Big Bird WS6

iTrader: (9)

what will 1 compression point make for horse?

like if i have 9:1 and i went to 10:1 or backwards. what will that charge.

i no i can run more boost with the 9. but level boost out. except for there being boost

18psi on 9:1
compared to
18psi on 10:1

thanks

Big Bird WS6

iTrader: (9)

anyone with a ruff answer. like 2%, 5 % anything. nothing?

come on. someone knows

Big Bird WS6

iTrader: (9)

so all these boosted nuts. and no one can even say there opinion. lol come on guys

ls1greg

iTrader: (2)

http://www.musclemustangfastfords.co...tio/index.html

Two Ford 4.6L engines tested N/A and with a Kenne Bell, one at 8.1:1 and the other at 10.1:1. It's not exactly what you're looking for since the boost isn't exactly the same, but it's close.

The number I came up with is ½% for 1 point in compression, but don't hold me to it!

BadgeZ28

iTrader: (28)

boost tends to equalize that difference. The big concern is the added chance of detonation with the higher ratio. A bit more advance can be applied with the lower ratio as well. Why increase the chance of damage for a few more hp?

Big Bird WS6

iTrader: (9)

so if i am running 100 octane(e85) should i stick with 10. or is 9 better.

MY99TAWS6

iTrader: (3)

More compression give more power but boost can make more power than compression increases. Still more powerful an engine is to start with then just means turbos will max out at lower boost and should have more area under the curve? .So 10 to 1 might give 800rwhp at 15 while 8. 1 might need 20 to do it. Engine cubic inch does pretty much same thing. As do better flowing heads and cam and all that .Just let you hit your peak potential at lower boost levels. And remember you are not always in boost. So more power off can't hurt either especially in a street car that spends most of its time off boost. Trust me you won't be in boost much in daily driving or you will be in Jail!

guys generally like the higher compression for other reasons..offboost and there is some debate if higher spools up the turbos faster.

I usually here 8.5 or so for track, 9.0 as nice ratio for no alc injection and 9.5 like mine if you are going to run alc injection which I am.
e85 could easily run 10 to 1 but e85 is not everywhere at least not where I live.if fact its nowhere up here..4 pumps in the whole country.

So might be a reason to go down a bit to 9.5 maybe.

I think my 91 talon is 7.5 but my 97 is 8.8 with the pistons I put in .Some guys go 9 to 1 and again on alc injection still run high boost . I think its more like 5 per cent per half point.

On the afr website there are a couple of thousand hp twin turbo builds. At least one of them runs like 9.5 I think it was. They also ran fast intakes..the one had sheetmetal but then said think fast gave better powerband.
You can find them under mag articles on the site.

Denali08

Something missing for the comparison is, what fuel?

It will be hard to run 18 psi with 10:1.

Assuming you run race gas or e85, 10:1 will net more power.

Big Bird WS6

iTrader: (9)

ok reason i am asking. motor isnt together yet. but i just reliesed that i was sold the wrong pistons. the ones i wanted should of put me at just about 9.8 to 1 and i the ones i was sold puts me at 8.9 to one.

and i already have all this **** balanced. is it worth switching?

BoostnTBSS

iTrader: (-1)

I run e85 and about 10.5-1 with my setup and it helps alot for making boost. i could see 10 psi at 3300 with the 346 ci and a S88 with 1.32 ex and it was rising like a rocket but dyno could not hold the load so more testing to come.