If I bought a ProCharger D1SC for my 1992 Trans Am GTA what kind of gains interms of HP and quater miles times would I see? also please try and give me number estimates and also tell me how much boost you estimate is based upon.

To see my current mods, just click on the SLP package link in my sig. My current quater miles time is also in my sig.

I'm asking because basically if I can't pull a 12.0 sec time then I have other things to spend the money on right now. I just want to know your guys opinions.

Thanks!

 

ATI warns against using the D1sc kit on a 305, this is a dyno sheet of the 91 with the same complete exhaust as you have (1 3/4" slp and cat back), hollow cats, P-1sc, 3core intercooler and a slipping belt. the #'s indicated must be disregarded due to the fact that they are a shift spike follow the curve instead (about 300rwhp/325 tq). this car did make more power later but did not get a chance to dyno before I bought it and started dissasembling it for a blown head gasket (crappy gas) and then a rod knock (a month of him driving it around with antifreeze for oil). at the street races his dad had fits because the ZO6 could not get around him.

 

Ok, now I can still run a D-1SC on my 305 if I just keep the boost down a little right? I want to buy a D-1SC because later I plan on being able to use the same SC on a 406 SBC.

 

also how rare do you suppose my friends car is, same as yours but convertable.

 

ATI warns against using the D1sc kit on a 305....

They never warned me..... I wonder why? I've been D1SC'd almost two years now and producing boost levels unimaginable by most. My lastest runs produced 14-psig and am now pullied for the most rpm's the D1SC can turn. I should see in excess of 16-psig. Please keep in mind that I run 9.22 to 1 C.R., use twin IC's and water/alcohol injection.

....and a slipping belt.

How much boost did it create on this dyno run?

....at the street races his dad had fits because the ZO6 could not get around him.

Gotta love it!!!


92GTA,

If you're already running 13.7's, I'd say a 12-flat is not unrealistic based on the improvements I've seen on my 305 with the D1SC.

 

Well they didn't make convertible GTA's in 1991 and 1992 so it can't be just like my car but a 'vert. Assuming it's just a regular Trans Am and a 1992, they didn't make very many but they are everywhere. If you go on Autotrader and do a search for 1992 Trans Am's just about all are 'verts so right now they are not all that rare or special considering you can buy one anywhere....

Sweet! Thanks Willie! I might contacting you or mypontiac to see how the dual intercooler system is fitting to his Trans Am. Now to get that 12 flat would I have to run the water/alcohol injection or what would I get if I did add that and increase boost?

 

his must not be a GTA then. the car only made peak 6-8 psi and later off the dyno made peaks of 11-12 and 1.6 rockers were installed later also. it was Cary at ATI that said that, but I still sold one to the member of this board with his 305. I havent heard from him to see how he is doing now. I'm sure it would run nicely but I think Cary just wants to make sure the customers are happy. now I have to send the P1sc from the car I just bought in to get the D-1sc upgrade (almost $1000) changeover so I will have some kind of boost on the 412.

 

Sweet! Thanks Willie! I might contacting you or mypontiac to see how the dual intercooler system is fitting to his Trans Am.

Sean (aka mypontiac) received his D1SC with twin IC kit last week. ATI did not package everything he needs and sent him some parts he won't need. So it will be at least a couple more weeks until he gets all the correct parts.

Now to get that 12 flat would I have to run the water/alcohol injection or what would I get if I did add that and increase boost?

My experience is that up to about 8-psig boost, all you'll need is an intercooler. You won't even need to retard timing with boost. So the question becomes will you gain 1.7 seconds with "only" 8-psig boost? I don't know for sure, but my guess is that you won't. I gained two seconds with about 12-psig but again, you may not get the same results. At 12-psig, intake air temps start to rise substantially, BUT it is still not at the level where anyone should be alarmed. It's on the order of 150 degrees in the plenum. But personally, I use the water/alcohol at this level of boost, which reduces that 150 degree air down to 85 -90 (on a 100 degree day). I KNOW detonation is not an issue with these air temps, whereas at 150, it does become a concern (in my eyes).

I think the only way you'll know how much boost you'll need to gain the 1.7 seconds is to install the kit and start on the safe side. Gradually increase blower speed by changing pullies until you've attained your goal!!!

On my latest 14-psig runs, I wanted to play it safe. Here's my specs:

1) 35 degrees spark advance at WOT,
2) One degree of retard per one pound of boost starting at 10-psig, &
3) 40/60 water/alcohol at 3-psig and above.

Before I start dinking with the above settings, now that I'll be running 16-psig or more, I need to complete and install a wide-band O2 -- it is almost complete. Once I determine air/fuel ratio, I will begin playing with the above, initially by reducing the amount of spark retard vs. boost. I will also experiment with water/alcohol nozzle sizes because I understand too much water hinders power. Most of this experimentation will be done on a dyno.

Willie

 

Willie, thanks. That was very imformative. I think I'm going to hold off until I can rebuild my factory tranny and improve some other factory drivetrain components before I start trying to go too fast...

 

I think working on your drivetrain first is the smart thing to do. Although in my case, I ended up doing my tranny last. I lost third/overdrive on my way home from the track; the night I ran a 12.04. But I knew at that time the tranny was my weakest link -- it was only a matter of time.

I should have mentioned above that with the D1SC, there is no question you can gain 1.7 seconds. This blower is an excellent work of art -- it produces a LOT more air than I'd imagined -- proved this to myself by disconnecting the outlet with the engine idling and standing in the airstream. It's like sticking your head out your window at 40 mph!! The only unknown in your case is how much boost you'll need to make to get that 1.7 seconds.

Willie

 

I just had thought. If you use a water/alcohol injection mix to cool the air from 150 to 80-90 degress, what if you were to use a tiny shot of nitrus to cool it?

 

....which is exactly what I did when I owned my Paxton. I "augmented" it by adding a 50-shot of N2O. The general rule of thumb is a one-second improvement equals 100 hp. So this additional "boost" should have resulted in a 0.5 second improvement. It was better!! I gained 0.8 seconds. When I would use the N2O, I did not use the water.

The problem with my old setup was the rpm limitation of the Paxton. I could create only 6-psig boost with it and reached impeller redline about 800 rpm's before my engine redline, so I could not maximize my engine's potential.

The one unknown with my old setup was how much lower the intake air temps were with N2O. Also, I did not have an intercooler either, so..... your guess is as good as mine.

Although using N2O with the blower is a good idea, I feel you'll get more than you expect (in lowering E/T's) with the ProCharger. As before, step into "the power of a blown engine" gradually. If you don't achieve your goal (and you will) with only the blower and the "need for speed" just won't go away, then do the N2O. (Heck, you'll be in the 11's with just the blower and maybe water.)

FYI, my best without the blower is a 14.06 and with is a 12.00 (to date -- more to come), so you're faster than I am, relatively speaking.... and I don't need no stinkin' nitrous, so I don't think you will either!! Sorry about the last two paragraphs. Although I'm typically serious on these boards, I do exhibit a lighter side once in a while!!

Willie

 

Right on then! Sounds like I have a plan going. 11's here I come Of course I estimate it will cost me about $4-$6K to get there in terms of building up my drivetrain and getting everything I need

Thanks allot willie!

 

Glad to share my experiences....

$4k - $6k may sound like a lot, but it sure beats new car payments on a car that's depreciating like a rock falling off a cliff. And you'll be LOTS faster too!! Now you guys know why I drive my extremely loud 15-year old car when I could be driving a new LS1.... I know what my neighbors are thinking, "Grow up!!" Heck, I was married when I was 27 (that was 18 YEARS AGO) and have one daughter. I should "act" my age, I'm sure they're all saying. Ahhh, forget what the neighbors think!!!

Willie

 

Hey I hear that, I'm married and have a son and I love not acting my age! For me though it's not even so much of the value stand point but just the simple love for the car which I'm sure you can relate to as much as any other true car guy on this board.

I could have a new 2002 Firehawk if I wanted to but I love putting money into my 1992 GTA and I just bought a 1984 15th Annv. Trans Am to restore, I sold my 1991 GTA to buy that. My 91 was going to be my BIG project with a 406 stroker and a D-1SC, rool cage, loads chassis mods, but I figure what the hell, I'd rather restore a new classic than hack up a perfectly stock car and a somewhat desireable car. Now with my 92 I just plan on putting on a ProCharger for kicks and then when I do get another project car I can still use it on that. I don't really want to do anything to the 92 that can't be undone down the line you know. I'll most likely just rebuild the tranny, install the D-1SC kit and go with that for now.

Talk to you later, Alex.