Wondering what you guys think my numbers will be after
the installs this coming Thursday.
2006 Mustang GT.

Here's the list of mods:

4.10 Ford Racing Gears
C&L Racer CAI
Ford Racing Hot Rod Cams
BBK Long Tube Headers
BBK High Flow Catted mid X pipe
SLP loudmouths
Custom Dyno Tune 91 oct.

HP and Torque guesses?
Thanks!

 

the dyno is probably gonna read low because of the gears, but i would say 320 rwhp and 330rwtq. At the track i bet you will break 12's with good tires.

 

So are you saying I will read 320rwhp with the gears on the dyno?
Or the dyno will read lower than 320 because of the gears and the real number would be 320?

 

Also... is it true that with rwhp you add 17% to get HP to the crank
so if i was reading 320 rwhp I would be reading 374.4 at the crank?

 

From that list, the only mods that will net you noticable HP on the dyno are the CAI, cams and (most importantly) the tune. Your exhaust mods won't really make a dent at your power level. I'm not too familiar with the potential of the hot rod cams, but assuming they are fairly aggressive, I would expect between 310-320 at the rear wheels.

 

The common estimate that people use for manual transmissions is 15% drivetrain loss. That's just a guess and far from scientific (not to mention no two dynos are the same), but for bench racing purposes, 320 at the rear wheels of a 5 speed is about 370 crank.

 

Really?
EVERYTHING I have read says that Long Tubes make a BIG difference in the gains you can get from cams.

 

The LT's will help with the cams. My car on a Mustang dyno made 348 HP and 333 TQ with the same basic setup.

 

You'll get most of your power from the cams, not the tubes. The stock exhaust flows very well on the S197 mustangs. There is very little backpressure to overcome on a naturally aspirated setup.

 

There is a lot of controversy as to whether any exhaust mods make a difference on these cars. The reason is, you NEVER see someone dyno before and after on LT headers without also making a tune adjustment for AF ratio and spark advance..

The people selling headers want people to buy them, so they will NEVER show results that actually reflect power gains without something else affecting the power, like a tune.

I have only seen one before/after with nothing else modified (other than turning off rear O2s and calibrating front O2s for longer leads after relocation) from a manufacturer, and those tests were all done under boost, so they may not be valid on NA cars. That test was done by Kenne Bell and they took the stock exhaust over 600rwhp with ZERO gains from headers, high flow cats, mufflers, and even headers with open pipes. It isn't until close to 700rwhp they started to see gains.

The key is in the tune.. anyone that tells you that LT headers require a tune for anything other than O2 sensors is wrong. Headers don't change the AF ratio or affect spark timing, and if either of those 2 things are changed in a tune, the power differences are from those changes, not necessarily the headers.

Here is the test we need to settle this once and for all: Start with stock (2005-2010 3v 4.6). Tune it to get the most power. Dyno, record numbers. Install LT headers. Make changes to tune only for O2 sensors so you don't throw a code. Now dyno again and compare.

My money is on the two dynos being nearly identical with maybe a slight change in the torque curve and peak points for hp and torque. Last year I recall seeing some dynos posted on some forum (don't recall which) where the tests were pretty close to this. In those dynos, torque tended to drop 2-3 ft-lbs and hp tended to go up 2-4 hp, and in both cases the peaks had moved up in RPM.

Keep in mind, HP is dependent on torque and RPM. If you start with a red line of 6500 rpm, you have to test again at the same RPM or you are skewing the results..

I would like to think that LT headers make a difference on our cars, as so many people have dropped a lot of money on them. Until I see proof that isn't skewed, however, I will consider headers a sound mod.

As far as cams with LT headers go - I am willing to believe it as soon as someone uses the above methods of proving it. Dyno after cams and tune are in place, then add LTs and dyno again without adjusting power factors in tune and show the results. If there is a gain, I will be convinced.

I would expect to see 320-330 rwhp on most dynos with the mods you describe. Depends on where you start though, and since every dyno is going to be a little different, I would dyno before and after on one dyno, preferably under similar weather. The less "adjusting" you have to do for ambient temp, humidity, etc the better. It's the only way you can be sure of your actual gains.