Still not sure why you're not happy with the gain with just a catback. Like everyone else has said don't get cought up in numbers . I make 287 WHP on what I'm being told now is a inconsistent machine ( mustang) Al tho it's the lowest machine around and I sont mine that.
Just for you're arguments sake I went to another shop to get some pulls done becaue the place I use was booked and I made a WHOPPINH 252 WHP ! So did I really go backwards from stock ( 265 ish) no the machine was differnt and actually found out later was set up wrong. Numbers are number that's it dyno's are a tunning tool and not bragging rights. Yes it would have been great to see a higher numbers but the numbers you got are just that numbers . Be happy and keep modding . You can use the same dyno just compare the gains and not the end WHP .

OP (and everybody else):

Provided you use the same dyno, whatever kind it is, and use the same correction factor, and dyno in the same gear (again, 4th is fine -- less stress on the motor), you can always determine magnitude of gains or losses by the percent of change from your baseline (of course, that means you need a baseline...).

In other words, absolute values are less meaningful than the delta (i.e., a gain of "5 whp" isn't as clear as a gain of "3% from baseline"). Likewise, don't dismiss gains under the curve over peak gains.

A good way to evaluate overall change is to look at the % change where hp and tq cross (i.e., 5252 RPM).

Peak values are only critical for drag racing time and and top speed, but for daily driving and your "butt dyno", you will be more aware of changes much lower in the powerband, and off the line most of all.

Thought I would update the thread just so you know I took advice:icon17::icon18:

I mentioned earlier than I had Z1 intake tubes , I actually had some Mishimoto ones which arent as good quality as the Z1 ones and since my tuner reckoned the MAF readings were a little screwy I ordered some HPS ones (incidentally there is very little difference between the two) to be sure.

Also bought some Berks test/decat pipes and fitted those

So before was 309.4 flywheel HP

After just fitting the above parts it produced 328 flywheel HP but it had leaned out .....a lot !

After an Uprev remap and smoothing it made 345.9hp. +36.5hp increase

http://i80.photobucket.com/albums/j1...psm4fnvce8.jpg

The car drives a lot better especially at the top end and ultimately that's what's really important , I will however get a run done on a dynojet dyno to compare at some point

So thanks all

Thats better like 285 WHP , nice man

Haven't seen a Dyno read flywheel HP. You'd have to subtract 17% for an automatic & 15% for a manual @ the wheels.


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Alternatively you can just read the print out prior to the set correction factor the DD dynos adds on to give estimated fwhp ;)

I only posted the flywheel figures to give an accurate comparison

I have never bought the idea of transmission losses being a set percentage , if you double the horsepower of an engine do you really double the transmission losses?

That be a Yep!
A baseline average that is calculated is 15% loss of power at the wheels due to friction,etc...through all moving parts.
An automatic seems to lose about 17%
This number will vary from type of vehicle....but ultimately averages out to 15%.
So if you're putting down 500hp @ the wheels...you're close to 600@ the crank.
:)

Mine is right at 17% pending 332 crank hp. Not sure if drop in K&N filters helped any....here's video in 5th gear 1:1 speed limiter tripped in at 156, 1st run was in 4th gear & spooked the Dyno guy when the shift light flashed just over 7k & he backed out.https://vimeo.com/140489018


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