Where's the HP?
 

Just installed TR224/224 .563/.563 112lsa, March underdrive pulley and dyno tuning, gained only 13 RWHP and 5RWTQ. Previous set up is in signature. I am really dismayed I figured 20 HP most likely 25 HP. Original HP was 390 after install 403. I know the dyno is low 5-6% as per the shop, but my concern is the small gain. Ideas?

what cam did you have before the swap?

Sorry, I thought it was still in my sig. It was a Comp 216/220 .525/.532 114lsa. Wouldn't you think going from mild to moderate would have done better? Thanks

were both dyno runs performed at the same shop?post a dyno graph if you can.what was your A/F ratio and total timing after the tune?

hows about the power under the curve?
possible valve float?
post the graph

By no means am I an expert but that sounds about right, particularly if they typically dyno low there. You didn't really have all that big of a jump in cams, on a good day between those cams I could see maybe gaining 20 HP but now more. So you're about right in there. Also, IMHO Underdrive pulleys show more at the track than on the dyno.

That's about right for a mild to moderate cam swap... people go from a 224 type cam to a 230+ cam and only gain 5-10 rwhp for the swap. So I imagine going from a 216-218 type cam would be similar when going up to a 224.

:werd:

Thanks guys, here's some more info, power under the curvegained nothing until 5,000 RPM. I dynoed at the same shop that I have for years Norris Motorsports in Orlando.There was no valve float I've got dual 978's. AFR was 12.8-12.9. Timing was fine I think around 28* with no KR. A Comp adjustable timing chain was installed. Comments?

The comment is what has been said previously... You didn't make a big enough jump in cam size to warrant the gain you were expecting. The two cams you swapped are too close to each other in duration and lift for those kinds of gains... You should have gone with something like a G5X-3 or T-Rex for a ~25 rwhp gain.

My 2c.

Blake

bingo

I talked to Paul at Thunder Racing, He said a 13 HP gain with the cam upgrade and pulley was definitely too small. He asked if the HP was peaking at around 5,700 RPM which it was, so he told me that the timing should be retarded -2* and that would bring peak HP up to around 6,100 RPM. Mike Norris also said if there was any more HP to be found a timing change might be the solution.