here are my mods...(LT1 350)
Ported heads the flow 255cfm on the intake, 194cfm exhaust. CC 305 cam, electric water pump, hooker long tubes, Ram air, borla exhaust, 1.6 rr's, comp R lifters...etc etc. You guys get the idea.

The numbers: 335rwhp, 310rwtq up to 5900rpm with an average air-fuel ratio of 12.7.

Are these normal numbers? What could be wrong? Are my heads crap? (I heard talk of the short turn radius being messed up) Why am I making such low torque numbers?

The car has been tunned (off the dyno) to run pretty well using LT1 edit, and the car ran 13.9 @ 103mph with just a borla catback, K&N and hypertech if that gives you anymore insight.

Thanks, I'm pretty dissapointed for the kind of money I have invested...I hoped for at least 350rwhp and tq.

Andy

 

i could be speaking out of my ****, that doesnt sound too far off...it should be more like 330.

hell, i've got higher compression, more cubic inches, bigger cam, higher flow #'s, and i'm expecting around 350 rwhp.

someone correct me if i'm wrong.

 

i've seen people make up to 350rwhp with stock heads. I would definitely try to check things out. Your torque seems way low also.

 

That is what my heads flowed too, 255/194 @ .600 lift. However, I used the GM847 cam and got the numbers in my sig. Somehow I don't see you picking up 77hp, 61tq just by changing cams. There are many things that could cause you to be down on power, the heads, cam install, compression, spark advance etc. I won't even make a guess

 

What I don't understand is why his TQ #'s are so low. I saw his dyno plot today and he was locked at 310 TQ from 2500 to 5500. I would think with his setup he should be seeing around 340-350 in the midrange (3k-4500).

Andy, your clutch isn't slipping is it?

 

When you say your car was tuned off they dyno do you mean with the Hypertech?

If you have mods (like you do) and your car hasn't been tuned through LT1 edit, Tunercat or sent out PCM out to someone like PCMS4Less that would defently be your problem.

If you have had that done, were you getting any knock retard? When was the last time you did the simple things like plugs and wires?

 

It seems to me that it is very low. You need to get it scanned with auto tap or something to see if it's pulling out timing, although a good dyno operater would probably be able to tell just by the look of the graph. Either that or the clutch theory would defiately cause some low numbers. The numbers in the signature are with stock LT4's on a mustang dyno.

 

what was the stock rwhp on your car?

 

How do your heads flow at low lift? particularly at 300-400 range? It takes more than max flow to make good power and torque. How does your dyno sheet look? Is it a steady power increase or is there a lot of fluctuation in power? Like someone said before you might want to do a diagnostic check.

 

It pulled 295 on a dynojet with the borla cat back.I was actually very disappointed in that number but was very happy with the new ones. I figured it would be 20 or 30 rwhp less especially on a Mustang dyno. His numbers are way low if they were off a dynojet.

 

-I had tuned it with LT1 edit with a friend that is pretty knowledgeable with it. (we did the tuning on the highway the week before the dyno day)
-The air-fuel was at about 12.4 in the top end of the rpm and he (dyon operator) let off at about 5800-6000 in all three runs.
-There is no knockretard because I zero'd it out and only run 94 octain.
-The clutch is high but no obvious slip (I have a Centerforce DF)

I also have the hooker long tubes with the mufflex y-pipe and borla in the open position...could this be why my torque is low?

Any more ideas???

Thank you for your responses

Andy

 

The power curve of hp was growing in a linear fashion all the way until 5800-6000 where he let off.

Torque was FLAT and only lost a small amount from 4400-5800.

I'll see if I can scan the sheet

 

Not to insult you because I made this mistake myself but was the pull made in forth gear? The first time I had my car dynoed a friend of mine and I did ourselves at a speed shop that he uses. He swore that it didn't matter what gear was used so we did it in second and it only pulled 260rwhp and 250rwt. He specializes in 3800 supercharged cars so he doesn't deal with manuals very often.

 

1) get ur knowledgable friend to lean out ur AFR by half a point from peak torque rpm to red line (dont touch the rest)

2) knowing ur knowledgable friend, he loves timing .. ask him what the timing advance he SAW ON THE SCANNER at WOT? not what he put in the tables... ur friend has been crowned the king of tuning by urself and many others so i dont dare speak my opinion .. but too much timing will HURT horsepower

3) see if u can get a flow sheet from jim richmond thru mike ... considering ur cam only lifts .544 .. anything over .550 lift is useless info .. its the low lift flow #s that count. (most likely ur 255 cfm info is at .600 lift)

4) mention to everyone how many Ks are on ur motor ... get a compression test done on all ur cylinders

 

Payam...I asked your opinion, and thanks again. If you would be willing to help in the tunning, I would be greatfull. Good point on the flow of the heads

The pull was made in forth

The car has 172,000KM (not sure in exact miles) but I didn't think that mattered because at 169,000, the car went 13.9 @103. I would assume that the bottom end, although not great, isn't the limiting factor in my #;s