HP loss in T5 trans. w/3.55 gears?

Ed Calvert · Oct 2, 2004

Hey,
Took my 95 to the dyno after installing the trick flow H/C/I kit and got 257hp @ 305ft/lbs. torque at the rears. How can I figure out what the flyweel hp is? I was somewhat dissapointed in the #'s. The guy running the dyno backed my timing down to 10 degrees BTDC (I had it at 14) and increased the fuel pressure to 44lbs. at idle(I had it set to 39lbs.). I still have the stock headers and CAT.'s. The shop told me I neede to replace these with high flow and then I should be able to sqweek another 20 or so hp. Any thoughts?

Thanks,
Ed

S/CBlack95GT · Oct 2, 2004

The car will normally lose around 15% through the drivetrain. So you are making around 300hp at the engine. Adding headers and losing the cats would easily gain at least 25rwhp.

HazMat404 · Oct 2, 2004

did you have pinging with the 14* of timing?? 14* is a great start for most stangs if it can handle that much timing. you running any higher octane than normal?? i personally think 44psi on a stockish car (from the sound of it, yours pretty much is) is a complete waste and will only waste gas and hurt power. on a stockish car, no more than 40psi should really be used.

edit: god i was preoccupied when i read that. didnt see the hp and h/c/i

Grn92LX · Oct 2, 2004

Why did that guy lower your timing back to stock? That cost you power fyi. That combo WILL like anywhere from 14-20* initial. Mine likes about 18*. Track/dyno verified. I recommend longtubes and an offroad H pipe. More timing and the exhaust will get you near or at 300rwhp.

I did 304hp/339tq with the tfs combo but that was with junk shorty headers and a way too small 65mm tb.

Ed Calvert · Oct 2, 2004

Thanks for the replies. Well, The guy running the Dyno claims that he got 4 more horses out of the thing by reducing the timing from 14 to 10. His target was a fuel/air ratio of 13.1 above 3000RPM which he did(I'm looking at the dyno printout as I'm typing this). I don't know enough to know if that's a good # or not. The only thing that I do know is that after he monkey'd with the fuel pressure regulator and timing the engine idle is all over the place until it warms up. I think I'm going to put the timing back to 14 and lower the fuel pressure back to about 40PSI. The shop that ran the dyno told me that the long tube headers are best BUT the installation is more of a 'pain in the rear' than the short equal length headers. I've never done it so I don't know. Know of where I can get a good deal on high flow CAT's? I've got the H-Pipes sitting in the shed. I had to pull them off because we just started emissions testing in York Co., PA. The headers with the flowmasters where pretty damn loud inside the car as well. The High flow CAT's might be better for me.
Thanks for all the replies once again.

HoofnIt · Oct 2, 2004

What kind of dyno was it? If it was a Mustang dyno then the hp will be a little low. That combo should be making more hp.

mo_dingo · Oct 2, 2004

On pretty much stock exhaust, and 10* timing, that sounds about right.

Get the timing back to 14*, get some good headers & o/r midpipe, and you will see 300rwhp. I have to do emissions this month, so the stock h-pipe goes back on sometime next week for testing, and goes back to storage afterwards. Sucks, but worth to 100%.

Leave the fuel where it is. 13.0-13.5 is the optimal a/f ratio when you are WOT. Anything less/more than that will cause a loss of power.

Don't worrk about your flywheel numbers. They don't mean crap. The accessories, trans, d/s & rear end all have drag. The only real numbers are what you put down to the wheels.
Scott

hbk_136 · Oct 3, 2004

To answer your first question, to find your flywheel hp, divide your rear wheel hp by about .8-.85 and you will get your flywheel hp. (.8-.85 depending on how much loss, usually its only 15% so i would use .85)

257/.85=302.4 fwhp

sldghmr · Oct 3, 2004

Ed Calvert said:
The shop that ran the dyno told me that the long tube headers are best BUT the installation is more of a 'pain in the rear' than the short equal length headers. I've never done it so I don't know.

I installed a set of BBK longtubes and I am positive that it was the easiest header job I've ever done. Unequal length shorties are pretty easy also, just gotta pull the O2's so you don't accidently break them. With the collectors being under the car there is no blind reach to place washer/lock washer/nut combo on with one hand. Oh yeah, the longtubes were a breeze. Only thing is if your into beauty, then your gonna need a friend to hold one up until you get the header bolts started. I didn't care so I layed mine against something and then attached the bolts from the top. You could probably use some wood blocks and rags or something but your gonna bang them around a little bit by yourself....good luck.

Ed Calvert · Oct 3, 2004

Thanks for all of the replies. I'll ga ahead and push the timing back to 14* and get rid of the stock exaust. Well, one thing for sure that I've learned with this 95GT project car....HP=$. As soon as I get the new exhaust on I'll rerun the dyno and post.
Thanks again.

final5-0 · Oct 3, 2004

Ed

If you run cats make sure the dyno guy knows about them cause they will show a leaner ratio when using the sniffer type of wb that most dynos use.

I also agree with the others about the stock exhaust manifolds and mid pipe. They are causing you to leave power on the table.

I would like to see your complete combo.

Why not just put it in your sig? It would help everybody to answer any Q's that you might ask.

Later
Grady

HP loss in T5 trans. w/3.55 gears?

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