deacs

Can anyone help??

Im running a United Kingdom spec civic D16Z6 with T3 turbo at 0.5bar, 450cc dsm injectors and a 220lph intank, static timing retarded 4 degrees, S-AFC set to -25% at idle then -35% all the way up to 8K.

Problem I have is when at WOT i get some audible detonation!! UK pump gas is 95 RON so its in general higher octane than u guys have but for some reason im getting detonation??? can u suggest why??? is it my plugs???

I wanna get up to 10psi which i should be able to with this set up but im not sure whats going on, my autometer A/F gauge reads Rich ( bout 3 green LEDS) at WOT but still detonation!!

whats going on?? suggestions???

Paul

UK Civic turbo

rioninja

Check all your lines, is possible you have a boost leak. If so, your turbo is going to spin a hell of a lot faster to keep the pressure up, which means its gonna blow pretty hot air.

Quiz

If you are using stock plugs you may want to try a range or two cooler plug. Look for deterioration on your current plugs.

BudaKai

If it's only doing it at the higher rpms it means your leaning out a bit. A boost leak would cause it to see dotonation when ever it saw the said boost level. Turbos do lose efficiency up there but he said it was in the higher rpms not the higher gears that would cause the greater amounts of heat. either increase your flow rate or shift sooner that all you can do really Those boxes help with the added fuel flow but under boost I wouldn't trust one just my honest opinion that and I'm high.

rioninja

With 450cc injectors and the safc set to -35% your running very very rich. Even without the intank you would be rich as hell at -35%.
I have friends who have run 89 octane on the vafc hack without detonation.
It still sounds to me like a boost leak.
Also, are you sure the injectors are 450s?
Are you familiar with the sound of detonation? Is it possible that what your hearing is mis-firing?

glagola1

I don't know anything about the hack and 450's but I do know that the a/f meter showing 3 green lights is pretty lean. That's way leaner than a stock turbo car would run and don't forget the fact that the a/f meter only reads 14.5:1 clearly and anything above or below that is vey inaccurate so don't trust it.

I say get your *** to a dyno and do a couple runs with a wide band a/f meter. Once you get it running right forget about it. The only way to truely enjoy a boosted car is to tune it properly and forget about it. Hell, I almost went n/a because I was too cheap to get to a dyno.

They do have dyno's in the UK right? JK

deacs

so how does a boost leak cause detonation??? i dont understand???

My boost gauge reads a steady 0.44 bar under WOT.

deacs

deacs

can anyone explain why boost leak will cause detonation???

Also after a run my air inlet pipe (from the intercooler to the throttle body) feels slightly warm to touch, is this normal???? thats after driving on open road with a outside air temp of 18 to 20 degrees C.

thanks

paul

rioninja

If you wastegate is set to .5bar for example, and you have a boost leak.
The turbo will have to spin much much faster than normal to make the same boost. An overworked turbo will be way out of its efficiancy range, and the air pressure produced will be extremely hot.

Quiz

If he has the wastegate supplied at the manifold a boost leak will cause the turbo to work harder to create 7psi. A less dense (hotter) intake charge, especially on a car without an I/C is more likely to detonate. If he has the wastegate supplied at the compressor outlet it will still show the wastegate 7psi and the turbo will not be over worked but a boost leak will not show 7psi at the manifold. If you had a MAF then there would be a rich condition due to a loss of metered air. Since you have a MAP you should not have a fuel issue but rather an intake temp issue. Someone stated they thought this car is leaning out. I would take his suggestion of dynoing with a wide band A/F meter and also look for a pressure loss.