Best mods for engine perforemaance HHR SS
Senior Member
Joined: 04-26-2009
Posts: 669
From: City of Champions
Step1
Modifying the stock DP, is all that is needed to remove the 'restriction', of the stock exhaust system.
Using an 18" piece of 2.75" tubing, with slight pressure, move the tubing, side to side, to 'core' a hole thru the 2nd cat.
This leaves some of the cat guts, which will stay in place, & will get hot like a normal cat, so if an inspector feels the outside of the cat, it feels like a normal cat.
It will pass emission testing also.
That 1st cat is really important, to keep the intake tract/piping, 'charged', which keeps torque at the highest level, for DD, at low, non-boosted RPMs.
Hay, it works for me.
I've tried different high flow cat/cat less DPs, & none keep the low end torque high, like the modded stock DP.
Step2
Add a K&N intake tube & filter. , to remove the intake restriction.
Step3
Add a Turbo-Tech engine mount. , to 'plant' the power.
Step 4....Tune it Any tune will do , GMPP, Trifecta, HPTuner.
Now you have a muscle car, that will run in the 13s, all day long.
Just add a E47.5 tune / slicks, & run in the 12s, all day long.
It's so easy to make these buggys go...
Modifying the stock DP, is all that is needed to remove the 'restriction', of the stock exhaust system.
Using an 18" piece of 2.75" tubing, with slight pressure, move the tubing, side to side, to 'core' a hole thru the 2nd cat.
This leaves some of the cat guts, which will stay in place, & will get hot like a normal cat, so if an inspector feels the outside of the cat, it feels like a normal cat.
It will pass emission testing also.
That 1st cat is really important, to keep the intake tract/piping, 'charged', which keeps torque at the highest level, for DD, at low, non-boosted RPMs.
Hay, it works for me.
I've tried different high flow cat/cat less DPs, & none keep the low end torque high, like the modded stock DP.
Step2
Add a K&N intake tube & filter. , to remove the intake restriction.
Step3
Add a Turbo-Tech engine mount. , to 'plant' the power.
Step 4....Tune it Any tune will do , GMPP, Trifecta, HPTuner.
Now you have a muscle car, that will run in the 13s, all day long.
Just add a E47.5 tune / slicks, & run in the 12s, all day long.
It's so easy to make these buggys go...
Thread Starter
Joined: 12-17-2008
Posts: 3
From: texas
She is at 109K and going strong!
BTW it is a 5 speed.
Senior Member
Joined: 08-07-2011
Posts: 553
From: Montebello, CA
Senior Member
Joined: 07-23-2008
Posts: 321
From: ny
