hello

When I examine the PR4 basemap, I see that all the ignition timings are more advanced than the GSR basemap, at all RPMs.

I have a LS/VTEC with a comp.ratio of 9:1.

1. For the motor to work more efficiently with pressure below boost, what basemap ignition parameters should I start with do u think ?

2. When the comp. ratio is lower than stock, isn't there more space for advancing the timing more than the stock ?

 

You need to re-think this carefully. When cylinder pressures are lower than stock, there may be more space for advancing timing. If you are boosting, cylinder pressures will be higher than stock. If you are using a lower heat range spark plug (you probably should be if you're boosting) you can't compare apples to apples anyways.

Go with conservative timing values, then get it tuned!

 

Typically, you can run slightly more timing out of boost than with an NA engine, then gradually pull away timing as you reach atmospheric, then retard .75-1.0 degree per psi. of boost pressure (TYPICALLY)

 

I see..
do you think a GSR map is a good basemap for a LS/VTEC (b18a1+b18c1 head) ?

 

I'm sure alot of people start off with a Gsr map on a p30 base.

 

If you are using the stock GSR manifold, then yes a GSR base will be a good start. If using a Skunk2/blox style manifold, use the P30 (B16) base and adjust the fuel multiplier for the 1797 cc. The GSR map is kinda screwy with the timing around 4-6k.

 

well, actually I use the GSR manifold with the IAB part removed.
so do u think p30 is better to start with ?
I have a neptune on a p28..

p.s. I see that JDM p72 map is much more aggressive than the USDM p72.

can I use the JDM p72 without any problems do u think ?

 

If you no longer have the Iab then copy the maps from the p72 base and paste it onto the p30.

 

my afr was perfect with a gsr map on my lsv, car runs perfect