Failed piston ring?
- Thread starter Kooldino
- Start date
I was giving a rough estimate... but yes I agree... I do lean slightly more toward the higher compression though for more daily driven vehicles etc, and for low end torque if you are using a bigger turbo that is more laggy. 'Cause peak power isn't the whole story as we all know.MPNick said:
I can understand the thinking but I do not agree with it. I do see alot of people feel the same way about thinking they will get more lowend with higher compression. I do not see this to be true in the modern turbo.TurfBurn said:
How much power would a 9 to1 Mazda make? Both peak torque and peak HP. Even look at the start of the torque build. If you take the same given engine, lower the compression to 8 and run more boost with the same turbo, I guarantee you that you will have more lowend torque and sooner.
Running lower boost means less power, plus you will have to run less timing with more compression.
You would know better than I. For me to hold my ground on the statement I would have to find a lot of dyno's etc. It was just a statement of my understanding of the compression issue as I have seen from general info from random places (which as you said, it is a view that has been expressed by many... accurate or not). The only analytical statement I think I could stand up for though is that if those compression points are the straw that breaks the camel's back as far as the turbo is concerned. Example being that if the T25 is/was supposedly peaked out at 16 psi and that was about where you were running... then lowering your compression would put you further past the efficient point of the turbo and you'd make less power.
Also, a tuner I had spoken with a month or so ago said that you'd yield better power leaning a car than advancing the timing... which I realize is one school of thought versus another... I personally prefer the opposite at this point as I rather the cooler combustion temps.
Although
If you want to put a GT60R on an 8:1 car versus on an 9:1 car I have a feeling that anything below 3 or 4K the 9:1 car will make more torque 
. (For those of you that don't know... the GT60R is a 141mm compressor versus the GT28R's 60mm compressor)
Also, a tuner I had spoken with a month or so ago said that you'd yield better power leaning a car than advancing the timing... which I realize is one school of thought versus another... I personally prefer the opposite at this point as I rather the cooler combustion temps.
Although
If you want to put a GT60R on an 8:1 car versus on an 9:1 car I have a feeling that anything below 3 or 4K the 9:1 car will make more torque . (For those of you that don't know... the GT60R is a 141mm compressor versus the GT28R's 60mm compressor)Very good points and I see where you are coming from.TurfBurn said:You would know better than I. For me to hold my ground on the statement I would have to find a lot of dyno's etc. It was just a statement of my understanding of the compression issue as I have seen from general info from random places (which as you said, it is a view that has been expressed by many... accurate or not). The only analytical statement I think I could stand up for though is that if those compression points are the straw that breaks the camel's back as far as the turbo is concerned. Example being that if the T25 is/was supposedly peaked out at 16 psi and that was about where you were running... then lowering your compression would put you further past the efficient point of the turbo and you'd make less power.
Also, a tuner I had spoken with a month or so ago said that you'd yield better power leaning a car than advancing the timing... which I realize is one school of thought versus another... I personally prefer the opposite at this point as I rather the cooler combustion temps.
Although
If we stay with a spec engine, I do not care what kind. The main thing is it must stay the same, turbo, intercooler, exhaust and all other things. Build, tune and dyno test the 8 to 1 at 16psi. We are talking the GT25 turbo here.
Then replace the pistons with a set of 9 to 1. Tune and dyno test this setup. The turbo would be working the same in both engines, the rpms would be the same, the air temps would be the same and the flow would be the same. Both engine would produce peak torque at the same rpms. What would not be the same is the timing. The 8 to 1 engine could run more timing so the engine would rev faster. More timing would be lower exhaust temps. Lower exhaust temps would also mean less heat soak back into the cylinder head. Less heat soak would also mean less detonation. You could also turn up the boost more on the 8 to 1 engine and this would also get more peak torque.
You get no free lunch when you run higher compression on a street car. With the higher compression you have higher cylinder pressure. You cannot run the same timing for both setups. You will have to ower the boost and keep the same timing or ran more timing retard.
As for the GT60R that is an all out race car, very big intercooler and race fuel. Also they would not even start to boost until 4,000 rpms in most cars.
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LOL, good thing you dont know me. I only LOOK nice and innocent, heheehehehe. Yea, Im definetly out there... lol(burnout)MPNick said:
In a week Ill be out there...in Dino's garage...putting his engine back together, and then, making his tires bold, because of his secret.
Jeezzz....
You cracked pistons....I melted mine (not completely but the spot is there)!!! Im doing a compression test today!
That piston of yours looks like had some pinging/detonation!! Maybe too much timing>?
Look for the second crack. Take the rings out and the ring land should fall out of the piston.
You cracked pistons....I melted mine (not completely but the spot is there)!!! Im doing a compression test today!
That piston of yours looks like had some pinging/detonation!! Maybe too much timing>?
Look for the second crack. Take the rings out and the ring land should fall out of the piston.
