Thread: Went to the dyno today

The FS4 certainly have a crazy sound, that's why I got the number plate 2RETTS! Even the Kelfords don't match it... I will probably go back to my FS4 as one of the final things I do with the VE as they have better power under the curve.

And I'm in agreement with Rob, we did the calculations & measured the valve to port opening too & 7" is the ideal length port-face to bellmouth opening for peak power at 8,000rpm.

Calculation for intake runner length power: 97,000 divided by Peak HP RPM = X inches from back of valve to plenum (or bellmouth) opening.

Calculation for intake runner length torque: 108,000 divided by Peak HP RPM = X inches from back of valve to plenum (or bellmouth) opening.

It's 13cm or about 5.12 inches from the back of the valve to the port-face.

Been reading up a bit on the theories of intake manifolds etc. Most of it is based on intakes with a plenum on it.

Clint I'm curious, when you guys did the calculations, were you using the formulae for normal (plenum'd) runners?

The reason I ask is because ITB's don't have a plenum that can bounce back the pressure waves and therefore I suspect the theory would not hold for itb's. I could be wrong but this seems to be one of the critical underlying assumptions in all the calculations/calculators I've come accross.

Also, I can't seem to find anything on the positioning of the butterfly in relation to the back of the valve? Anyone has info on this?

Went back to the dyno today. Some more tuning was done as the car was extremely rich after the initial tune.

The new numbers made me feel a bit better. Need some more work around the switchover point but it's getting there.

again, bear in mind 17% loss due to altitude.

So lets see you are making 202 WHP and with 16% more WHP at sea level would be


234 WHP.

It's at the wheels AM.

What is the complete parts list again?

+FS4 valvetrain, 370cc injectors, pulleys, knife edge crank, some headwork. This run done back on the stock IM while we're busy with some changes to the intake setup.

So the stock IM made the 234 WHP numbers.

FS4 cams
Valve springs and retainers
Ported Head
SR16VE Pistons making ( 13.5 to 1 compression )
4 into 1 header
370cc injs
Knife edged crank
Pulleys


I am a big fan of intake manifolds and feel a IM with a large 80-100 MM TB will outperform the ITBs

Great job.

Yeah I was surprised too. I must mention that it was quite cool today compared to the previous day I was on the dyno, and I'm not sure if they compensate properly for that. But be that as it may, I am still pleased at how the car feels now.

I'm weary to write off the itb's though. When I removed them I noticed that they weren't sealed properly with silicone where the ITB meets the adaptor plate, and I think that affected them somehow too.

But the main problem seemed to be that the tuning done previously (by a different tuner) was way way way too rich. AFR's in the 12s. When the cams switched you could see think clouds of smoke come out the exhaust.

Pistons are shaved and pocketed. I think static CR is close to 13:1 give or take. And the run was on 95 RON fuel.

in the dyno comparison, what cams were in it originally?
Or is that vs untuned.

I'm with miko, intakes are the next thing to be unlocked for more power. So close to being able to afford mine to be built.