Scottie-GNZ

I can give you my experience from a GN/TH200-4R perspective. The Buick Turbo version is controlled by the ECM and locks up in OD at about 45+mph. The ECM does not lock up the converter at WOT so you need a manual switch. I lock mine 2 secs after the 2-3 shift so I can get the maximum MPH in 3rd. Lots of Buicks hit the switch manually at the line and the converter locks up after the 1-2 (it does not lock in 1st). A strong running Buick will gain .2 and 2mph locking up at the line. The engine gets bogged down when it locks up in 2nd but the massive torque pulls it through. Its a catch-22. Locking up the converter does take its toll unless you have an expensive multi-disk converter. It helps that our cars are so light. If you do not lock up you are giving up a little ET/MPH. If you run out of RPMs in 3rd and do not lock up, shifting to OD is also hard on the tranny and results in a massive drop in RPMs. If you are not running out of RPMs in 3rd at the traps, try locking at the line a couple of times then try after 2-3. Evaluate the results and make a decision.

Maybe not MOF it might be damn "hard" shifting with the GF always wanting to "sit" so close all the time

It is a lot easier (but more expensive) to make more HP for a big MPH than it is to get the car to launch hard for a quicker ET. ET wins races, MPH is a HP indicator and bragging rights. I had no success with 17" Nittos (275s) and I doubt the 225s will do the job with 400rwhp. Try it and then decide. If you are going to get a 2nd pair of tires for the strip, then do what I did and get a pair of Hoosier QTPs. They are DOT-legal but you do not want to be driving on the street with them a lot. I live 9 miles from the track and they never see an inch of road beyond that. However, throwing those on will not guarantee you 1.45s like I am getting. Getting the suspension set up is also key. The average street shock is going to compress/rebound normally and that is not what you want for the strip when looking to break into the 10s. A street car will need adjustable shocks, like Illuminas, or sacrifice the launch with wheelspin or worse, wheelhop. You want the front to rebound quickly and compress slowly and the rear to compress quickly and rebound slowly. This will give instant weight transfer and not unload the rear too quickly. Ever see a turbo launch then start spinning the tires 20' out when the big boost comes on? The Illuminas allow you to make that suspension adjustment for the strip and back to carving canyons if you have to. Thats one of the main problems with your car James. Even spraying out of the hole, I doubt your setup has more low-end torque than mine, yet I was cutting low-1.60s on a t-brake with the same DRs you have with nary a trace of wheelspin. If you are serious about getting QUICK ETs, then think about this: for every .1 on the 60' you affect the ET by .15. The first 1/8-mile is spent building acceleration and the 2nd half is for top-end MPH. With your 11.2 you are going to spend ~7.15 to run the 1/8-mile and ~4.14 to run the 2nd half. How important is the launch in drag racing? BTW, lets not start the rear-end squatting debate again

No its not.

To predict the 1/4 time/speed, I have to make some assumptions: - the car weighs 2,700lbs w/driver - you can cut at leat a 1.80 60' - it really does have 400rwhp With that it should go 11.20s @ 123-ish

Mike, there are cars running in the 8s with the 345 BFG DRs but do not condier them for an everday tire. Closest you can come is the 275/60-15 Nittos. They certainly will not fill your fenderwell but they will HOOK!. Pete, DRs not needed on the fronts. Unfortunately, neither has a great selection of sizes. Unless you are hung up on having matching F & R, stick with what you have on the front and put the Nittos on the rear. I am running 275/40-17s on 17x8.5 on the rear.

http://zdriver.com/members/scottiegnz/ic.html

I have been preaching the wonders of using the Nitto DR as an everyday street tire for very high HP cars. The bad traits of DRs on the street (rain and tire wear) do not apply to the Nittos. Since putting mine on, I made several trips to the track and the 2 recent events I drove to totalled almost 2,000 miles themselves. It looks like I might have worn them down .1mm Unfortunately for me I could not get the 275/40-17s to hook on 10-sec passes but I would not leave home w/o them. I fear driving my Z in the rain, not because of the Nittos (no problem there) but because of the sh*tty wiper system. No need for a suspension change with that awesome R230 setup or massively wide tires, just focus on tire compound. Nitto DRs or Toyo Proxes RA-1.

To extend on Bob's response, I had no traction with 275/40-17s after consistent low-1.60s with 275/50-15 and 255/50-16. The sidewall is just too short and stiff, but since you already have them, give it a shot. As a comparison, RickB is spraying a SBC and ripping off the line with 235/60-15s. I ended up doing as Bob is advising. If they do not work, get a pair of 15" rims and and run the 235/60-15 DRs at the track. On the street you will need those DRs unless you like showing how you can spin tires . However, I wonder how much better the newer BFG DRs are in the wet and tread wear? The older ones were horrible.

Actually, there are 3. The smallest one has smaller pipes pointing straight forward. Its OK for a mild upgrade. The medium-size is the most popular. It is physically bigger than the small one and has 2 7/8 pipes angling up and out slightly. The larger and most desirable has the same shape as the medium but is coated black, is taller and has less but much larger tubes. Here is a pic of the medium and large.

I-75 runs through Gainesville. The locals (I assume Rick Bowers, Jeff and myself) will finalize arrangements soon. Nice car.

It is fiberglass and I got it horse-trading with a buddy. It needed a little work.

http://www.hybridz.org/cgi-bin/ultimatebb.cgi?ubb=get_topic;f=10;t=001274

Fred, thanks for the kind words. Reading about it is great but being in the middle of it is better, so come on out and join us. A couple of us are planning on going up to Gainesville this Saturday to join the G-ville club in a show. Why don't you come on out and join us?

Jens, is your intention to convert the carb setup to a late EFI & I/C setup or just try to get the most of what you have? Here is an article that might help you understand the evolution of this engine. http://gnttype.org/general/v6hist.html Also peruse this site for more info than your brain can probably absorb . Click on the drop-down for Technical Articles. http://gnttype.org/techarea/techpage.html

This is what I have been trying to tell folks all along. If you step it up to 3", then you have to put 2 sharp 90* bends in it and I doubt that is any better than a 2.5" with 2 45* bends. Amazing this hangup with wanting a 3" DP on the stock t3 wastegate that has a 2 1/8" id outlet.

Are you referring to th eold carbureted ones of the "hot-air" ones? Not worth dealing with the old carb setup. The hot-air has potential but no where close to the I/C'ed version and if you want to match the performance of the I/C'ed version, it will not be cheap. However, it all depends on what it is in and how much power you are looking for. Here is an artice on how to hop up the "hot-air", which had the turbo bolted directly to th eintake with no I/C. http://gnttype.org/techarea/recipes/hotair3.html

Drool! I think I showed some pics a while back. Is the block worth $3500? What is a flyweight aluminum block that can support 2000hp worth? The Buick crowd is waiting anxiously. The current StageII boys will upgrade and hopefully that will bring the price of the iron StageIIs down to a reasonable price where everyone afford to build a 1000hp street car .

Are we building a car or an engine to go hi-10s for $5K? If we are talking drivetrain, that's not difficult with the Buick 3.8L turbo simply because you only have to focus on bolt-ons. The reason I am posting though is how I notice Bob's advice going unheeded, and not a single mention of the budget needed for the chassis, brakes and suspension upgrades needed to drive a 10-sec Z car on the street. Think a 12-sec Z car is fast? Try one that can do 0-60 in 2.34 and 0-100 in 6.15. Sounds cool? NO! Its downright scary and if you do not respect it, YOU WILL KILL YOURSELF!!!. I don't care how many fast cars you have driven, you are having a death-wish if you build a 450-500hp Z car w/o dumping BIG $$$ or have an innovative way to strengthen the frame and upgrade the brakes and suspension. I cringe every time I see Darius' videos because everyone thinks what he does is cool. To reiterate, he has a death-wish. I try everything in my power to avoid any kind of wheelspin to the point of using 275 DRs as my street tires. RESPECT! IMO, the "cheapest" route to a 10-sec streetable car (one that can be driven anywhere, anytime, semi-economically ..)is with forced induction and the Buick 3.8 turbo and the RB2x are top of the list. You can count documented streetable 10-sec L-powered Z cars on one hand (finger? ..) with 240Z Turbo the closest and you are talking big $$$. For the Young 'uns dreaming of a monster Z car, heed the warning and advice of those who have been there, done that.

If 540lb/ft of torque launching with slicks and a t-brake has not broken it, I doubt the diff will.

Would there be any interest in an unbreakable urethane replacement mount? One is being developed as we speak for the RX-7 as theirs is just as bad especially with their hybrids. What would folks be willing to pay for something like that? That is what I am using for an engine mount to stop my torque monster from coming through the hood.

Good find.

Unless you have some upgraded hybrid with a modified T3 turbine housing, the outlet is 2 1/8". Would a 3" DP be better? Absolutely, BUT you have start with 2.5" then expand it to 3" then make a 90* bend, all w/in 4-5" or so, then another 90* to go towards the back. IOW, a 3" DP for a stock turbine has to follow the same shape as the stock DP. Someone has to convince that is better than a 2.5" that comes straight off the turbo for about 6" then makes 2 45* bends. See the pic to understand what I am saying. As for the "control" thing, that is debatable at this HP level. I ran 17psi, Z-Gad is running 19 and Patrick ran 22. None of us have/had any control or boost spike problems with our el-cheapo boost controllers, 2.5" DPs and the same turbo you have, with Patrick running 11.74 (350rwhp). I know my GNZ is different but remember I am running 25+ psi boost with an internal wastegate, adjustable wastegate rod and simple bleed-off valve. How? A simple $1 fix to put a softer spring in the bleed-off valve for better granularity, err, control. I personally think the cost of the turbo mod, new DP, exhaust mod and the external wastegate itself could be put to better use until you start exceeding 350+rwhp. Right now you are a little less than 300. But, what do I know . That external wastegate sure sounds and looks exotic though.

WHY?

Mike, that was 480RWHP. With a 18% drivetrain loss factor (that's what the GN crowd uses) that is 585hp at the crank. What James is trying to say is that our cars are even in terms of HP confirmed by the fact that the times in the 2nd 1/8-mile are even. As my car runs today, I have .7 advantage in the 1st 1/8-mile and that is hard to make up no matter how much HP you have. james has been ragging on my "baby" turbo for years and now I am upgrading to a "man's" turbo. Should eclipse 500/600 soon. Mike, WARNING, WARNING!!!! This is a STRONG ADDICTION. Somehow I have visions of you being the 1st TT-SBC HybridZ. What we are talking about here is a car capable of running in the 9s, blasting to over 200mph, and quite streetable with 20mpg. I estimate you only need 600hp to accomplish that and with a properly setup SBC, that is a piece of cake.