Bling

After hearing about the long wait at SRT to get twin's installed, I started looking around locally to see what could be done. I have one pretty experienced guy that wants to go with a single garret t-78.

What do you guys think I need to make sure the local guy does to meet or beat the SRT specs. I want to run 11's on street tires, but would settle for low 12's.

Richard

By the way, it's a 98 GS400. The 6 point roll cage is getting installed may 27th.

TTurboPimp

iTrader: (12)

Im not sure about the #'s for the GS, but when I had my TT SUpra I changed it out to a Greddy T78, then Greddy T88. I put down 796 rwhp with the T88, and with the T78 numbers were in the real high 600's, almost 700 rwhp. I preffered the T78 over the T88, it spooled up alot quicker, and the bottom line is you cant hit those numbers without running race gas anyhow. How often will you run race gas? Probably not very often. The T78 should be a beast on the car with the right supporting cast, feul system, management system, etc, etc, etc..

Bling

I go through gas waaaaaaaaaay too quick to have to find race gas everywhere I go. I've seen my avg mpg in the 9's.

TTurboPimp

iTrader: (12)

The Supra hit in the 500's on pump gas, imagine what the Lex would be like with those #'s!!

Mariusz

Gotta love the attitude. Low 12's is quite an accomplishment for any car on street tires, especially a ~4000lbs (with you in it and a set of aftermarket wheels.......not to mention the extra weight of the roll cage) GS4. I would honestly say that hitting 11's on street tires would require more than a good driver and a high HP GS4........it would require a prayer too. Unless you are referring to 11.9X as "11's" which might somehow be feasable. You will probably need more than 500RWHP and I can tell you from experience that anything even remotely resembling that power will get your street tires spinning as if you were on ice.

Another thing you should consider is the fitment of a T78. I can tell you that you are not going to fit it underneath or up front as SRT has done with the T3's. This leaves you very little or no room to play with near the sides of the engine bay. After you properly fabricate the custom manifolds, I believe this will only become a bigger obstacle. Unless of course you are willing to sacrifice the luxury aspect of the car or/and its amenities and rip apart the engine bay. Also, have you thought about the spool? T78 (although some may disagree here with me) starts life somewhere around 4300-4600RPM. What kind of a power band does that leave you with an auto? What about the lag? Are you ok with that? Will this be a drag car or a street car? Are you going to raise the rpm line to get a better curve from your turbo?

Fitting a big turbo or turboing a GS4 for that matter is not just a bolt on project. The GS4 was designed with "luxury" in mind and there are other important things to take into consideration as connecting rods, pistons, and the transmission....to mention a few. Anyone who claims he can do this type of a project for you needs to be asked several questions. Who is going to rebuild your tranny for you and how much HP will it hold? What kind of pistons and rods will he use? How long will you have to wait for the piston/rod manufacturer to fabricate this "one of a kind" set of pistons and connecting rods. What kind of a warranty/support will you have? Will your car be the R&D guinea pig? What is their experience with modding high HP cars, in particular the GS line? I know you mentioned that the wait for turboing a GS4 at SRT is very long, but I am just curious if you had a chance to speak with them personally about this?

Accomplishing what you want is definitely possible as in the end it always depends on how much money you want to spend. I would love to see a T78 GS4 with a 9K RPM redline and a 6-spd tranny putting down over 700RWHP, but I have yet to see one. My only concern is that you give some consideration to other issues in addition to the type of a turbo you will be using. I wish you lots of luck as well as success on your project and don't hesitate to ask questions.

TTurboPimp

iTrader: (12)

I have thought about selling the GS4 in the past, with intentions of getting a GS3 and using one of many bolt on kits that are available for that engine. If Im correct, the GS3 has the non turbo Supra engine in it, which gives you many single turbo KIT options. No R&D time , money, worries. you would still have the other obstacles, feul system, tranny, possibly drivetrain, management system, etc... But it would be bad *** wouldnt it!

Richie

Mariusz, what is the latest on your car?

Bling

I've not been able to verify it yet, but I hear the motor can take up to 8000 rpm stock. Even if its not true, since they have to sleeve the block, and install different pistons anyway, I wonder if anything more than valve springs is needed. Any ideas on this one?

Bling

By the way, the cageman says the cage will not way over 300 lbs. Its chrome molly.

TTurboPimp

iTrader: (12)

Just out of curiosity, why are you getting a cage? You shouldnt be anywhere close to getting kicked off any tracks for the lack of having it, are you? Is it jus the wow factor, or are you prepping for some 10 second passes?

Mariusz

Richie, it should be tuned and dynoed by this Friday, but I won't be able to pick it up untill I get back from Florida on the 22nd. All in all it should be "complete" and broken-in really soon.

You will also need titanium retainers to be able to rev that high. Keep in mind that you will also be decreasing the life expectancy of your motor. Having an 8-10K redline does not come without compromise. For example, raising the rev limiter on the Supra would probably cost a mere $400-$600. It seems that it is a "no-brainer" upgrade especially for those big singles, however, I assure you that a lot of single supra owners opt out on this mod.

Bling

Truthfully its a safety issue. If I ever in a collision, I want maximum safety. If the car dips into 10's, no brainer too.

JZS14SEVEN

willing to scrafice that much interiour space for safety???
cage plus padding... must take up some space..
wouldn't want to place any bare metal objects any closer in a collision than they have to be
"safety"

TTurboPimp

iTrader: (12)

If you dip into the 10's its more than a no brainer, its necessary if you want to take more than 1 pass down the track. Most tracks will boot you after 1 run in the 10's if you dont have it, but you got alot of work to get a GS into the 10's!

Bling

Well, I will keep you guys updated. We are definitely doing the big single. Fully done up tranny (although it would have been 2k cheaper to do a th400.) 1 off JE pistons (takes forever), drive shaft, built supra rearend, apexi this that and the other. The tein pillowtop setup, and ported and polished everything.

We will hit 750 to the rear wheels, and I am told that it will be very violent.

Will let you know as soon as I have the exact specs in hand, and will be getting him the money to order the pistons asap.