums you will hear a lot of debate on them. Some say that their a great idea and a great way to keep the underhood temps down while others say that the tubro is too far away and that there will be a lot of lag. I'd try talk to some people who actually have them and see what they think about them before trusting any magazines or the reviews posted by the turbo manufactuers.

[fastTa]

The STS systems are very good. Mounting the turbo further from the hotside does create a bit more lag, BUT it is barely noticeable. Their "off-the-shelf" kits put down some very impressive numbers on internally stock cars.

How about an STS setup on a built motor. Check out this C5 going 9.33 on only 13 lbs! :

Video http://www.learntodragrace.com/mike933.wmv

99 C5 Vette FRC
Cartek built 388-cid LS1 , Cartek prepped AFR 225 heads , Cartek turbo grind cam , LS-6 intake , stock PCM , Cartek LS-1 Edit tuning , stock mass-air , stock exhaust manifolds.

Cartek/STS custom rear mount turbo kit with Precision GTS-76 turbo
4L60E Transmission built by Rodney(RPM Transmissions) 3.42 gears

Best ET 9.331 at 149.18 , 13lbs of boost on a 16-inch MT Drag radial.

[94 formula]

The STS systems are very good. Mounting the turbo further from the hotside does create a bit more lag, BUT it is barely noticeable. Their "off-the-shelf" kits put down some very impressive numbers on internally stock cars.

How about an STS setup on a built motor. Check out this C5 going 9.33 on only 13 lbs! :

Video http://www.learntodragrace.com/mike933.wmv

99 C5 Vette FRC
Cartek built 388-cid LS1 , Cartek prepped AFR 225 heads , Cartek turbo grind cam , LS-6 intake , stock PCM , Cartek LS-1 Edit tuning , stock mass-air , stock exhaust manifolds.

Cartek/STS custom rear mount turbo kit with Precision GTS-76 turbo
4L60E Transmission built by Rodney(RPM Transmissions) 3.42 gears

Best ET 9.331 at 149.18 , 13lbs of boost on a 16-inch MT Drag radial.

That is very impressive. One thing I always liked about turbos is that with a V8 you can drive it on the highway at 1500 rpms and not have the turbo kicking in but when you want to get on it its there.

[LORDVADER]

Friends:

Here I have a friend with one of the early systems under his ´98 Camaro and he is a real believer. The car goes fast enough but I think that it is not cheap when you consider an intercooler and related fuel system as for a medium boost system or beyond.

He grants in a private way he spent about 10,000 USD including the installation trip and custom tuning. He is obtaining about 9 psi gauge reading at 7350 ft altitude. He had some drivability issues, apparently because his system has de MAF sensor on the throttle body entrance. It seems locating this before the compressor inlet avoids this problem.

Report is that this car is doing 12.55 seconds here (altitude) and about 450 corrected HP. I can testify 13.8 seconds videorecorded.

My personal opinion is that it can constitute an advantage for the installation design and operation characteristics like turbo lag which it seems to be very moderate or normal, at least on boost levels from 5 to 9 psi, maybe 11. Above this it is very likely you require an intercooler and fuel system improvements. End of investment value.

STS says they have exclusive turbine scroll designs to eliminate boost lag.

About the alleged intercooling effect of the long pressure intake pipe; a friend of mine who is an engineer related to heat exchangers for seashore oil drilling plataforms, explains this is maybe possible to some degree during the short time of a 1/4 mile burst with a cool start up, but not possible on a high speed constant operation condition once the pipe is saturated with the heat of continuous pressurization, because the cooling surface area is very small compared to the area exposed in an air-to-air heat exchanger, at least not for the alleged 100F intake charge temperature decrease.

I know the system was conceived for trucks, suppose it should be very good on low boost mountain climbing or towing for example.

My conclusion: It depends on boost level and driving requirement.

And you can have more conventional systems for about the same money on the basic kit. Try this:

http://www.proturbokits.com

Regards and good luck.

Lordvader.