Outer Limits 4x4 Board

hey all, i have put a t3 t4 turbo on me 4.2. running gas research and intercooler. got the pertronix elec ign, with flame thrower coil. k&n Apollo air filter hooked up to the snorkle.

now it has been dyno tuned and it still flat spots every now and then and breaks down after about 3500 4500. it still pings when i give it a boot full. i was told to take my dizzy to the auto elec and get the timing sorted out. is there any info i can get to find out if the timing in the dizzy is gonna fix the breaking down and flat spots or is it something else??

Give Joel a call at PGS in Mornington.

Wow! that is really bad if it has been dyno tuned

X 2 Joel and the boys at PGS know there stuff. really good with GR tunning

PGS (03) 5975 2642

valve springs mate, they could be bouncing and holding open

i wouldn't be boosting it at all if it's pinging. fix the timing and it won't blow up at least

Hey Daniel Son you need to run your snorkel into the cab!!! that will fix all your pinging probs.
Failing that, pinstriping is a known cure for pinging as the first three letters are the same.

Glad I could help dude.

bagsy wrote:http://www.biders4wd.com/

x2 did a good job on ours

cool, thanks will give em a call and see how i go..

not revving could be due to the lack of spark! when i turboed mine i put a msd on it to get the extra spark otherwise its like it had an inbuilt rev limiter.

sounds like u got a good dyno tune!! did they tune or just dyno and see what numbers it made or how pretty the wheels looking spinning on the rollers?

The petronix output isn't sufficient for turbo applications, I't may be better with the flame thrower coil but haven't tried it. I use the petronix to drive an ICE module for any reasonable boost application.
The distributor will need regraphing, it is something I normally do in house as the requirements are pretty simple in this application. Without having it on the dyno it is hard to see exactly what is wrong but I can give a number of reasons for pinging, poor driveability, low power and breaking down.

Insufficient LPG flow.. one converter and and line is good to about 160 rwkW
Excessive mechanical advance.. certainly a problem.
Possible needs valve springs..will cause low power at high rpm but not pinging.
Poor tune..set too lean or rich..not many people tune Gasresearch correctly.
Breaking down at RPM, insufficient spark..spark being "blown out by cylinder pressure.

Cheers

Joel

PGS 4WD wrote:The petronix output isn't sufficient for turbo applications, I't may be better with the flame thrower coil but haven't tried it. I use the petronix to drive an ICE module for any reasonable boost application.
The distributor will need regraphing, it is something I normally do in house as the requirements are pretty simple in this application. Without having it on the dyno it is hard to see exactly what is wrong but I can give a number of reasons for pinging, poor driveability, low power and breaking down.

Insufficient LPG flow.. one converter and and line is good to about 160 rwkW
Excessive mechanical advance.. certainly a problem.
Possible needs valve springs..will cause low power at high rpm but not pinging.
Poor tune..set too lean or rich..not many people tune Gasresearch correctly.
Breaking down at RPM, insufficient spark..spark being "blown out by cylinder pressure.

Cheers

Joel

Sorry to hijack but i am about to go this same route, replacing the TD42 with a rebuilt TB42E that will run straight gas using a Gas Research Throttle body on the EFI prelium chamber. Going to use the TB42S carby for the ignition. Would the Crane Cam Fireball XR700 be ok to use? would the dizzy need to be modified? if so what needs to be done to make it turbo compatible?

There are 2 crane units one more powerful than the other. The XR 700 is a points replacement for low igntion output (not turbo) the crane XR 3000 is the high output version that you need. The ICE module is every bit as good (better going by the results at the USA engine masters competion) and Australian made, it can be triggered off points but I rather use a petronix igniter as the trigger.
You generally don't need a boost retard up to 15 psi, just a locked distributor with vac advance for cruise timing. I would have to say I have set up over 20 Patrols like this and countless more Gas Resaerch Falcons without a problem, you will get improved economy and part throttle response, lastly I set it up for mixture on the dyno and power time the distributor for peak power without detonation. It's not computer controlled with air temperature and engine temperature compensations so it's best to be a little conservative with the timing.

Cheers

Joel

thanks guys all good info,

what tests can i do to check if its the valve springs?,
and it does feel like as soon as it gets to 9 to 10 psi boost it just breaks down like internal rev limiter so the pertronix could be an issue..

will i have to upgrade the spark to stop it from blowing away??
my spark gap is set at .8..

the auto elec is going to re graph the dizzy but not much point if i have to change the petronix..

as for the dyno i was told the gas flow was fine throughout the dyno run so don't think the gas is the prob..

thanks Dan

Drop the gap to 0.6mm or less first.

Definately dont want 0.8mm with turbo and LPG. Leads will break down unless they are top quality.

I am running 0.5mm gap.

Closing the gap is OK, to a point, on LPG as plugs don't foul ,generally the problems are minimal but if you are at .5mm on petrol you would be likely to experience missfire and poor idle quality at low speeds and cruise, little plug gaps also mean leaner cruise mixtures can't be run as with low turbulace a poor flame curnel propagates (poor economy). There is a reason late model cars run large plug gaps. If you go below .7mm of plug gap you should be upgrading the ignition, you will make more power if you do.

Cheers

Joel

Yeah i agree Joel. Large gaps are only a benefit to lean mixture ignitability.

This comes from NGK sparkplugs own technical manual.


"Modified engines with higher compression or forced induction will typically require smaller electrode gap settings (to ensure ignitability in these denser air/fuel mixtures) as the voltage requirement at the electrode gap is increased due to higher combustion pressures. As a rule, the more power you are making, the smaller the gap you will need. "




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