im about to rebuild the good ol 7m and was wondering if it would be a good idea to bump the compression to say 9 to 1 with forged internals because from what i hear it helps make better power and spool the turbo quicker with higher compression. any thoughts?
7mgte raising compression questions?
- Thread starter solpower
- Start date
No....not going to explain why as it's so basic that you can research it yourself..
All I'll say is it's stupid to increase compression on a turbo car.
All I'll say is it's stupid to increase compression on a turbo car.
MRSUPRA;1250392 said:
Man plays Russian rulett (sp) and lives...
Does that mean playing Russian rulett is a good idea?
It can be done sure...will it increase bottom end performance? Yeah a tad.....is it worth the overall problems associated with higher compression? No.
I suspect that it depends on your goals, as usual. If you want stock power levels with better turbo response, then, well... maybe.
If you want more power, like most, there are better ways.
If you want more power, like most, there are better ways.
I'll enjoy it while it lasts:naughty::biglaugh:
But agree reliable power/dd/big power....prolly not the best idea.
But agree reliable power/dd/big power....prolly not the best idea.
Hey guys. Look at most aftermarket forget pistons specs. They're _rising_ CR. The only pistons _lowering_ CR a bit I've seen are probes.
PS: Gabon, don't tell me about russian rulette, please
I deal with it every moment cause I'm in Ru.
PS: Gabon, don't tell me about russian rulette, please
I deal with it every moment cause I'm in Ru.It's not that big of a deal you will get more off boost power as my car feels like the average 6cyl then the boost hits. I means more power to drive the car with out boost and a bit better spool. What will make the big diffrence is how the car is tuned. Bumping it up to 9:1 means you have less of a margin for error in the tune. To date i put in 12k on a vpc afc and t-70 hard miles. With my new setup (same pistons) stand alone ecu i run 18-20psi on pump and have put on 15k hard miles from day one. Again it's in the tune
"Man plays Russian rulett (sp) and lives.."
What are you talking about?????? I'm tuned with an AEM. Can you say "timing control". I don't care what compression you run, with the stock ECU and the crazy high timing you get, you are at more risk for knock no matter what.
GO ahead and run 7.5 to 1 compression and see how your supra will feel like it has a 1.6liter in it.
What are you talking about?????? I'm tuned with an AEM. Can you say "timing control". I don't care what compression you run, with the stock ECU and the crazy high timing you get, you are at more risk for knock no matter what.
GO ahead and run 7.5 to 1 compression and see how your supra will feel like it has a 1.6liter in it.
im just saying i want a little more out of boost power and i dont have plans of going past 15 or 16 psi and im only shooting for about 350 or so hp i just want a decently strong dd but i hvae to rebuild it anyway so i figured id help out the bottom a little
Raising 0.5 CR isn't really worth the hassle especially on a 3L motor, for example on my v8(5L) i raised my CR from 8.5:1 to 9.5:1 when i fitted a higher lift/longer duration cam (given it was n/a) it only was worth 7rwkw
if anything you'll have to pull more timing on boost to avoid pre-ignition/detonation, sure you'll have a marginal increase off boost but you'll loose power from where it counts.
if anything you'll have to pull more timing on boost to avoid pre-ignition/detonation, sure you'll have a marginal increase off boost but you'll loose power from where it counts.
Another good post 2 ducks!
I tend to go the other way on Turbo motors and drop the comp a little to give a little more overhead in case of detonation as 1 bad rattle WILL ruin your entire day.
Any loss of power is more than made up for when you add boost, my motor has brilliant off boost response/drivability but as mentioned in the thread this is more due to the tune.
8.26:1 last time I measured it all but probably closer to 8.3:1 after the last build, my old 4v V8 by comparison was 6.5:1 and still drove nicely off boost.
I tend to go the other way on Turbo motors and drop the comp a little to give a little more overhead in case of detonation as 1 bad rattle WILL ruin your entire day.
Any loss of power is more than made up for when you add boost, my motor has brilliant off boost response/drivability but as mentioned in the thread this is more due to the tune.
8.26:1 last time I measured it all but probably closer to 8.3:1 after the last build, my old 4v V8 by comparison was 6.5:1 and still drove nicely off boost.
also should i go for a bigger turbo because im bored with the ct26. this is the first supra so im just trying to get some advice from yall
solpower;1252105 said:
The lower the compression the more boost you can run. Turbo cars are meant to have low compression. My friend with an sr20det bumped the compression up to get a better spool and what not and he ended up blowing the motor.
Turbo cars are meant to have lower compression, not low compression. Rarely do you see newer turbo cars running lower that 9.0 compression. Cars that had 7.5-8.5:1 compression ratios are mainly from the 80's where lack of knock control and unsophisticated engine management where the norm. Cars are now made to not feel lik a slug before the turbo kicks in; Like my 91 Eclipse GS turbo which had a 7.8:1 compression.