15lbs boost but only 406rwhp?

[BOOSTER03]

12lbs of Boost and only 401rwhp, 450tq??

Just dyno'd today on a Dynojet. a/f @ 12-12.6 across the board, 21 degree timing, 2.8 upper, cai, o/r x pipe, magnacatback, deltachip.......dropping down to 10lbs (belt slip) over 5k rpm....where do we make our peak HP? I thought with my combo I would be in the 440-460rwhp range?

 

[10thSVT]

You should be around 440-470 with your mods...Sounds like you have a lot of belt slippage...

 

[sndmn_2000]

You should, who did your tune. Your going a little lean with 12.6.

 

[SVT_4_me]

your peak number will probably come somewhere around 6k rpm... the belt slip is killing you. get an idler...

 

[ViciousJay]

pos tthe graph

 

[Snakebite2k3]

ouch.. who tuned it?

 

[BOOSTER03]

I hear that! I will have the graph tonight. It has a deltachip where they are going to do a retune with the revolution chip as we speak. I bought the car with the work done, so I dont know who did what. Gonna go with an idler to keep the boost up......just wondering where the extra 50-60rwhp is?

 

[Snakebite2k3]

with the correct tune, A/F and belt you should be around 460rw give or take

on a mustang dyno youll probably only see 400rw or less. so yeah something is defiantly wrong. keep us updated.

 

[CobraBob]

If you are 12.0 - 12.6 across the board, you are too lean!! You want to be in the 11.4 - 11.7 range. And I'm going to assume you don't have any auxiliary idlers since you haven't mentioned them. If that is true, belt slip is going to be an issue. Posting the dyno sheet will help a lot, but be sure it shows the A/F curve as well.

You probably won't find out who did the tune, so seriously consider getting a custom tune since you know that you have at least an A/F issue. 406rwhp is way low even with belt slip, unless the slip is radical. But you're seeing 15 lbs. up until 5000 rpms, right? Believe me, if this were my car at this point I'd get a good tuner shop to look at my setup, point out other issues that need to be addressed, and above all re-tune my motor -- properly!

Best of luck!

 

[03yellow]

Yep belt slip is killing ya. A/f is not too bad ...Just add a little fuel.

I peaked at 5000-5200rpms, and lost 2lbs of boost; Aloss of 5lbs is hurting your #s.... just ask someone who has added a 4lb lower....... big difference!!!

At least its Easy to fix!!!

 

[droptop351]

needs fuel! belt slippage all the normal stuff that people have already posted
put graph up maybe clutch was slipping

On mustangdyno I was getting 427 with same mods on 78degree day.

 

[BOOSTER03]

Hmmm......just got back from the shop. They re-tuned it and now I am at 452tq and still 405rwhp. He got it in the 11.6 range and was seeing (with new belt installed) 12lbs across the board........it was 86 degrees and humid. How can I tell if its a mustang dyno? I saw a poster on the wall that said dynojet...

 

[SVT_4_me]

I saw a poster on the wall that said dynojet...

then it was most likely a dynojet... did you get a copy of the dynosheet??

 

[BOOSTER03]

Yeah, I have a copy, but my head is hangin low on this one........something is definitely wrong. 12lbs to me shows that I might have a 3.1 upper??

 

[SVT_4_me]

Yeah, I have a copy, but my head is hangin low on this one........something is definitely wrong. 12lbs to me shows that I might have a 3.1 upper??

post it up...

it is possible that you have a 3.1 pulley. get out the ruler and measure it...

 

[BOOSTER03]

Trying to figure out how to post.....even with a 3.1 running 12lbs boost, shouldnt I be over 440rwhp? Is my torque correct in relation to my hp?

 

[Snakebite2k3]

this is interesting. post a pic of the motor or dyno sheet

 

[SVT_4_me]

something is fishy...

 

[SVT_4_me]

maybe something is wrong with their dyno??

 

[03nightmare]

Yeah, I have a copy, but my head is hangin low on this one........something is definitely wrong. 12lbs to me shows that I might have a 3.1 upper??

my car has a 2.8 upper and I have only been seeing 12pounds lately, it is possible. my boost does not drop stays steady at 12psi.