8:1 vs 9:1 in the SVO

[mallethead]

All,
I was wondering what difference in power an 8:1 compression SVO would yield vs a 9:1? I know the turbos love the lower compression, but what would be the difference in Power, if any? Would it hurt the turbo or valves? The reason for the question is my engine rebuild. The engine builder was going to use 9:1 pistons with a different cut, but is now going with the proper Speedpro pistions. He claimed there would be less turbo lag with a 9:1 compression ratio, but I kinda find that hard to believe. Any thoughts?

[PsRumors]

On my Trailblazer I was running 11:1 compression and 9lbs of boost making about 480 rwhp with a supercharger. But the most timing I could get into it was 18 degrees on 93 octane. I know it is a completely different setup but it does go to show you the more compression the less boost and timing you can get. Timing under boost is power.

You would probably feel less laggy depending on the turbo your running but I don't think it would be significant, 300 rpm or less. These motors love boost and make their power under boost. If you could get 250 hp out of the motor (off boost) by upping the compression ratio by 1 point I would say go for it but I doubt you will. You need to be able to stuff as much air in with as much timing as possible which lower comrpression will allow you to do.

Stay with the 8:1, it's proven, it works. Unless of course you are going to run e-85.

[SVOeric]

both good answers there...

the short version, if you don't want to buy a eec tuner, or stand-alone computer, and totally re-tune the engine, you need the RIGHT pistons & 8:1 compression.

9:1 with stock computer will get you detonation, until you retard the timing a ton, which will yeild less performance in the end.

[hotrodfeguy]

I was planing on 7.0: 1 on my next build so i could run more boost/turbo myself.

[mallethead]

All,
Thanks for the responses and the education! I appreciate your knowledge more than you will ever know. I am currently not looking for increased HP gains, just stock numbers on the 4e. I plan on buying a 1c in the future and going at it whole hog! The 4e is more for show & shines, reunions, etc. I truly believe that in 8 or 9 years this car is gonna be worth a lot of money. Correct me if I am wrong, but it seems to take about 30 years before collectable Mustangs shoot up in price/worth. I appreciate all your help and look forward to your insights when the interior is started!

[SVOeric]

I truly believe that in 8 or 9 years this car is gonna be worth a lot of money. Correct me if I am wrong, but it seems to take about 30 years before collectable Mustangs shoot up in price/worth. I appreciate all your help and look forward to your insights when the interior is started!

I wouldn't hold my breath.... The people that are in the SVO market for investment, or think they are going to make money generally don't stay long.

[mallethead]

I wouldn't hold my breath.... The people that are in the SVO market for investment, or think they are going to make money generally don't stay long.

I understand what your saying Eric. I really love the SVO and could just kick myself for getting rid of my first one, which was an 85 grey. It didnt take me long to start looking again and I feel truly blessed to have found a 4e that was for sale. I didnt think I would ever see one. One of the members avatar says its a sickness..I'm beginning to believe he's right!

[hotrodfeguy]

But there is a cure !!!! LOL

[84svslow]

a 93 cobra r one of the lawsuit car sold for 80k it had 83 miles on it