I have a lsvtec 81.5 wiseco pistons eagle rods gsr head supertech springs and retainers and type r cams. gsr lsd tranny. ebay gt35r. made 451whp at 17psi and im having troubles keeping the turbo spooled up between gear changes while drag racing. I tried using the quick spool settings on s300 with a 3 port solenoid but it didn't help much. in the logs I can see it only start building over 10psi at 5500 and above so it feels laggy between shifts. any advice would be greatly appreciated thanks.

 

1.) That's a biggish turbo for your power level. I would guess it is not within it's highest efficiency range which will make it feel slow.

2.) You should not be dropping below 5500RPM between shifts. And with a bigger turbo, it is critical that you stay in the higher RPM range to keep it spooled.

3.) I would look into full throttle shifting, and maybe a GT3076R.

 

What RPM are you revving too?

 

around 8000 cutoff is set at 8200

 

Yeah at that RPM you will not be able to keep the turbo where it needs to be, I would raise your RPM cutoff to 9,500 if your motor can take it. This way when you shift hopefully you don't go under 5,500.

 

Or use a smaller turbo at such low boost pressures

 

I went from a t3 t4 57 trim ebay turbo at 24psi to the gt35 maybe I just went up too big in size for my needs. I dont drive the car on the street at all it has a 3.5 inch hood exit so I thought I would be alright for when I wanted to increase power later on

 

Yep. Time to increase boost pressure or ya went too large

 

Correct.

 

I’m just not sure how adding more boost will help with my lag? Like if I run more boost pressure it will take even longer to spool up no?

 

no because the charger will be spinning faster while it makes more boost. so when you shift the turbo shaft will be spinning faster then it currently is. why are you shifting at 8000? with your rod and piston set up you should rev higher and it will not lag so bad. what id do is keep turning the rev limit up til your gear change drop falls to 6000 rpm or so. zeal auto cal. will help you figure it out a lot.