Thread: Advice Needed on Stock Supercharger

^yes...and no. I for one believe that the stock cat is a restrictive SOB, and that the exhaust tone doesn't suffer much from removing it - as compared to the resonator. As for actual # gains...not so much, but if you're going to start dropping pulley sizes - you need to FIRST invest some money into the exhaust - ie; u-bend removal, and larger downpipe...if you're going to do that...get rid of the cat or go with a hi-flow cat at the same time...it just makes sense.
HP gains from porting the inlet/outlet of the blower (virtually none, BTW) will always be argued, but there is no disputing the fact that it makes the blower more efficient and that is a good thing. Lowering the outlet temp is very useful for future pulley drops and tuning.

My standard reply to fairly cheap and easy instant HP gains:

NOTE: You can find all of this used - check the For Sale section for demods, etc.

1) Delete the U bend, upgrade to a downpipe and remove the cat entirely or get a DP with a hi-flow cat. Avg. cost - $125 - $200
2) Get a set of 1.9 roller rockers and 105 lb springs. Avg. cost - $225 - $300
3) Drop spark plugs to one step colder, ie; Autolite 104's. Avg. cost - $20
4) Drop pulley size to 3.5", not 3.4. This might be harder to come by - it isn't a popular size and is usually a press-on style, where modular would be ideal. Avg. cost - $25
5) Tune, tune, tune. Nothing you bolt on, press on or remove will matter at all, if you don't tune the car afterwards. Avg. cost - Free/12 pack, etc...if you can find someone to help you out that has a tuner.
6) BONUS - if you can afford it - get with Trannyman95 and get 3.29's, a hardened 4th gear(not for performance, but longevity), and a shift kit installed. IMO - the BEST bang for the buck mod for these cars. You have to drive one with these to understand. Trust me.

Nick's (bluegtp91) post has just about everything you need in it. But the real simple rule of these cars is - they need to breathe, and they need to be tuned.

-Swash

Originally Posted by Swash

^yes...and no. I for one believe that the stock cat is a restrictive SOB, and that the exhaust tone doesn't suffer much from removing it - as compared to the resonator. As for actual # gains...not so much, but if you're going to start dropping pulley sizes - you need to FIRST invest some money into the exhaust - ie; u-bend removal, and larger downpipe...if you're going to do that...get rid of the cat or go with a hi-flow cat at the same time...it just makes sense.
HP gains from porting the inlet/outlet of the blower (virtually none, BTW) will always be argued, but there is no disputing the fact that it makes the blower more efficient and that is a good thing. Lowering the outlet temp is very useful for future pulley drops and tuning.

My standard reply to fairly cheap and easy instant HP gains:

NOTE: You can find all of this used - check the For Sale section for demods, etc.

1) Delete the U bend, upgrade to a downpipe and remove the cat entirely or get a DP with a hi-flow cat. Avg. cost - $125 - $200
2) Get a set of 1.9 roller rockers and 105 lb springs. Avg. cost - $225 - $300
3) Drop spark plugs to one step colder, ie; Autolite 104's. Avg. cost - $20
4) Drop pulley size to 3.5", not 3.4. This might be harder to come by - it isn't a popular size and is usually a press-on style, where modular would be ideal. Avg. cost - $25
5) Tune, tune, tune. Nothing you bolt on, press on or remove will matter at all, if you don't tune the car afterwards. Avg. cost - Free/12 pack, etc...if you can find someone to help you out that has a tuner.
6) BONUS - if you can afford it - get with Trannyman95 and get 3.29's, a hardened 4th gear(not for performance, but longevity), and a shift kit installed. IMO - the BEST bang for the buck mod for these cars. You have to drive one with these to understand. Trust me.

Nick's (bluegtp91) post has just about everything you need in it. But the real simple rule of these cars is - they need to breathe, and they need to be tuned.

-Swash

why do you say go with the 3.5 vs. the 3.4? How much HP are you really losing out on with .1 inches here?(assuming it is tuned)

Originally Posted by Liquifire

why do you say go with the 3.5 vs. the 3.4? How much HP are you really losing out on with .1 inches here?(assuming it is tuned)

It isn't about the HP you're "losing" - it's about the KR that you're not gaining. A 3.5 can actually give a higher gain in HP because of the lack of KR that comes with it. Case in point - if you currently run a 3.4 with 0-2* of KR at WOT - and say you run 13.9-ish. If you take that same car and put a 3.3 or 3.25 on it - you will likely run slower - because the increase in KR that is going to rob HP. In my '02 GP I had 1.9 RR's, 105# springs, 3" DP, PEM's, FWI, NGK plugs, ported SC and ported TB, 3.29's and shift kit - all on a fresh rebuild that ran a 14.0X on a 3.4 pulley on a 90* and humid day - it would have run 13.8X easily, but I forgot to turn on performance shift in the PCM . It had a DHP v1.0 tune with only trans tweaks to accomodate the 3.29's. I had only blips of KR at WOT, so I decided to drop to my 3.25 and run. I ran almost .2 slower - and had 4*-6* of KR at WOT. With the 3.4 - had I had perf shift enabled - I would have seen 13.8X at 100+ without anything more than a canned tune. With further tweaking, I would have been able to drop to a 3.3 or 3.25 and gotten to maybe 13.6X.

The point I'm trying to make is - there are a lot of cars out there that pop soon after a 3.4 pulley is installed. It's the most popular "instant gratification" mod out there and damage occurs mostly due to ignorance as to the potential consequences. A 3.5 will still provide a noticeable gain - without the huge jump in KR that typically comes with a 3.4.

Getting off my soapbox now...

-Swash

Originally Posted by 98gtpne

thanks for the replies. I have already orderd the 3.4 pully and new belt and the new plugs and wires so i guess i will get the dp next and then take it in and get tuned.. im really just looking for 25hp more then stock for little more power since this is the daily driver. maybe someday i will get crazy and put alot ot time in money in it but for now i just need it quicker cause it was really slow all stock..

It has to breathe first.........you will NEED a downpipe and PLOG or headers first(before the pulley) otherwise you will just have crazy KR and pulled timing up the A$$....Also have the PCM installed at the same time or you will not be realizing any power potential that you will have...........fwiw.

Originally Posted by Swash

It isn't about the HP you're "losing" - it's about the KR that you're not gaining. A 3.5 can actually give a higher gain in HP because of the lack of KR that comes with it. Case in point - if you currently run a 3.4 with 0-2* of KR at WOT - and say you run 13.9-ish. If you take that same car and put a 3.3 or 3.25 on it - you will likely run slower - because the increase in KR that is going to rob HP. In my '02 GP I had 1.9 RR's, 105# springs, 3" DP, PEM's, FWI, NGK plugs, ported SC and ported TB, 3.29's and shift kit - all on a fresh rebuild that ran a 14.0X on a 3.4 pulley on a 90* and humid day - it would have run 13.8X easily, but I forgot to turn on performance shift in the PCM . It had a DHP v1.0 tune with only trans tweaks to accomodate the 3.29's. I had only blips of KR at WOT, so I decided to drop to my 3.25 and run. I ran almost .2 slower - and had 4*-6* of KR at WOT. With the 3.4 - had I had perf shift enabled - I would have seen 13.8X at 100+ without anything more than a canned tune. With further tweaking, I would have been able to drop to a 3.3 or 3.25 and gotten to maybe 13.6X.

The point I'm trying to make is - there are a lot of cars out there that pop soon after a 3.4 pulley is installed. It's the most popular "instant gratification" mod out there and damage occurs mostly due to ignorance as to the potential consequences. A 3.5 will still provide a noticeable gain - without the huge jump in KR that typically comes with a 3.4.

Getting off my soapbox now...

-Swash

what exhaust mods did you have with your 3.4 setup? Just curious because I was going either PLOG or headers with DP and never plan on going beyond the 3.4 setup. Assuming you have no knock it would be safe on a 3.4 in your opinion? So basically just using a 3.5 to play it safe. I am completely stock on the pulley and never have any knock yet......always O.O........good for now.

Saw you had PEM's and DP........missed that the first time around....Do you think you would have any KR if you had either headers or PLOG?

Originally Posted by 98gtpne

not gona lie sounds like way to much work for a high 13

??? The only internal change was rockers and stiffer springs...about a 1 1/2 hour job. The other stuff...that's just how it should have been - GT's have 3.29's - the GTP's should have, too, but they didn't because of MPG impacts (that and they knew the trans was a turd), porting that was done wasn't so much for HP gains - but for ease of tuning and effeciency. The FWI and exhaust changes were something that I would have done to increase MPG as well as support any performance mods. So - really - not much "work" at all for a +1 second 1/4 mile improvement.

-Swash