Tune Question
Thread Starter
Intermediate
Joined: Sep 2007
Posts: 43
Likes: 0
Tune Question
I had my local tuner tune my car after I installed a set of E.T. Perf. 2.5 heads and a Torquer 3 cam in my C5. While he was tuning it he drilled a 7/32nd's hole in my throttle body blade to get it to idle right. Is this a common practice or should he have taken more time with the tune to get it to idle right? It also rev's to 2800 r.p.m's when I start it cold in the mornings and that can't be good on the new springs. Am I just just being paranoid or is there a problem with the tune or tuner? Any help would be great!!
Former Vendor
Joined: Feb 2007
Posts: 2,572
Likes: 1
From: Austin Texas
No need to drill the C5 throttlebody. I have tuned a LS7 making 600 rwhp and did not touch the throttlebody and this one has a 248/254 0.640/0.630 111 LSA cam. There are several things that need to be adjusted like the running airflow table, fueling and spark tables, start up airflow tables to name a few.
Le Mans Master
Joined: Mar 2004
Posts: 5,562
Likes: 5
From: South East coast Florida
No need to drill the C5 throttlebody. I have tuned a LS7 making 600 rwhp and did not touch the throttlebody and this one has a 248/254 0.640/0.630 111 LSA cam. There are several things that need to be adjusted like the running airflow table, fueling and spark tables, start up airflow tables to name a few.
...goes back to the old drive by cable/IAC days to help tune the idle IAC count to a reasonable level at closed throttle. Our drive by wire (DBW) setups can now regulate the throttle blade opening to perform the same function. The RAF, timing and Thottle follower (will act as our old style dash pot 
) are the two most important parameters to help settle down a large cam application at idle.
Former Vendor
Joined: Apr 2007
Posts: 1,331
Likes: 4
From: Jacksonville Florida
Yep, cable or drive by wire, there is absolutly no reason to EVER drill a TB, its a hack way to get by without spending the time to properly modify airflow tables, get a new tuner and make him replace your TB blade.
Drifting
Joined: Jan 2005
Posts: 1,517
Likes: 0
I don't know that there is anymore to say, two VERY competent tuners have said it all... He might not be a bad tuner, just not up to date on the latest stuff... I'd find another shop and hope he didn't drill a really expensive TB..
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