Wasted by GTP

This happened a few days ago, just haven't had time to post it up until now...

On the way to Kabuki's Thursday night came across a pretty good race.
We were going down 460, which is a short stretch of highway about 2 miles long before you get off to head towards the restaurant. I was riding shotgun in my friend Sean's Rx7. Also driving with us were John in his 2000 V6 Accord, and Chris in his Sentra SER Spec-V. We get on 460 and John pulls alongside us in the Accord. We all knew it was going to be a waxing but fun none-the-less. Sean lets John take off first and goes right after him. He starts off high in 1st gear, and pulls even by second, pulls about 2 cars by third, and gains another 4 through third. Slow down after that and get into the offramp lane. I look back and notice and unidentifiable car fly past the Accord and cut him off, getting right behind us. We go around the circle and come out on the street and switch to the left lane. The car then pulls up beside us and we notice it was a GTP(supercharged Gran Prix). I tell Sean that he must have seen us racing John and caught up to play. And just so happens the light ahead of us turns red. Sean givs a slight rev and the guy returns it, just a little rev. The light goes green and Sean takes off normally, thinking that the race would go from a roll I guess(don't know what he was thinking, dumbass:D). The GTP guy takes off hard and gets a bit of wheelspin, but in the process jumps a ways ahead. Sean decides to go for it at this point and hits the gas. The GTP shifts into second I guess, and that's when all hell breaks loose. I'm guessing he must have had a supercharger upgrade or something, because that damn thing drowned out our turbo, our exhaust, our EVERYTHING. The whine was sooo incredibly loud and then the things just rockets away. Couldn't race very far because of traffic ahead, but by the time we are halfway through 3rd gear, the GTP has pulled 2 cars or so. Go two more times, both from a 30mph roll or so, same outcome both times.
Am I just not familiar with GTPs? Are they that quick? Is the supercharger that loud?
Sean has a downpipe and exhaust on the Rx7, that's about it. But still, I didn't know the GTPs could run like that. I think he may have had an upgrade, but I'm not really sure...

I/H/E and new smaller pullies get that beast to near 12-13 1/4. Careful of the sleepers

Think about it, 3.8 liter EFI V6, supercharged. A little porting, and a smaller blower pully and you're making serious power. They already make 240-260 hp stock, and they are quite undertuned.

I think they have forged cranks as well, but I'm not sure. Either way, they have a lot of potential.

Originally posted by Cbass
Think about it, 3.8 liter EFI V6, supercharged. A little porting, and a smaller blower pully and you're making serious power. They already make 240-260 hp stock, and they are quite undertuned.

I think they have forged cranks as well, but I'm not sure. Either way, they have a lot of potential.

Aww, damn. That's the problem right there. I had no clue they made that much power stock. I wasn't sure but thought it was closer to 230hp for some reason. Yea, I'm thinking it was the supercharger upgrade. It was definitely loud as all hell. Either way though, the Rx7 isn't making big power. Maybe in the range of 280 or so if he's lucky.

A guy in STL has one that runs 12's all day long, I don't know what he did to it, but I can find out...

Originally posted by BlkCamaroSS
A guy in STL has one that runs 12's all day long, I don't know what he did to it, but I can find out...

Man, the GTPs have more grunt than I thought. I didn't know they ran like that stock even, so I can definitely believe 12s.

Yeah I was looking up what the Hp was on those things and found that they were 240. There torque is at 280 ft-lbs. That thing must have had some type of major up grade to his car to beat the rx7 that easily. I mean really, Rx7 stock is at 255 hp but its only got 217 torque. There could also be a possibility that he switched out that stock supercharger and gotten one from rsmracing or something like that. I mean there could be lots of different reasons.

Stock 2 Stock the X7 would work him for weight reasons. Now that guy must have done some work to his beast.

Yea that's what I'm thinking...Must have done a supercharger upgrade(smaller pulleys), or something to get some pretty good power out of it, because it definitely ran hard.

Yea, if I am not correct the stock 3.8L Supercharged puts out 240hp/280ftlbs and it uses the Eaton supercharger (centrifugal? not sure). The car is very under-specced, but they did it for a reason, they didn't want it to compete with the trans-am/firebird. However it seems for like 2005 or so, they plan on making it quite powerfull with some outrageous HP figures so far and with so nasty looking accents.

Have you seen the new Jeff Gordon Monte's, blue with ghost flames??? Not my cup of tea (and I hate Jeff Gordon)...

Yes, it has an Eaton M90 blower, which is running at a conservative 8psi... same story with the Thunderbird SC, which also had a 3.8 liter supercharged V6...

With a pulley upgrade, exhaust, and porting, you're well over 300hp, probable 350 or so. I've seen more than one 11 second GTP.

http://www.clubgp.com/cgi-asp/qtrmile.asp

maybe that sudden loudness after shifting into second coming from the STP was a shot of laughing gas...??

How much do they cost now?? I bet they're gonna cost a GRIP in 2005.

Originally posted by fatninja19
maybe that sudden loudness after shifting into second coming from the STP was a shot of laughing gas...??

How much do they cost now?? I bet they're gonna cost a GRIP in 2005.

No, I meant the supercharger got LOUD. The car was pretty loud too but it was the supercharger whining that was so damn loud. Don't think it was nitrous because of the lack of wheel spin. Unless it was a really small shot, it should have given him spin on his little street tires.

I'm quit unfimiliar with nitrous.... does the engine get loud when one squeezes?

Originally posted by fatninja19
I'm quit unfimiliar with nitrous.... does the engine get loud when one squeezes?

Yes, but not because of the nitrous...It may get louder because the nitrous accelerates the car faster and runs it up into a higher RPM quicker, which would make it loud. But the nitrous itself doesn't make and "noise" or anything like that.

Last year when I went to the track, there was a GTP running 12's. With the stock pulley he was running high 15's low 16's I believe, but once he swapped the pulley he was running high 12's very low 13's. Depending on how well he hooked and shifted.

Well, you can't just swap the pulley and expect to pick up a few seconds like that, you have to have the engine flowing well enough or you'll be blowing head gaskets all over the place.

Like I said, porting, exhaust, a chip would help also, and a small blower pulley. Simple math, the smaller the supercharger pulley, the faster the supercharger will spin. The 3800 S2 SC uses the M90 twin screw type blower, which developes good boost at low rpms, and off throttle idles, making for good fuel economy.

The downside is, the GTP is fairly heavy, and it's front wheel drive...

Originally posted by Cbass
Well, you can't just swap the pulley and expect to pick up a few seconds like that, you have to have the engine flowing well enough or you'll be blowing head gaskets all over the place.

All I know is that he swapped a pulley, and lost a few seconds. I don't know what else he had done for mods, but I witnessed his runs first hand. I don't remember the exact times he ran, but its was a big difference. I think it was high 15's to mid 13's, the more I think about it.

What year RX-7? I know GTP's were fast but damn, RX-7 is pretty mean too. Pully swap is a definate possibility, one of the most frequent upgrades usually done first, makes quite a difference. The think that suprises me is the fact that it was sooo loud. I'm familiar with hearing them alot but didn't think they were ferocious in sound. He had to do something. If you would like to know more about their 1/4 times and such, i know a really good site of a few GP tuners and what they run. Don't know if that guy was runnin about the same.

http://www.migpc.com/Members/members.html

Originally posted by pontiactrac
What year RX-7? I know GTP's were fast but damn, RX-7 is pretty mean too. Pully swap is a definate possibility, one of the most frequent upgrades usually done first, makes quite a difference. The think that suprises me is the fact that it was sooo loud. I'm familiar with hearing them alot but didn't think they were ferocious in sound. He had to do something. If you would like to know more about their 1/4 times and such, i know a really good site of a few GP tuners and what they run. Don't know if that guy was runnin about the same.

http://www.migpc.com/Members/members.html

The Rx7 is a 95. Yea this supercharger was DEFINITELY aftermarket or at least upgraded. I was walking to my car just yesterday and a GTP passed me going full out. The supercharger whine on it was minimal to non-existant:p The one we raced in the Rx7 most definitely wasn't stock.

Originally posted by Self


The Rx7 is a 95. Yea this supercharger was DEFINITELY aftermarket or at least upgraded. I was walking to my car just yesterday and a GTP passed me going full out. The supercharger whine on it was minimal to non-existant:p The one we raced in the Rx7 most definitely wasn't stock.

Yea, it couldn't have been stock with such a sound. There is a company called SLP that makes performance parts for a few GM performance cars, you probably know of them with your z/28. I just today put on a new SLP CAI air box, and i definatly notice a big difference in sound. Kinda had me worried for a minute there. I could imagine that the supercharger would have been even louder. Did the GP have a twin air scoop hood? If he did it could have even been a Grand Prix GTX which im not really that familiar with. They are a pretty rare find.

Hey guys. I am a GTP owner. The whine of the supercharger gets loud with light modification. Once you do a cai you notice the whine. If you go to a smaller pulley then it screams. I get many weird looks at wot. The whine is much louder at higher rpms. You don't really hear it in first too bad, but it screams through second. GTP's typically run mid 14's bone stock. There are some freaks that run low 14's, and some slow ones that run high 14's. If someone is in the 15's they are doing something run. There are some GTP's with the same mods as mine that have broke into the 13's. If you have money to spend they are good for twelves all day. There are some in the low 11's, but I have not seen a 10 second one yet. The stock pulley is a 3.8. With a couple mods you can go with a 3.4. A couple more and then 3.25 and so on. You have to open up the exhaust though or you will just be stacking the boost. Some people get as small as 2.8 with their pulley. There are even some running a little smaller than that. The M90 is a belt driven roots supercharger. You have full boost very easily with no lag. This creates some traction issues, but once you get good at a rolling launch you can really surprise some people. They make for great little sleepers, so look out for one in a neighborhood near you.;)

Hey, what's up guys. I've been on the board just reading for a while now, but never registered. I also own a GTP. 1999 to be exact. Check out my sig, that's what I read with JUST a K&N. A lot of the people over on ClubGP call my car a freak because of what I've done.

A smaller pulley is on the way, then I'll start fooling with the exhaust a bit. By throwing on a FWI or CAI, you can really hear the S/C scream. However, like others have said, it only gets louder with smaller pullies.




Oh, and to correct something someone said earlier. They are Eaton M90s, but they are not twin-screw, they are roots-type superchargers. Similar, but close. :)

Yes, it has an Eaton M90 blower, which is running at a conservative 8psi... same story with the Thunderbird SC, which also had a 3.8 liter supercharged V6...

i never knew that the ford and gm v6 was the same:rolleyes:

Originally posted by TheDirtyLittleMan


i never knew that the ford and gm v6 was the same:rolleyes:

They aren't. There are several differences between the two. I know a kid that has a lightly modded super coupe, and it does not keep up with the GTP. I think the Ford engine has some good horsepower numbers, but is a little weak on the torque side. Also the GTP is only running 6lbs of boost from the factory. Once you do a pulley swap you are more in the 8-10lb range.

Take care,

David

Ford and GM 3.8 V6 the same? Right.

The 3800 Series II is actually a Buick engine, and its "ancestor" is the 3.8L V6 engine that powered Buick GN's. Of course, those Grand Nationals were turboed instead of blown.. and GN's ran 13's stock in the 1980's http://www.gnttype.org/

DRSully, I believe the boost is 7.5 max at 6k RPM, with the stock 3.8 pully.

The supercharger is pretty quiet on the GTPs. If his was whining loud, he definitely had replaced the pulley to a 3.25" or less (from 3.8" stock). Our cars are very easy to put in the 13s. Intake for $300, exhaust/new downpipe for $600, new pulley for $70, shift kit for $100, you're talking high 13s for around a grand, or so I'm told. My new pulley and intake are going on in the next week or two, I'll keep everyone posted as to the upgrade if you're interested. I'm told that the 3.4" pulley I'm getting alone could increase boost from 8 to 10psi and up to 20 hp. I meant that it is 8psi stock and goes up to 10, not that it'll give me 8-10 more psi (just re-read that and saw how it sounded).

The whine on mine is very noticeable and I only have a 3.4 pulley. I think open cones make it much more noticeable. I have heard of some GTP's getting 7.5 lbs stock, but I thought must stayed around 6 and sometimes 7. It may take some $1k to reach 13's, but some do it for much less. There is a thread running on www.clupgp.com right now about someone that has $150 in mods and is running 13.9. That is in a four door as well. I know everybody does not get there that easy, but it seems like we have quite a few like that. A guy that used to own a GP is over on the forum as well. He ran 13.5's with nothing more than a couple hundred dollars in mods. The potential is great for these cars. It is all about the right combination. You should expect 9-10 lbs. with a 3.4 pulley.

Take care,

David

Hey, I have a 98 GTP. My best time (in my sig) was done with $300 dollars in mods. People that know GTPs know that with Race Gas/Low tire PSI/no spare/no jack and a 2.00 60' I would hit 13.7s easily.

My mods:
$70 - 3.4 S/C pulley
$225 - Used 1.9:1 INTENSE Rockers
$5 - Local used Fenderwell Intake.

The Scream of the supercharger is EASILY heard after JUST an intake. A stock one is Very quiet/muffled/choked!

Hey, my sig is wrong! That time was done with a 2.1 60'

does anyone have hte max psi listings for the other pulley sizes
and the external dimensions of the supercharger.

one last question, do you know if its possible to switch the side that the pulley is on? possibly by flipping the front cover, or would that not work? and if you flipped the rotors, wouldnt that just turn the pumping direction around?


anyways, thanks guys :D

Originally posted by Cbass
Think about it, 3.8 liter EFI V6, supercharged. A little porting, and a smaller blower pully and you're making serious power. They already make 240-260 hp stock, and they are quite undertuned.

I think they have forged cranks as well, but I'm not sure. Either way, they have a lot of potential.

The new 2004's come stock with 260 HP. anything '96-02 has 240 HP stock.

All GTP's have forged cranks, there aren't to many that dont anyway.

Originally posted by non sequitir
Ford and GM 3.8 V6 the same? Right.

The 3800 Series II is actually a Buick engine, and its "ancestor" is the 3.8L V6 engine that powered Buick GN's. Of course, those Grand Nationals were turboed instead of blown.. and GN's ran 13's stock in the 1980's http://www.gnttype.org/

DRSully, I believe the boost is 7.5 max at 6k RPM, with the stock 3.8 pully.

The Ford version of the 3.8 V6 is very poorly made unlike the GM version though.
All we need is a newer sportier Buick and i'll be happy in life.

The max psi you can run efficiently is in the 10-12 range. Anything more than that and odds are you are just stacking boost.. Even GTP's running small pullies with supporting mods are in the 8-10 range due to very free flowing exhaust systems.

I have never heard of anyone switching the side of the snout of the supercharger. Most intake systems for a GTP take the air from behind the driver side headlight (other than a fender wall intake). If you switched the snout to the driver's side, you would be forced to switch the intake to the passenger side. The battery sits behind the passenger side headlight, so it would create issues with getting cold air to the engine.

GTP's only have 240hp in the 97-03 model years. The 96's were the 215hp dohc 3.4L.

Take care,

David

97-03 Grand Prix GTP's have 240hp and 280lb.ft. right out of the box. I have not done that much work to mine and am running low/mid 13's. These cars stock will laugh at a stock Mustang GT 80's/90's up to 98. First time I ever ran my car stock was in april on about a 50-60 degree night/no wind with about 20k on my engine and hit a 14.8 They are deceivingly fast and with minor mods plus a good tire the low 14 second mark is easy to get to.

Wow, this is an old thread.

My brother dynoed his gtp with intake, exhaust, 10psi supercharger pully, and digital horsepower pcm. He made 220hp, and 290 lb of torque. His mods were suppose to put him at 290 crank so the driveline loss is pretty bad. BTW his old tranny crapped out on him, and this one had 1000 miles on it. Roller rockers, and lifters are suppose to free up all types of power for the 3.8 though.