[Guest]

Short story: Have bitten the b

Short story: Have bitten the bullet to port the 3.2 head. Peak flows using a larger intake valve are now up about 20% over stock, with even more area increase under the intake curve due to increases in volume transferred and velocity across the cam profile. The numbers we are getting are very sinilar to and bear out former poster Kermit's data on his qv head flows. Am also looking to take advantage of the better flowing head with a much larger lift cam, about .400

The flow bench has now identified the current 40DCNFs as the new flow restriction, so after re-calculating requirements a set of 44DCNFshave been purchased to replace them.

A set of Euro-spec tubi headers are being ceramic coated in and out to help aid exhaust flow.

So now, I have to decide if it is cost value addd to complete the project with 10:1 pistons. I will be using street gas and the extra flow already means my cylinder pressures will be higher, so I am leery of detonation on street gas.

Attached first below is one rear wheel horsepower computer projection with the real world current dyno, where the hp continues to build as the engine now does not run out of air. Attached second is an overlaid second computer projection that give the same peak, but also have more hp and torque coming in much lower in the rpm band. Remember this is rear wheel hp after about a 17% driveline loss.

Not sure of what the final will be, but I am hopeful.

All experience and advice welcome.

 

[Guest]

If you go to the 10:1 pistons,

If you go to the 10:1 pistons, make sure that you deburr all surfaces of the piston and really polish all area's on the top of the piston, same thing for the combustion chamber and squish area. No sharp edges that will allow hot spots to form. Even JE pistons as good as they are, require at least 1 hour of detail work per piston. This will help delay detonation. With some current 4 valve heads with swirl chambers we can run 12.5:1 on pump gas.

 

[Guest]

Thanks for the words!
What do

Thanks for the words!
What do you or others think would be a good compression? - I've talked to Norwood and Carobu and they said on street premium I could get away with 10.5, or maybe 11:1.
I am currently settling in on 10.5:1 a bit as it does use carbs and does not have a knock sensor or any high tech gizmos - this is a very simple engine compared to newer models.

 

[Guest]

If you go too high, you will n

If you go too high, you will need to take spark advance out,(as you know)and that will reduce the horsepower. Double edge sword. From what Norwood told you, I would not go over the 10.5 deal for the street. That would be safer for that bad tank of street gas that you will buy sometime. It all depends on how fast your combustion chambers are and the flame path. you can change some of this with welding and grinding and alot of dyno work. not worth the effort for street use. Stay with your plan and if you want more easy power, give it a wet NOS system. + 50, 100, 150 horsepower and normal for just driving. I know that "ferrari people" don't hot rod Ferrari's, but what sleeper you would have.
just my random thoughts and worth every penny you paid for them

 

[Guest]

Well, have decided on 10.5:1.

Well, have decided on 10.5:1. It's over a point higher than the stock 9.2. I am really hoping for some low end umph from all this. I pretty hopeful based ofn some discussions (well, I wasn't sayng anything) with Frank Capo in Australia. He feels these "motors with comp are good for #$%^#$ 350 - 360 hp all day no sweat, mate".

 

[Guest]

LOL!

I think 10.5 is a safe

LOL!

I think 10.5 is a safe bet given ongoing fuel reformulation..

So you went with Tubi headers finally?

That's one mod I am anxious to do on all three cars, I have had OEM ones 'wear out' and it's quite dramatic....

 

[Guest]

yes - I went with the tubi hea

yes - I went with the tubi headers - they are being ceramic coated in and out. The head flow numbers may not be as great as expected, so I'm hopeful for a hp # over 320, which would still be great. I am consciously choosing to keep low end instead of the most wompus top hp number.

I am struggling a bit with the ignition - whether to keep the Unilite/MSD or try an electronically controlled advance distributor.

Although it may not seem like much to many folks, I am also focused on velocity stack and airbox design. I am hopeful that the new single design will be a good combination of low flow resistance, high velocity and effective filtering and weather functioning.

 

[Guest]

yes - I went with the tubi hea

yes - I went with the tubi headers - they are being ceramic coated in and out. The head flow numbers may not be as great as expected, so I'm hopeful for a hp # over 320, which would still be great. I am consciously choosing to keep low end instead of the most wompus top hp number.

I am struggling a bit with the ignition - whether to keep the Unilite/MSD or try an electronically controlled advance distributor.

Although it may not seem like much to many folks, I am also focused on velocity stack and airbox design. I am hopeful that the new single design will be a good combination of low flow resistance, high velocity and effective filtering and weather functioning.