Need a little help guys

[Yellowpnoy]

I finally got my car to the track last night to make a few passes. This was the first time that i had ran it with the new motor and trans in it, and although i know it has a lot of potential, i just need a few pointer as to what would cause a problem like i had with the car. First off the track wasnt hookin at all, but easing it out of the hole with a slow roll on the throttle it yanked a 1.72 60' time. The problem i am having is that the car runs out of steam after say 4500 rpm. I mustered an 11.98 out of it but at only 113mph. I am tuning with a PMS and i think i can go a little further with the timing but i dont want to mess with that yet because i think there is another problem that needs looked at first. Here is my setup:

Dart blocked 427w
Brodix 225cc CNC Heads
Comp Cam XFI 236 cam .579/.579 236 int./248 exh. @.050
Edelbrock Victor EFI ported to match 90mm TB
Anderson 4" Power Pipe
PMAS Velocity 95mm Meter
Accufab 90mm TB
Hooker Super Comp 2" Primary Headers
Crower Valve Springs 116lbs seat pressure/389lbs open
255lph Fuel Pump/stock lines
C4 trans with 3600 stall
3.73 gears
Moser axles

The first thing i want to look at would be the valve springs. I did a search online and found a test that 5.0 mustang did on these and they used the comp 977s which have a 160lb seat pressure and are about 430lbs open, because they said that big hydraulic rollers need pressures like that so they dont float and that they were just enough, which is a pretty big leap from where mine are. I looked up that part number on summit and they have them. Would you go higher on the seat/open pressure if the ones i posted above were just enough for the test?

Fuel pressure remained fine during the runs and the A/F was in check according to my wideband. I think that the valves started to float out hindering the upper rpm potential, because the thing was a rocketship until about 4500 where it started to run out of steam. Any ideas? Thanks!

Anthony

 

[cenok is family]

here's an idea...post pics of that motor and car! 427...

 

[86bluecobra]

seems kinda odd that you would start to float at 4500rpm. It looks to me like thats when that setup should start pulling.

 

[86bluecobra]

you know after doing a little more research ya I guess you could be floating at 4500rpm. still seems a little low but take for instance my vic jr heads. They come with a spring rated at 145lbs closed and 320lbs open. They claim 8000rpm on these springs. The springs with 115 and 280lbs respectivly claim 5500rpm. It does look to me like you are infact using a spring that does not have the force in lbs that you really need. Look into getting bigger springs.

 

[Yellowpnoy]

Cenok, here are some pics!

86bluecobra - To be honest, i am not positive that it was 4500, i was focusing on other things at the time, it may have been a little over 5000. From what i am gathering, being that the duration is so long on the XFI cams, that you need a high spring pressure to keep everything under control. I am with you, that is where this thing should be pulling like a freight train, but unfortunately it didnt, thanks for your help man! I will look into this!

Anthony

 

[86bluecobra]

very nice looking car and engine my friend. How did you end up getting the springs you have? Were they the recommended ones from comp cams? If not maybe give em a call and have a chat with a techy. If they did recommend those springs then maybe talk to a professional engine builder.

 

[Yellowpnoy]

No they werent recommended by an engine builder. I looked at the brodix website and got their specs of the track 1 heads with the hydraulic roller springs in them. I bought the heads off ebay and ordered the wrong part # and got the heads with the mech. roller springs installed which were about 550lbs open pressure. I called summit and gave them the specs and he gave me the part # for the crowers that i have in the heads now. I dont think he took into account the size cam that i would be running. I think i will just call comp tomorrow and see what they recommend to me to use. You can take a look at the webpage with the test of these cams in this link if you care to look.

http://www.mustang50magazine.com/techarticles/m5lp_0608_xfi_roller_cam_test/engine_dyno_testing.html

Everything on the intake/exhaust side flow extremely well, so i dont think that is the problem. Thanks a lot for the advice!

Anthony

 

[86bluecobra]

I remember that article. Sounds like a good spring for those cams. I bet comp will agree. Hope you get it all sorted out soon. The other thing I was having a problem with was the cam itself. It almost seems like you need more cam. Are you trying to keep it streetable? I guess if it has all that duration it doesn't need a heck of a lot of lift though. but those are huge heads and a big displacement. Hope you get it all sorted out soon.

 

[5spd GT]

Look at your cam card and see what spring is requries with the spring seat pressures and opening points, and match them up Nice engine and car!

 

[Yellowpnoy]

Thanks for your help guys!

86bluecobra- I called comp cams and asked them if that would be a good spring to use and the tech agreed with me on that. He said that the 977's should be perfect. When i ordered the motor i had the engine builder have comp grind a custom cam based on the needs that i wanted, and they ground a cam with just about the same lift numbers as the XFI off the shelf grind which is .579/.579, but the duration was higher on the custom cam at 308/318 adv., and the xfi was 286/300 which helped me pull more vacuum at a decent idle.

Thanks for all you help with everything, i will let you guys know what happens!

Anthony

 

[86bluecobra]

good to hear mate. Hope it starts pulling like a bastard now past 5000rpm.

 

[Yellowpnoy]

Thanks a lot! I just gor the springs in the heads, the ones i had in there were a mofo to get out, the keepers were stuck and didnt want to come out at all, and the motor only has about 300-400 miles on it. I should have it up and running this weekend and i will take it out for a spin. Thanks a lot for your help!!

Anthony

 

[86bluecobra]

Well I want An update if that was indeed the issue. I hope thats all it was.

 

[Yellowpnoy]

I hope so too, but if its not, oh well, it needed the springs anyway. Could be a fuel issue, hell, it could be something that i dont have right in the PMS. I need to take it to the track on a nice saturday and make some passes. The fuel pressure reads about 39psi with the vac line attached, i am going to make some blasts and just make sure the fuel pressure is staying up, it could be running out of fuel, i am not sure how much a single 255 intank and stock lines and rails can feed, becaust its pretty demanding as far as fuel is concerned on the top end and i hope its not sucking the rails dry. If thats the case...time for a full glenns performance fuel system!!

Anthony

 

[86bluecobra]

I doubt it is a fuel issue because didn't you say you were still rich on the wideband air fuel ratio?

 

[Yellowpnoy]

Yea, the warning light never came on when was running, and i glanced at it and it was right around 12.8-13.1.

Anthony

 

[86bluecobra]

That definetally still a good mixture you have there. BTW what kinda power is this combo producing? Was it ever dyno'd? I actually think you haven't had it on the dyno because the possible valve float would have showed up there instead of the track. Would be nice to get some numbers on that engine. I guess if I had the wieght of your car we could throw the times and MPH in a calculator and figure how much Hp your making.

 

[Yellowpnoy]

Well, i did take it to a Dyno, but the dyno operator who supposedly knew how to tune with the PMS didnt know s**t about it and i got uncomfortable and took the car home, never made it above idle, so i bought a wideband and street tuned it, got great tune for it online that got me in the ballpark and went from there. My goal is to get a custom cam from Jay Allen or Ed Curtis this winter to install, because i am sure that i can get away with a lot more cam. I figure the car weighs about 3000lbs, the backseat is taken out along with all the radio stuff and that sort. I beleive with this combo it should make somewhere around 450-480rwhp, but that doesnt show in the MPH only because i didnt get any RPM out of the car.

Anthony