OK, so I'm not exactly rich.. I'm pretty damn poor, and I'm debating in my head the most cost-effective way to get some more power out of my car.

I was thinking, if I dropped 12:1 compression pistons in with NO other mods AT ALL, first off what kind of problems would I be facing, and secondly, what kind of HP would I be looking at?

If it is 150WHP, I would be happy imo.

Also, I plan on running a large shot of nitrous, prolly around a 100 shot. Would there be any problems with a 100 shot and 12:1 pistons?

OK, the second, probably more feasible option for me, is to drop in 8.8:1 turbo-ready forged pistons. I know this will make the car slightly slower, but how much slower? Are we talkin 50+ HP loss, or just a bit? If it's just a bit, I would prolly do that and run a REALLY large shot of nitrous, say like 150? Can that be done?

Then really really far into the future I would have the option of turboing. But I can't come anywhere near being able to afford a turbo right now.

Opinions?

Check out the high compression post in the advance section. The cliffnote version, the dude is has 12:1 and is detonating like crazy, and that's with many supporting mods. So 12:1 takes a ton of cash. 8:8, it will be noticeably suggish. I think (NOT SURE) it is a 4% loss in hp for every compression point – that's why you up the boost to make up for the loss. I'd go with 10:5 to get peppy performance and call it a day imo.



-------jezreel
1998 GS with hrc stage 2, sfmu, ml, prokits, egt, boost gauge, apexi tt, haydans tranny cooler, costum dp, dr. uber groundwires, dynotune fp gauge. gst muff, turbo spoiler
Boostin since Aug 03.

nothing like driving with the windows down and the music low: i love hearing the turbo spool, swwwhhhttt!!!!
thanks for www.kaptainmyke.com for the sig hosting :thumbsup

go with 10.5, also low compression and nitrous is a no no. it is low comp=turbo...hi comp=nitrous. while ur at it, you should get some rods too along with the pistons.

If I go 10.5 and get rods to go with it, will I be able to turbo later on if I wanted? Or would I have to do the 8.8:1 piston dealie?

stock compression+turbo is good enough....higher than that plus boost would be insanely tuff to tune

Hmm.. so maybe my best bet is to just rebuild the engine with tough standard comp pistons and rods and nitrous the HELL out of it, then if I wanted, I could turbo later on?

Originally posted by BRU_ce
Hmm.. so maybe my best bet is to just rebuild the engine with tough standard comp pistons and rods and nitrous the HELL out of it, then if I wanted, I could turbo later on?

But they don't make a stock compression forged piston.

If you don't have the money for mods dude then don't start with pistons.


If you want a quick daily driver that will occasionaly hand someone it's ass for cheap get 10.5:1 forged pistons with some good rods, 100 shot of nitrous, and do all the bolt-ons with some hot cams.

Making these cars faster isn't cheap bro.

Originally posted by a_miller_76
Making these cars faster isn't cheap bro.

Yeah, unfortunate but true :(

I want a turbo so bad, but in my financial situation, it ain't happenin' for a LOOOOOOONG time.

IMO, bolt ons are a waste of money. For example, a CAI costs around $275 and nets you absolutely NOTHING in real world performance, same with exhaust for $600. I mean, really... are you going to even begin to notice 2 HP somewhere in the powerband?

Now, take that $275 from the CAI and $600 from the exhaust and get new pistons and rods, and you will prolly get a much higher increase in power than both of those bolt-on mods combined. I am just guesstimating, but wouldn't you have about 165 or so HP at the crank with 10.5:1 pistons? So I'm just guessing, but an increase of 25-30 crank HP as opposed to MAYBE 8 or 10 with the bolt ons.

I don't have any bolt ons because I just truly see it as a waste of money. I want to run and dig right into the engine and do some real modifying but keep the cost relatively low. I figure replacing the pistons would be the most cost effective N/A mod I could do for the price... and if I could run a HUGE shot of nitrous I could make near 250HP for short runs and be able to keep up with the "real" cars... if only for short bursts at a time

Originally posted by BRU_ce

Originally posted by a_miller_76 Making these cars faster isn't cheap bro.

Yeah, unfortunate but true :( I want a turbo so bad, but in my financial situation, it ain't happenin' for a LOOOOOOONG time. IMO, bolt ons are a waste of money. For example, a CAI costs around $275 and nets you absolutely NOTHING in real world performance, same with exhaust for $600. I mean, really... are you going to even begin to notice 2 HP somewhere in the powerband? Now, take that $275 from the CAI and $600 from the exhaust and get new pistons and rods, and you will prolly get a much higher increase in power than both of those bolt-on mods combined. I am just guesstimating, but wouldn't you have about 165 or so HP at the crank with 10.5:1 pistons? So I'm just guessing, but an increase of 25-30 crank HP as opposed to MAYBE 8 or 10 with the bolt ons. I don't have any bolt ons because I just truly see it as a waste of money. I want to run and dig right into the engine and do some real modifying but keep the cost relatively low. I figure replacing the pistons would be the most cost effective N/A mod I could do for the price... and if I could run a HUGE shot of nitrous I could make near 250HP for short runs and be able to keep up with the "real" cars... if only for short bursts at a time

Heh, reserch young one.


Each point you raise compression will yeild you 4% total power at the crank. So going from 9.6-10.6 will get you 4% hp. 140+4%=145.6 hp. You'll get more than 5.6 hp from exhaust, udp, and intake. It will cost you less in the end. Remember you can't just buy pistons and put them on in 15 minutes. Either you'll incure a lot of down time or spend a lot more money getting them installed.

Bolt ons aren't a waste of money at all, because when you ad major power adders like Turbo's or n2o they are required. Ask any turbo guy on here if they could get good power with the stock exhaust system.

Originally posted by a_miller_76
Ask any turbo guy on here if they could get good power with the stock exhaust system.

Tell me about it :cry

IMO, I am glad I only spent $400 on bolt ons (iceman, and loud-ass muffler I got rid of). Went straight to saving for turbonium. Now I am saving for the hi comp rebuild with boost hehe...


-------jezreel
1998 GS with hrc stage 2, sfmu, ml, prokits, egt, boost gauge, apexi tt, haydans tranny cooler, costum dp, dr. uber groundwires, dynotune fp gauge. gst muff, turbo spoiler
Boostin since Aug 03.

nothing like driving with the windows down and the music low: i love hearing the turbo spool, swwwhhhttt!!!!
thanks for www.kaptainmyke.com for the sig hosting :thumbsup

Do0d. You want to pick up some decent gains for the cheap, I think I would skip the internals for now. Some ideas I have:

- 50 shot (stock can handle 75, but this is conservative)
- generic intake w/ quality filter
- GST rear section
- Neon ATX 55mm or Jeep 60mm TB
- used header
- mild cams

I think these mods will save you some money in the long run, as they are generally used parts, but they can be tweaked a bit at install to make sure they last. They would all also be used with a turbo system (except the header and intake, but they would be super cheap imo). Even the Nitrous system could be reconfigured to be an IC sprayer in the future.

Granted, these are mainly bolt ons, but they're frugal bolt ons imo. Freeing up the intake/exhaust and putting in the larger TB will definitely make a noticable difference in throttle response and exhaust note. The car will feel zippier and sound lower.

Just some more ideas for you.

one thing that i am suprised no one has mentioned yet is the fact that you will need to do some minor fuel mods if you decide to put a 75-100 shot of nitrous in your car. 30# injectors would be nice as well as an safc2. oh and as it was mentioned earlier, high compression is best for nitrous but i would stick with 10.5 over 12.1 imo.

Since no one has asked this question and it's a very important question ... what condition is your stock motor? Everyone will tell you that increased compression will net you 4% per point of compression but that is theoretical. Not every 420a motor though all are at 9.6:1 (2gnt version) will not yeild the same amount of power because of wear and tear and other issues. So if your motor has a lot of miles, reoccuring issues, or other mishappenings like eating oil then a rebuild will probably do nicely.

If your motor is in bad shape and you're not trying to go extreme on power (say around 200chp max) then go 10.5:1 pistons, stock rods (yeah you hear me stock rods ... make sure they are in good shape), and decent cams. This should net a decent increase in power while maintaining good driveability. To get the most out of it though you will need to open up the path for air to flow so a good intake and a decent exhaust/header will also help. NOS is still an option but you'll need some timing control with mostly likely anything greater than a 50 shot.

If you're motor is in good shape get some decent cams and open up the air flow. That will still net a good power increase.

I thought there were forged stock pistons...and how much harder on 10.5:1 would it be to tune for a turbo boosted application than 8:8:1 compression since there arent any stock forged pistons?(not tryin to steal teh thread)

The too emotional, pyscho, hypocritical moderator speaks truth! I made assumptions that one would not be concerned with cams and turbo if their engine ran for shit. You never know though, and Thura's right. You should be sure your engine is in top condition before hitting the bottle (or any other major power adder).

Originally posted by Steve
I thought there were forged stock pistons...

They are not generally made. I'm sure you can get them custom, but anything custom is going to be more than you want to pay.

Originally posted by Steve
and how much harder on 10.5:1 would it be to tune for a turbo boosted application than 8:8:1 compression since there arent any stock forged pistons?

I imagine it's slightly more difficult. HadesOmega has had 10.5:1CR on a turbo charged 420a for a while now. He doesn't seem to have had any major problems with it. I plan on doing the same thing sometime in the future myself. It's not that you can't do it, but most people just want to sete it and forget it. A sort of Ron Popiel tuning if you will. I doubt it's really that much harder to tune. Sure, it's more finicky as to where it wants to be set, but it's just that 8.8:1 is more forgiving should something go wrong.

Originally posted by Steve
(not tryin to steal teh thread)

Yes you were. Now bugger off. LOL :thumbsup

Originally posted by DR1665
The too emotional, pyscho, hypocritical moderator speaks truth! I made assumptions that one would not be concerned with cams and turbo if their engine ran for shit. You never know though, and Thura's right. You should be sure your engine is in top condition before hitting the bottle (or any other major power adder).

Originally posted by Steve I thought there were forged stock pistons...

They are not generally made. I'm sure you can get them custom, but anything custom is going to be more than you want to pay.

Originally posted by Steve and how much harder on 10.5:1 would it be to tune for a turbo boosted application than 8:8:1 compression since there arent any stock forged pistons?

I imagine it's slightly more difficult. HadesOmega has had 10.5:1CR on a turbo charged 420a for a while now. He doesn't seem to have had any major problems with it. I plan on doing the same thing sometime in the future myself. It's not that you can't do it, but most people just want to sete it and forget it. A sort of Ron Popiel tuning if you will. I doubt it's really that much harder to tune. Sure, it's more finicky as to where it wants to be set, but it's just that 8.8:1 is more forgiving should something go wrong.

Originally posted by Steve (not tryin to steal teh thread)

Yes you were. Now bugger off. LOL :thumbsup

OHhhhhhh I thought hades had stock compression...well that fixes everything..I wanted to do the 10:5:1 but wasent sure...guess thats whats commin then.

Originally posted by Avenger
Since no one has asked this question and it's a very important question ... what condition is your stock motor? Everyone will tell you that increased compression will net you 4% per point of compression but that is theoretical. Not every 420a motor though all are at 9.6:1 (2gnt version) will not yeild the same amount of power because of wear and tear and other issues. So if your motor has a lot of miles, reoccuring issues, or other mishappenings like eating oil then a rebuild will probably do nicely.

Well, the engine is in pretty good condition... it does burn a bit of oil but nothing drastic, and it has 118,000 miles on her. The previous owner must have treated her VERY nicely but I beat the shit out of the poor thing, hehe.

I was just thinking, is it common to see used turbos for sale on sites such as dsmtrader.com? I might be able to afford a used turbo if it is somewhere around $700 or so for a stage 1.

have you done a compression test? Thats one way to check how healthy your engine is. for all you know your headgasket is ready to go or something.

anyway I got 10.5:1 and am running a star turbo kit so yes you can use a turbo with that kind of compression. It spools faster too :) If you want a lotta turbo power then just go with 8.8 it'll be easier to tune well safer anyway.

rebuilding isn't always your only only choice you could always buy a used engine from an engine warehouse.

Why is hi comp better for nitrous, while low comp is better for a turbo? i dont get that... can anyone explain why? or is that just hear/say? thanks

bolt ons give a decent amount of power, and if you think its a waste of money to buy them new, search the for sale section here, ive bought almost every bolt on i have there.

Greddy Header, 100 shipped
afx 55mm tb, 90 shipped
afx UDP brand new with belts, 100 shipped
aem cai, 13 bucks plus shipping and a trade
strut bars, 25 shipped
GST catback, 65 bucks

Its very easy to find what you need, you just need to do a little searching.

Originally posted by GSGoinFast
Why is hi comp better for nitrous, while low comp is better for a turbo? i dont get that... can anyone explain why? or is that just hear/say? thanks

It's not that either of those saying are even true, as they are merely personal opinions. By "better" does the person saying such a thing mean it's better because it makes the most power? Or makes power the safest? Or maybe just makes it less work for them?

It's been said around here many times and I just make sure to mention this because its one of those preconceptions that always comes up and always bugs me. Here's some insight for you on these guys...

Hi-comp is better for nitrous?
Could be because the Nitrous not only adds oxygen to the a/f mixture, but also chills it considerably and yields a denser charge. If you raise CR, the temps will be generally higher, but the nitrous helps to lower the temps when you use it. Not so much as a cooling modification, but just when it's used.

Low-comp is better for turbo?
Low comp allows you to run more boost before you start to detonate. The higher the compression, the closer you are to compressing the a/f mixture to the point of it exploding prematurely (pressure makes heat - just like why turbos usually want an intercooler). So if you lower your CR, you essentially back away from the edge of detonation. Personally, I see it as being the lazy man's way of tuning, but to each his own, right?

Originally posted by DR1665 Low-comp is better for turbo? Low comp allows you to run more boost before you start to detonate. The higher the compression, the closer you are to compressing the a/f mixture to the point of it exploding prematurely (pressure makes heat - just like why turbos usually want an intercooler). So if you lower your CR, you essentially back away from the edge of detonation. Personally, I see it as being the lazy man's way of tuning, but to each his own, right?

Another thing to think about with that though is this. Whether with higher compression and low boost, or low compression and high boost, you're shooting for an actualy cylinder pressure which produces power. When air is compressed, it heats. So when air is compressed in the cylinder due to high compression, there is no way to remove the heat. When air is compressed through a turbocharger or supercharger you can use and intercooler/aftercooler to reduce temps while still maintaining pressure. There was a pretty good discussion about this going on se.dsm, but some Honda troll got on there and screwed it all up.

i have stock compression je pistons.....i think they were custom made though...330$ from ebay!
doug