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View Full Version : When to Tune ?


beerkat
07-05-2005, 08:26 AM
I have just started doing some mods that might effect my tune. I have the K&N filter and the Borla cat-backs. A freind of mine says that the engine might start to run lean and I should get it tuned. Thoughts anyone?

0103SVT
07-05-2005, 08:41 AM
With exhaust and a K&N you will be fine. Most people get a tune when they upgrade pullies, fuel system, and stuff like that.

blk04cobra1
07-05-2005, 01:57 PM
More than likely you will be fine...If it were me, I would get on a dyno, just to see what kind of numbers it puts down (make sure to get an A/F reading also) and check the A/F to make sure it's not running lean...just a peace of mind thing, I guess...with those mods, i'd venture to say you're in the 410-420rwhp range :cool:

InfamousSVT
07-05-2005, 04:50 PM
I have just started doing some mods that might effect my tune. I have the K&N filter and the Borla cat-backs. A freind of mine says that the engine might start to run lean and I should get it tuned. Thoughts anyone?

With just a filter and a cat-back, I would not worry about it. Don't waste the money on a tune with those mods unless you just want to. With those mods it will definitely cut out the restrictions that the stock cat-back has and free up some air-flow, but not to the extent of having your engine run lean.
Throw a pulley on that thing and get a dyno tune, then you can see how much better it breathes!:D

Have fun with your modding:thumbsup:

kilroy
07-06-2005, 08:40 AM
With just a filter and a cat-back, I would not worry about it.
+1

There's always power to be found by tuning, but comparatively insignificant with the few mods planned. I'd personally wait for the pulley - and then put it on the dyno for tuning.
There's also more power to be found at the fingertips of a competent tuner versus anything you could do with the handheld. Rocky (RR03COBRA) got an extra 25rwhp. Reason? The tuner's software is much more complex than the high level tuning the handhelds provide. I'm not bashing the do-it-yourselfer, just suggesting that when you do go for a tune to go through a reputable shop & you won't be sorry.

smashedheadcat
07-06-2005, 09:09 AM
On my '03 cobra with a borla stinger catback and open 9'' K&N filter I put down 400.2 rwhp and 370.1 rwtq. The a/f was a steady 11.5 :1 until 4300rpms and then it dumped rich off the chart (richer than 10:1). I guess it goes rich as the computer schedules extra fuel flow to cool the cats on a sustained wide open throttle run (like on the dyno). So with the factory tune, that feature will keep your car on the safe side. Way conservative still. You will not need a tune until you either pulley the car, change the mass air meter, injectors, and possibly headers. Getting rid of the cats with an off road mid-pipe will cause the check engine light to come on, but a tune still wouldn't be required. A set of MIL eliminators will keep the check engine light at bay in that situation.

I do recommend however, that anytime you add power, it is definately a good idea to have the a/f checked out on the dyno or, by using your own wide band o2 sensor such as this one. www.widebandcommander.com This will tell you what is going on with the car, and will let you know right away whether a tune is required or not.

beerkat
07-07-2005, 08:24 AM
Thanks All for the replies. :thumbsup:

cobra330
07-07-2005, 08:28 PM
The way our engines are set up..you don't need to worry about a tune yet...although a few more mods..and you will want a tune so, you can take advantage of all the mods togehter..

The exhaust alone has "uncorked" some of the back pressure..which helps..to a small extent the engine run a bit cooler..and certainly provides some more HP...along with the CAI.