Diablosport question

[ZINC76]

I was wondering why my car runs better w/ the factory Hp tune than the 93 octane predator tune.I have a '01 mustang GT w/ the following:CAI w/ drop in KnN,FMS 70mm T/B,professional products powerflow intake plenum and a UPR off-road X pipe.I spoke to diablosport and they told me that the "diablo tune" is sufficient for my modifications, I was thinking if maybe I'd fee-up the exhaust a bit more w/ a aftermarket cat-back system(currently i have the stock cat-back) or maybe its time for a custom tune.Any feedback would be great. Thanks

 

[twogts4us]

How are you determining that it runs better? What happens when you are driving with the diablo tune?

 

[ZINC76]

The engine seems to rev thru the rpm slower and my mph in fourth gear is at 60mph w/ diablo tune and 70mph w/ factory hp tune.Engine seems to be starving fuel or air.kinda hard to describe

 

[Scorcher2005]

The tune cannot possibly affect your speed. It is mechanically controlled by engine rpm, tranny gear ratio, rear end ratio, and tire diameter. I would check to see that you set the rear end gear ratio input on the tuner correctly. Say you have stock gears (3.08s) and you told the diablo (which tells the computer which sends a signal to the speedometer) that you have 3.55s, it would display a lower speed. And that pretty much matches, as 70mph/60mph=1.16. 1.16 x 3.08 = 3.57. So with you most likely rounding your speeds, I'd put my money on that.

 

[blacksheep-1]

www.racerelated.com

diablosport and sct guys.

 

[2002BLGT]

post up some dyno numbers or time slips from a track would better determine if the car is running slower with the predator tune .......

 

[BurningRubber]

My Diablo tune felt lazy untill I bumped the timing a little bit.

If you do this DONT just advance it all the way like some people claim you can do. Adjust in increments, go out and run the car through the gears and see if it pings/knocks at all. If it does back off the timing. I also added a little fuel to mine because I am afriad it is way lean due to my intake mods yet the Diablosport probaly leans it out a little more when the tune is installed.

 

[Uncle Meat]

The 93 octane tune throws more timing in than the factory HP tune does. None of the canned tunes that come stock with the Predator are all that great though. A custom tune is almost always better.

U.M.

 

[ZINC76]

Replying to the PM about gears, that can't be the problem cuz my car still has the stock gears and I've never missed w/ the axle ratio in the tune, of course this is based on what the seat of my pants feeling not actaul dyno numbers. The car does'nt run bad w/ the "diablo tune" or anything, it could all be in my head.Also I switch my CAI for the stock piece(w/ K and N) to see what happens, I was running a Granatelli high flow aluminum tube for a while and I've heard that some CAI make your car run a little lean or rich depending on your set-up.So for the cars running great w/ the stock rubber intake combo w/ the FMS 70mm T/B and big mouth intake plenum.

 

[BigDave06]

Your posts are hard to understand.

 

[SaleenGT2001]

there is no way a tune can change your top speed in any gear

 

[cobrasvtcoupe25]

Get a cat-back.

 

[twogts4us]

Your posts are hard to understand.

So true!
What does this mean? "The engine seems to rev thru the rpm slower and my mph in fourth gear is at 60mph w/ diablo tune and 70mph w/ factory hp tune" - at WHAT RPM are you talking about??? The same engine speed or ??? This makes no sense unless:
1. Your engine is turning at different speeds or
2. The tunes have different final drive ratios

 

[Scorcher2005]

Like i said before, and as others have, YOUR TUNE IS NOT CAUSING YOUR SPEEDOMTER DIFFERENCE. I gaurantee you accidentally hit a different gear ratio, or maybe it comes with a different gear ratio set on it. Check on that.