compression test

[CCgt03]

so what the hell is going on here -

breakdown -

front left cylinder - 160 --------- front right - 160

161 ---------- 175

155 ---------- 175

couldnt get the back left coil pack off --------- 170

it put down 260 hp 285 tq tonight....i dont know whats going on.

mhiggs beat me tonight too....i had him till 70-75 and then he drove right by me...i thought i was goin good too...that should be right where the cams are making good power in 3rd gear. I dont think he should of been able to drive by me like that....but it was a good race...no hard feelings.

[CCgt03]

heres a list of all my mods -

mild P&P heads
3 angle valve job
vt stage 2 n/a cams/manley nextek valve springs
msd coil packs
bbk cold air intake
bbk long tubes
bbk x-pipe
magnaflow magnapacks welded in with borla tips
ford raing H/O oil pump
03/04 cobra clutch
3.73's

and tune.
i know i need the plenum - t/b and I want to get some pullies. even without that....matt shouldnt have been able to pass me the way he did....I had a nice shift into 3rd...still ahead of him... and then he cruised right by me.

[CCgt03]

matt post up what u have done Id like to compare.

[NotoriousGreaseMonkey]

Those compression numbers are ALL over the board. I would like to see a leakdown test to find out where the pressure is going. I wonder if the cams are degreed in right....

[sstony]

king cobra ftw! lets race biotch

[Gt]

I just e-mailed Scott @ VT about this. The car is way down on power for what it has. You should be close to 300 rwhp, maybe not over till you change the plenum/tb.

[Slow ET]

:nx:

[Azn Kenny]

Yeah I was just about to ask, was Mhiggs spraying??

[Snow]

+1 for leakdown test - you've got somewhere around 13% variance from highest to lowest cylinder... and I believe 10% is about the max variance you should have...

[Mhiggs]

Yeah I was just about to ask, was Mhiggs spraying??

I sold it a few months ago. :D


matt post up what u have done Id like to compare.

Mac CAI, P.P. 75mm TB and plenum, Mac Longtubes, 3" off-road prochamber, 3" flowpaths with turn-downs/dumps, Ford Racing Aluminum driveshaft, 3.55's, 11" clutch (Stage 1/Factory upgrade), and it was custom tuned at Jaws Racing obviously.

I told the guys to put in 3.55's but when tony changed the speedo calibration for me he thinks they are 3.73's. I have no clue now so I will find out. But right know I am siding with tony.


Yeah I shifted into second and it did nothing but spin. He got about a car to a car and a half ahead at that point. Then I caught up and was a car ahead by the time we got to whats her names truck. I need a new locker and new syncros. Oh and my race with pat ended up with me beating him by about 1 1/2-2 cars. But he doesnt have anything done to it.

[Gt]

Runfile_007 (Blue line) is Matt's car.
Runfile_011 (Red line) is Craig's car last night
Runfile_010 (Green line) is Craig's car with the 02's Accufab inlet setup

[04ctsvfl]

craig. I bet that one the spark plug blew out of is going to even be lower. Open up your exhaust (all of it) I know you still have a few pieces of factory pipes down there with all those welds, get the tb and plenum, degree those cams, and ur shit will be haulin asssss

[Greg Kulbick]

VT cams don't need to be degreed like Comps, but they are marked Left and Right.

[Gt]

VT cams don't need to be degreed like Comps, but they are marked Left and Right.

Don't *need* to be, but it's worth checking.

[NotoriousGreaseMonkey]

That compression is going somewhere....I agree on checking the camshaft positions just in case. If they are one tooth off it might be just enough...

[CCgt03]

so what do i do for the leak down test??

[NotoriousGreaseMonkey]

so what do i do for the leak down test??

I was talking to one of my techs today he said since they are over 150 you might not be able to find anything on a leak down.. But there are 2 ways to do it. 1 is to make sure the valves are closed on the particular cylinder you are working on and just shoot air into it and listen to where it comes out..either the intake or the exhaust or thru the oil filler.. Or have a shop do it and they should have a gauge that will tell where it is leaking down at.

[Gt]

so what do i do for the leak down test??

Also it doesn't have to be a leak down test per say, just need to pump air into the cyls and listen where its coming out. exhaust/intake/crankcase etc. If it's the exhaust/intake then the valves are open at the wrong time (need to pump air into the cyl at TDC on the compression stroke). And if its the crankcase/valve covers then the rings are shot. I'm guessing you will be getting the air out the intake/exhaust.

[04ctsvfl]

From VT regarding the issue:
The stock gears have no adjustability for degreeing unless you modify them, but you can still degree the cams in to check where the stock gears have them set. Some guys will file the keyway to allow some adjustment (the torque of the bolt holds the cam in place anyways). That said, I'd say 90% of my customers just line up the dots like they did with yours without issue. But technically, yes you can degree them in.

With the ported heads, I agree, you should be in the 295-310 range, assuming you have a throttlebody/plenum upgrade and exhast work. Degreeing the cams will definately tell you where the cams are installed at. Its possible your gears are some of the 'really off' ones (meaning one side could be 2degrees advance, the other side 3degrees retarded, etc). It could also be in the tune as well. Who did the tune on the car and what's the a/f like. We'll figure it out, just may take some back and forth emails.

sounds like we need to take apart an engine..... :hobo:

[Gt]

Yup, I've been chating with Scott @ VT about it also. They think based on the compression test #s, that it would be possible that the driver side cam is off a bit.

[CCgt03]

had robby go through it today at mazda -

did 2 compression tests - all were 175-180
checked the cams.
took the cam gears off made sure they were ok.
counted all the links on the chains to make sure that was right too.
checked the plugs.
made sure the cams were on the right sides.

and.........everythings fine.

[Gt]

Well we know you need the intake stuff, that is holding you back. But I still feel the power is way down. I've seen another car with similar problems years ago. It was a 97 Gt and he got ported heads, and still only made the power of a bolt on 02 Gt. His heads were ported wrong.

[sstony]

His heads were ported wrong.

man that's it. throw your stock heads back on with the new cams and see what happens. or buy a set of cnc ported ones.

[NotoriousGreaseMonkey]

Fuck that. Its time for a blower..or enough nitrous on it to euthanize(sp) a small town.

[Gt]

man that's it. throw your stock heads back on with the new cams and see what happens. or buy a set of cnc ported ones.

I really hate to say that's it, but its about the only other possibility. Even with the Accufab/JLT setup and tuned in. It would be ~25 rwhp behind the 02 with similar mods.

[Gt]

mild P&P heads Ported PI Heads
3 angle valve job same
vt stage 2 n/a cams/manley nextek valve springs VT Stage 2 cams/ Comp springs
msd coil packs Stock
bbk cold air intake JLT CAI
bbk long tubes Hooker Headers
bbk x-pipe Hooker X-pipe
magnaflow magnapacks welded in with borla tips Bolra XR-1's dump'd
ford raing H/O oil pump stock
03/04 cobra clutch Had a Mcleod clutch, now auto
3.73's 4.30s



Mods in black are the 02 mods

edit:uploaded dyno graphs
Both the 02 pulls are with the Cams/headers/intake.
whetstone.10 (blue line) is before ported heads
whetstone.14 (red line) is after ported heads
runfile11 (green line) is Craig's current setup
runfile10 (purple line) is Craigs with the 02's intake setup

Based on those graphs, it's like he is running stock unported heads.

[CCgt03]

pics of heads.

[Gt]

Got any pics of the combustion chamber?

[sstony]

the question also to be answered is did king cobra actually put those heads on your car.

[Mhiggs]

Would it be possible that they ported/polished the heads too much? I have heard from numerous people that bigger is better but only to a certain point and you will actually lose power. Just a thought.

I would call whoever did the P&P and see what they say and then call the people that installed it as well.

[CCgt03]

only other pic I have...of first valve job. before buddys 3 angle.

[CCgt03]

stony- king cobra would have had to swap valve springs if they kept those heads...I would have blown a stock valve spring by now if they didnt. I dont think they did all that.

[Gt]

Ah, I see now. They gasket matched the ports and didn't touch the chambers. Yeah, get the intake and you will be about all your are going to make with those heads.

here's the 02's chambers
http://www.blownstangs.com/misc/2005/heads/valves.jpg

[CCgt03]

who did yours tony?

[CCgt03]

vt stage 2's - on sale $945....flows 225/190. hummm.......

[Gt]

Herb Yancer @ Competitive Edge Racing Cylinder Heads in Sarasota, FL 941-809-1866

[Gt]

Who did the gasket matching on those heads?

[CCgt03]

Who did the gasket matching on those heads?

shit I didnt see this till just now-

RPM in crystal river, Florida.