ben_r1 wrote:
Thanks for all the advice from members
Edit: on a side note how do you go about testing the spark strength on a modern ecu controlled car l. And regarding an earlier question, my car has a small primary cat at the end of the manifold where as the other car doesn't. This is a 300 cell type I believe, approx 1/3rd the size of a normal cat.
Is there much gain to be had from a straight through exhaust with nos?
That must the culprit. That catalytic converter chokes the engine when on the gas.
I have a decatted racemanifold on my car and it`s a night and day difference on and off the gas.
See if your can get a decat pipe. B.T.W. What diameter exhaust do you have?
One other thing that can have an adverse effect is the ecu. These modernday ecu`s have all kind of safety measures to keep the engine from knocking itself to death. But they can be overacting.
On my car for instance there is an active knock control system retarding ignition, but not when the knock sensor detects pre ignition but when it thinks the engine will detonate under certain engine loadings or fuel quality limits.
The detonation sensor is also a very crude one. It doesn`t have filters, so it picks up frequencies everywhere; road irregularities, noise from my race manifold, short ram intake, sharper cams etc. It even shows engine knocks when I accelerate hard in 1st gear because of my strengthened engine mounts.
I can monitor all ignition settings and detonation via my Hondata flashpro management system and I found that I hardly had to retard ignition advance, even when on a 100 bhp nitrous shot. What I did was compensating by adjusting fueling and cam angles.
The stock ignition advance curves were pretty conservative and the ecu had an overzealous tendency to remove ignition advance when it felt like it.
Don`t know if your ecu is chipped but the engine may be removing quite a lot of ignition lead as soon as you turn the gas on. On these engines as soon as you remove ignition timing you tend to loose a large amount of torque. My engine does.
I understood that your F4R 830 engine has a rather high 11.5:1 compression. Perhaps it is possible to have the ecu remapped to make it better suited to nitrous use.