KB on all forged internals

stanger20

New Member
Mar 12, 2004
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I'm in the process of doing the 9 psi KB with all opitions in 5.0 mag they got 410-430 rwhp. I'm putting it on a new all forged block with factory pI heads . Any ideas what my rwhp would look like. Its going through a built t-45. It's going into my 96 Gt. also any idea of what track times 1/4 would be with 4.10 gear and slicks or 3.73 with this option. Should I go with the Kb or 150 wet shot :shrug: undefinedNX any input greatly appreciated I think I should run at least high 11's. my main concern is to keep it very dependable thats why i going to go with the all forged block just to be safe.
 
What compression are you going to run with? With the stock heads, you probably wont see more than like 450-470rwhp. There is more involved than just using race gas and cranking up the boost.

I would get the KB.
 
Get the motor built with the lowest compression you can. KB suggests 8:1 .
You will easily see 11's. I did a 12.3 @ 114 in Phoenix my first time out. I was completely stock other than the KB and Nitto's. Even with the stock 3.27 gears and everything else I think I could get into the 11's my next time out.
 
B C said:
Get the motor built with the lowest compression you can. KB suggests 8:1 .
You will easily see 11's. I did a 12.3 @ 114 in Phoenix my first time out. I was completely stock other than the KB and Nitto's. Even with the stock 3.27 gears and everything else I think I could get into the 11's my next time out.

actually if you want to build a motor correcty. That low of CR sucks. The reason people put low compression into cars is for running with lower octane fuel. You would actually want your CR to be around 9:1 and some even want it at 9.5:1. Just adding most boost to a motor doesnt equal more power. Lower compression, lower octane fuel and more boost means less timing. All that together means less power.

I plan on running 9:1 with forged internals. I could go higher because I have 94 octane fuel available to me but that will be a decision I will have to make.
 
B C said:
Get the motor built with the lowest compression you can. KB suggests 8:1 .
You will easily see 11's. I did a 12.3 @ 114 in Phoenix my first time out. I was completely stock other than the KB and Nitto's. Even with the stock 3.27 gears and everything else I think I could get into the 11's my next time out.
Hey BC, was that run on street tires?
 
mogs01gt said:
actually if you want to build a motor correcty. That low of CR sucks. The reason people put low compression into cars is for running with lower octane fuel. You would actually want your CR to be around 9:1 and some even want it at 9.5:1. Just adding most boost to a motor doesnt equal more power. Lower compression, lower octane fuel and more boost means less timing. All that together means less power.

I plan on running 9:1 with forged internals. I could go higher because I have 94 octane fuel available to me but that will be a decision I will have to make.

I'm afraid not... Within reason the lower the compression the more boost you will be able to put through the KB. I think on pump gas it is possible to get 20 psi out of the 1.7L KB if you were to go with an 8.0:1 compression. I wonder why ford chose 8.4:1 for the roots style blower on the 03 cobra...maybe because lower compression allows for safer high psi boost level. You will lose some power going with lower compression but as long as you stay in the 8's range you'll WAYYYY outway that power loss with gains from higher boost. Lower compression is the only way to get high boost on pump gas. Other wise your engine will go *boom*.

kirkyg
 
kirkyg said:
I'm afraid not... Within reason the lower the compression the more boost you will be able to put through the KB. I think on pump gas it is possible to get 20 psi out of the 1.7L KB if you were to go with an 8.0:1 compression. I wonder why ford chose 8.4:1 for the roots style blower on the 03 cobra...maybe because lower compression allows for safer high psi boost level. You will lose some power going with lower compression but as long as you stay in the 8's range you'll WAYYYY outway that power loss with gains from higher boost. Lower compression is the only way to get high boost on pump gas. Other wise your engine will go *boom*.

kirkyg

DO you really want me to start quoting documented books? Cause I have a few sitting in front of me.
They put lower compression into a stock forced induced motor for the mere fact that you cant always get 92, 91 or higher octane. It has nothing to do with the amount of boost said Blower can produce. If some yahoo in a 03 cobra accidently put 87 octane in or the said gas station runs out of 91 or whatever. The lower compression will allow the motor not to grenade itself.

let me guess, you would rather run 20psi with 8cr with a crap load of timing pulled than 15psi with 9cr with more timing?