IH8FORD

iTrader: (6)

This will be a long one. First for what the car has.
6.0 iron block 408 , 10.9-1 comp. ported l92's, Patric G cam it is a custom grind I will post the specs if he chims in here and says its cool.
GMPP intake with elbow. ported intake.car has a 12 bolt rear and 13.50-15 et streets and a th350 w/ a 3400 PI nitrous converter. Motor looks like this


Had some real low dyno #'s 404 rwhp and 498 RWTQ and on a 100 shot it made 536.2 and 533.5 heres the dyno sheet. I have held off on posting these #'s until I had some problems nailed down.

So far I have found out that my cam was installed 2 degrres retard when it should have been installed sraight up and I havent seen any good results out of that elbow on NA applications so I have a 4150 accufab on the way for it. So anyone wanting the elbow and throttle body for a turbo or supercharger build you can get a good deal on it PM me any offers.

Any suggetions on things to look for would be helpful. right now I have the front cover off so I can set it up dot to dot. Hoping betwwen the throttle body and improper cam setting that I will have found the missing power.

black01_WS6

iTrader: (13)

what size of longtubes- it won't make a big difference but can give about 10 rwhp if you have the 1 3/4

IH8FORD

iTrader: (6)

Kooks 1 7/8 long tubes.

Pray

iTrader: (7)

It looks like Jeff leaned you out to 14.00:1 afr which is hurting you if it a real number. That is going to hurt your motor in the long run. Try what you are doing and add some fuel.

IH8FORD

iTrader: (6)

I am taking it back because it is fouling plugs out too. I had some issues with the car up there so I had to take it back anyway.

ls2 bait

iTrader: (11)

well u have some tune issues but also be reliastic in the fact that you are using a power robbing tranny/ converter combo as well as slicks which can skew dyno number greatly. dont get too upset run it and see what she does.

OUTLAWZ RACING

iTrader: (9)

Way lean! good luck those l92 heads are a trick when it comes to cams.

94 guy

iTrader: (125)

how big is the cam? i just dynoed my 408 l92 th350 yank 3600ss and it went 465. the cam is small.

IH8FORD

iTrader: (6)

pretty big the shift rpm is supposed to be 7200.

gametech

iTrader: (1)

The things that I "think" I see in those dyno graphs are converter flash, tire spin (on the nitrous hit) and an inaccurate wideband. This makes diagnosis hard. Beyond that, it looks like an exhaust restriction. An intake restriction could cause the same problems, but is normally found easily enough to not have to ask. That has to be the weirdest NA torque drop I have ever seen.

JonCR96Z

iTrader: (33)

The cam is 24X/25X. Per PatG's email it is textbook design for single plane intake w/ a 300 shot in mind. Obviously the elbow isn't helping the numbers and its a nitrous combo so motor numbers aren't going to be as good, but still seems like it should be more.

The cam doctor shows the ICL is as speced by PatG, what kind of loss could be had from the cam being install wrong?

The car runs like it has 400hp (or less) but probably due to the plugs being fouled.

Ryan L

If the 14:1 tune was done on purpose, that guy needs to get his *** kicked.

Seriously.

JonCR96Z

iTrader: (33)

The converter flash is the cause of the weird torque curve, but IH8FORD has an LT1 car that on the same dyno makes similar torque (same transmission setup) and only 40 rwhp less with a vastly inferior motor. I really don't know about the wideband being innaccurate. I had my car in there recently and it seemed to be right on at the time.

Slowhawk

iTrader: (12)

I would much rather see that graph in MPH instead of rpm but there are a ton of variable's. One possible problem might be the Cam.I've been seeing a ton of people lacking hp by running too big of a cam with the L92 heads.Mix that with the high flow intake which will stall the inlet air bad.For comparison we have a 408ci close to your build running a 228/236 Cam pushing 500rwhp unlocked.

BORN2FLY

iTrader: (76)

Your #1 problem Tune(r)!!!!!!!!!!!!!!!!!!! You need to make a trip over to Mooresville,NC!! Pm sent.

IH8FORD

iTrader: (6)

I will first get the cam set up the way it was meant to be run before I go changing it. But I have been seeing better #'s with the smaller cams I just assumed that it was because the l76 intake couldnt support the airflow of the larger cam. I am hoping with this accufab TB and the cam set up right and the tune fixed it I will make a serious improvement.

Patrick G

iTrader: (14)

You're going to have to give me the name of the person who originally requested this cam. I cannot find a Travis in any of my files. FWIW, I rarely spec cams for L92 heads with more than 15 degrees of overlap at .050" so I'm going to have to see what the reason would be for specing one that would have duration in the 24x/25x range. Let me know and I can give you some more feedback.

blu1

problem #1, Jeff Creech touched the car.

IH8FORD

iTrader: (6)

John Ridge ( joncr96Z) ordered the cam for me because I was in Iraq at the time and we were trying to get this thing ready to go for when I got home.


This is a copy of what you sent us. Dont get me wrong this isnt a cam bashing thread If anything I think the cam is the least of my problems. Any help will be appreciated.

The attached cam recommendation is a textbook approach to cam design with a single plane intake. When running a GMPP single plane, you're going to want to open your intake valve about 4 degrees earlier than running an L92 intake and it will want a few more degrees of duration. The ideal intake valve closing point for a motor of your size is around 49-50 degrees ABDC at .050" when running the single plane and L92 heads.

This cam is biased more toward nitrous performance than on motor. This is the reason for the large advance and big exhaust duration. When running a 250-300 shot, I tend to keep the intake open and close the same as running on motor, but make the exhaust open earlier and close later. The only problem with this cam is that it will not have a light chop. Rather, it will have a hard lope. The challenge is giving you the maximum performance that a single plane manifold deserves without giving the motor proper overlap. Your motor will have the street manners of a 346 running a G5X4 or an MS4. While those cams are streetable, they are not classified as having light chop.

A cam that would have a lighter chop would look entirely different and may not perform as well, but if you'd rather go that direction, just let me know and I will resubmit the cam recommendation.


Cam recommendation: (1999 F-body with 408, L92 heads, .040” gasket, GMPP single plane intake, 1 7/8” headers, TH400 with 10.5” stall, hard lope, 40% strip/60% street, 93 octane, 200-300 nitrous, 7200 rpm peak, 7500 rpm rev limiter)
247/259 .656”/.663” 112LSA +6 advance
Comp Cams LSK/LSK lobes
2132R/2135R HR112LSA +6 advance (106 installed intake centerline)

Patrick G

iTrader: (14)

OK, now I see the recommendation. From July 2007. As you can see from the explanation and the dyno sheet, this is a nitrous-biased cam (200-300 shot). The curve of the 100 shot dyno show that your valve events are consistent with what will pull into the 7200 rpm range, but the pull is not as clean NA. This leads me to believe you're getting an intake restriction. Could be the intake elbow. Not many people have performed well with them on single planes unless they're running forced induction or nitrous. It would be interesting to see how you'd run with an Accufab top-mount throttle body.