timming on turboed TB42

[stevejl]

Hi there

I have a turboed TB42 on straight lp gas having a bit of trouble with pinging I have a pertroinics electronic system switching a 7 amp ice ignition module and a ice coil. plugs are two stages cooler than standard. As soon as the boost gets over 11psi it starts to pinging. gas side I am running a impco l type converter and a impco 225 mixer. just seeing if you have any info on setup. should I run fixed timing if so were should I set it at 10 15 20 degrees or do I have to get the dizzy re graft or a boost retard module what is the best thing to do.Thanks Steve

[jessie928]

Hi there

I have a turboed TB42 on straight lp gas having a bit of trouble with pinging I have a pertroinics electronic system switching a 7 amp ice ignition module and a ice coil. plugs are two stages cooler than standard. As soon as the boost gets over 11psi it starts to pinging. gas side I am running a impco l type converter and a impco 225 mixer. just seeing if you have any info on setup. should I run fixed timing if so were should I set it at 10 15 20 degrees or do I have to get the dizzy re graft or a boost retard module what is the best thing to do.Thanks Steve

you need to retard timing at boost.

JEs

[stevejl]

I no you need less total timing on boost but how much and what is the different ways to do it eg. fixed timming ,regrafe dizzy, msd boost retard module. if fixed timing will work good it would be a lot cheaper or even re grafe the dizzy would cost alot less than the msd option.but if that is the only way to stop it pinging at 15psi that might have to be what i do.

[chpd80]

You are best off getting the dizzy regraphed, locking it for idle and offboost will make it ping bad and locking for boost is just as bad for idle and offboost driving.

I would contact someone like Joel from PGS who does this all the time, it really needs to be right or it will ping then o bang.

DONT boost it if it's pinging or you will be looking on ebay for a secondhand motor.

If your planning on 15psi you must be chasing some serious power and will probably run out of lpg very easily. One convertor is usually enough up to about 160rwkw. and you shouldnt need 15 psi to get to that.

There is soooooo much more into it than you think when you start as I found but well worth it in the end, just do it right and you will love it.

[turbmav]

Have you decompressed it using a thicker head gasket? sometimes the lose of Quench in the combustion chamber premotes pinging. I'm running 10 inital 27 total and the vac advance. No pinging here. Big front mount intercooler also the key.

[PGS 4WD]

There are a number of ways to rectify this, you can do it with boost retard modules of which there are a few, they do work OK if you lock the mechanical advance and retain the vac advance for cruise timing. It should go on the dyno to set it for peak power (without ping) but once locked you will find the timing will be about 14-18 degrees depending on boost, intercooler (air temp) and other engine variables.

Joel