Detonation Problems !!!

Mussey38 · Dec 12, 2014

Hi !

My first post and im over in sunny UK !lol Have a 96 GT which I have just finished a PI headswap on to NPI original Block.
Spec-
-99 windsor heads with light gas flow
-stage 1 comp cams
-pro comp aluminum intake /same as typhoon
-70-75mm throttle body
-summit 85mm maf
-24Lld injectors
-msd coil packs with ford racing leads
-NGK iridium plugs
-bbk fenderwell cold air
-Fluidyn alloy rad and 180deg thermostat with Evans waterless coolant !
-Egr still working
-stock PI headers
-pypes hi flow cats front sensors in place
-bbk H pipe into magnaflow cat back
-SCT tuner with brenspeed custom 93 tune
-Run it on Shell optimax 98 octane fuel

The car was a Jap import and is a mint car .Just over 45,000 on the clock. The car is going very well now apart from the Detonation when under load .Have retarded the spark timing on tuner with no result.The tune was written for the car with out the head swap so im thinking its the tune maybe.Have data loged it with realtime genesis reader so can see everthing is running fine and working .

Need help Please !

Ask away

Paul

D3VST8R96GT · Dec 12, 2014

Do you have a fuel pressure gauge? That and a wideband are the first things I would want... detonation on a 93 tune with 98.... hmmm

yzfr6i · Dec 12, 2014

Doesn't the PI head swap up your compression? If the tune was written for stock heads with lower compression that could be the cause.

96blak54 · Dec 12, 2014

How do you know its detanation? What rpm does "detanation" occur? If it truly is detanation, its because your maf is dirty, pegging out earlier or you got ahold of crap gas or possible mail order tune is junk. Un-mettered incoming air such as gasket leaks will lean out also. The only way detanation will be relevant is through leaning out. Your compression is no where near the point of detanation even without a tune with 93 octane let alone 98.

kb1982 · Dec 12, 2014

He is across the pond where they use a different formula to determine octane rating. Their 98 is about the equivalent of our 93. They only use the RON where in the us, the formula is (R+M)/2 which means a combination of road octane number and the motor octane number. Other than that, I have nothing useful to contribute.

96blak54 · Dec 13, 2014

Your contribution is well accepted ...thank you!

D3VST8R96GT · Dec 13, 2014

Metric octane .....

Mussey38 · Dec 14, 2014

I am going to put standard maf back on and change in sct tuner and try that .If no luck will put 19Lld injectors back in .Any recomendations as to good companys for tunes for the sct ?

96blak54 · Dec 14, 2014

Your situation needs to be dyno tuned. Are there any sct tuners available in the UK?

D3VST8R96GT · Dec 14, 2014

JJ at wms (woodbine motorsports) he can email tune pretty damn good. Well known in the lightning crowd with multiple email tunes in the 10s

Mussey38 · Dec 14, 2014

Plenty of dyno's but no one that know anything about sct tuners. have spoken to local dyno and can put on to see what it is doing.can play with the sct tuner while there my self .