I was wondering if I should retune my car? When I tuned it I was running it straight downpipe. Now I put a three inch exhaust. When I tuned my car I made 300hp and 220tq on b18b. Noticed a power drop but don't how much.

 

It will run slightly richer with the exhaust on. Definite power loss will be noticeable. Good power numbers BTW

 

the difference between open downpipe and 3" at that power level should be minimal do you have a wideband o2? if so have your afr's changed much?

 

 

same thing i did i tuned with dump n next day i did a 3in exhaust n it felt laggy alil

 

It does seem to run richer. Do you guys think I should retune or waste of money for that little difference?

 

A retune shouldn't cost you that much, call your tuner and see what he thinks and what he''ll charge to change the tune.

 

if you have any other parts you would like to get put on, IE. intake manifold, injectors, maybe race gas? Then you should get those parts in and go back for a tune.

 

Alright gonna call tuner to ask if worth to tune over. I am gonna gonna put anything else for the moment.

 

do you run a wideband? if so what are your afr's in boost after the change?

 

Yea I run a wideband. Usually at idle I am in the 12:1 range.

 

jesus 12:1 range at idle who tuned your car? its worth retuning

 

^which a/r ratio at idle should be?

 

14's 15's not 12's

 

yea that rich, like said above aim for 14.5-15.5 at idle, 11.5-12.0 in boost for pump gas depending on your set-up and tunners guts

 

+1, what are you AFRs in boost

 

took it to get it retuned. First i got 300hp and 220tq open downpipe. Put a 3 inch exhaust and started to run rich so i got it retuned made 308hp and 255tq. runs way better now worth it.

 

CHARTS

 

thanks for the graphs, whats done to the LS?
My del sol with an LS should put down similar but higher HP.
Im surprised running a 3" exhaust bumped up your torque that much.

 

It has stage 2 cams and valve spring and retainers. Rc 550cc injectors.

 

wow, same here. I got the crane all motor stage 2 cams, crower springs and retainers and same injectors.

Took it to the dyno today, my dizzy was on its last legs, kept on breaking up.

I would love to see some videos on how it rips.

 

So what did it make on the same boost as the open downpipe with the full exhaust?