Head cam lt1 not making NEAR estimated power.
11-11-2008, 01:34 PM
#41
TECH Apprentice
Thread Starter
iTrader: (2)
Join Date: Aug 2008
Location: Central Illinois
Posts: 364
Likes: 0
Received 0 Likes
on
0 Posts
A friend of mine ended up getting a mail order tune when he did his 383 build. He went to the track and ran consistant 13's and couldn't figure out what was wrong. took it to get a dynotune and picked up 80rwhp. that's why I'm getting mine dynotuned this winter. I've also got a H/C car and it runs low 13's... I know that it's in the tune.
11-11-2008, 03:53 PM
#42
Im runnin a mail order tune on my 383. I recently made some changes that required a new tune, my old tuner is no longer in business. I had bryan at pcm for less do the tune. I know there is plenty left in it, but it still is runnin good! I know for a fact that a bolt-on ls1 will be lucky to come within a bus length. Point is, I don't think the tune is costing you as much as some are claiming! You might be leavin 20-30whp on the table from a mail tune, but you should still be rapin a bolt-on ls1. You need to scan your car and see whats going on!
11-11-2008, 03:59 PM
#43
TECH Apprentice
Thread Starter
iTrader: (2)
Join Date: Aug 2008
Location: Central Illinois
Posts: 364
Likes: 0
Received 0 Likes
on
0 Posts
I've talked to a guy from straightline performance up in new lenox, illinois. They run a mustang dyno rather than dynojet. I honestly don't know the difference between the two.. But he said he would start off by hooking it up to wideband and see whats going on with that run couple pulls, if it needs to, then tune it from there..
Oh and I never did replace my coil, I just figured it was fine.. Should I do that before I take it to be dyno'd. And opinions on mustang dyno? Reason I question it is because Ion said to take it to a dynoJET only..
Oh and I never did replace my coil, I just figured it was fine.. Should I do that before I take it to be dyno'd. And opinions on mustang dyno? Reason I question it is because Ion said to take it to a dynoJET only..
11-11-2008, 04:29 PM
#44
TECH Enthusiast
iTrader: (19)
Join Date: Apr 2006
Location: Morris, IL
Posts: 607
Likes: 0
Received 0 Likes
on
0 Posts
the difference between a dynojet and a mustang is that the mustang is closer to actual conditions. the mustang simulates things such as drag and takes into account how heavy the car is from what I have been told. If I am wrong, someone please speak up.
11-11-2008, 05:55 PM
#47
TECH Enthusiast
iTrader: (19)
Join Date: Apr 2006
Location: Morris, IL
Posts: 607
Likes: 0
Received 0 Likes
on
0 Posts
SpeedInc doesnt do obd1 anymore, they contract it out. I think he has Ion come out and do it. you have to wait till they get a couple of obd1 cars together and then he comes out and does them all in the same day. Only reason I know is because I called Larry to talk to him about it last month and that is what he told me
11-11-2008, 06:55 PM
#51
Rocker adjustment and a proper dyno tune are HUGE.
Spring selection comes back to bite people a lot too, weak springs and overtightened rockers kill top end power.
FWIW
I picked up 30rwhp between my street tune (many hours of driving and tuning) and Ed Wright's dyno tune.
The mail order tune I got from another vendor was so bad I couldn't even run it on the dyno.
(In retrospect, I should have ordered the mailorder from Ed to begin with, I don't know what I was thinking)
Make sure your plug wires are not arcing.
Make sure the header gaskets are not leaking.
Have clean air and fuel filters.
You could also connect a laptop to the diag port and do some datalogging to see what's going on.
You may find that you are pulling a crapload of timing due to burst knock or something equally annoying.
Degreeing the cam is important IMHO.
I've had cams off by 6* ... I've also had them within 1*
The point is that you want to get 100% of what you paid for in buying a custom cam
and you can't really expect to tune for a cam when the specs may not be as expected.
Fortunately, a dyno-tune can help overcome part of that issue by tuning for whatever the car is setup with.
Don't feel too bad, many people deal with the same thing when installing H/C (no matter which vendor they buy from)
You feel angry, depressed, you want to pull your hair out .... then all of a sudden, you
have that AHA moment and you find the problem. That's what you get that ****-eating grin
that no one can wipe off your face.
Spring selection comes back to bite people a lot too, weak springs and overtightened rockers kill top end power.
FWIW
I picked up 30rwhp between my street tune (many hours of driving and tuning) and Ed Wright's dyno tune.
The mail order tune I got from another vendor was so bad I couldn't even run it on the dyno.
(In retrospect, I should have ordered the mailorder from Ed to begin with, I don't know what I was thinking)
Make sure your plug wires are not arcing.
Make sure the header gaskets are not leaking.
Have clean air and fuel filters.
You could also connect a laptop to the diag port and do some datalogging to see what's going on.
You may find that you are pulling a crapload of timing due to burst knock or something equally annoying.
Degreeing the cam is important IMHO.
I've had cams off by 6* ... I've also had them within 1*
The point is that you want to get 100% of what you paid for in buying a custom cam
and you can't really expect to tune for a cam when the specs may not be as expected.
Fortunately, a dyno-tune can help overcome part of that issue by tuning for whatever the car is setup with.
Don't feel too bad, many people deal with the same thing when installing H/C (no matter which vendor they buy from)
You feel angry, depressed, you want to pull your hair out .... then all of a sudden, you
have that AHA moment and you find the problem. That's what you get that ****-eating grin
that no one can wipe off your face.
11-11-2008, 07:32 PM
#54
TECH Enthusiast
Join Date: Nov 2005
Posts: 520
Likes: 0
Received 0 Likes
on
0 Posts
The valve train is noisy as ****, mainly on driver side though, i have tightened them down with it running might do it again to double check. Pushrods are 7.15 length I was told that they'd work fine with setup. As far as I know all plugs are good, wires are perfect. I timed it "dot to dot" so it's in the same position it was in with the stock cam. The car vibrates alot, tuner says it's cam surge though, which makes sense. That shouldn't hurt my power though.
11-11-2008, 07:42 PM
#55
TECH Enthusiast
iTrader: (19)
Join Date: Apr 2006
Location: Morris, IL
Posts: 607
Likes: 0
Received 0 Likes
on
0 Posts
The reason I ask is because my heads were milled slightly but I was told that the stock length (7.200 I believe) would be just fine, so that's what I went with.
11-11-2008, 07:44 PM
#56
11-11-2008, 08:01 PM
#57
Lloyd sent me this when I asked
PR length is something that you need to check to get the EXACT length. Use an adjustable PR checker and start at 7.100" and adjust the length until you get the wear pattern most centered in the valve. Go .050" shorter and watch the wear pattern move. If it gets worse, go .050 longer. It could be anywhere from 7.00 to 7.250 depending on everything done but a 7.100" (Trik Flow 21407100) is what I suggest for people that do not know how (or do not wanna take the time) to do this. The following is a method of verifying proper valve train geometry. After you have estimated the required pushrod length using a Pushrod Length Checker, use this method to verify that the valve train geometry is correct (using the rockers you are using in your engine):
1
The first step is to install a solid lifter and an adjustable pushrod. Mark the tip of the valve with a marker
2
Install your rocker arm and set it up with zero lash.
3
Rotate the crankshaft clockwise several times. Remove the rocker arm. The contact pattern of the rocker tip will be where the marker has been wiped away from the valve tip. The pattern should be centered on the valve tip, and as narrow as possible. If it is not, experiment with varying the pushrod length to yield the best pattern.
4
Pushrod Too Long: Notice how the pattern is wide, and shifted to the exhaust side of the valve tip.
5
Pushrod Too Short: Notice how the pattern is wide, and shifted to the intake side of the valve tip.
6
Pushrod Length Correct: Notice how the pattern is narrow and is centered on the valve tip.
Lloyd Elliott
972-617-5671
ElliottsPortworks.com
Sorry the pics didnt work but i can forward the e-mail! If you need it!
PR length is something that you need to check to get the EXACT length. Use an adjustable PR checker and start at 7.100" and adjust the length until you get the wear pattern most centered in the valve. Go .050" shorter and watch the wear pattern move. If it gets worse, go .050 longer. It could be anywhere from 7.00 to 7.250 depending on everything done but a 7.100" (Trik Flow 21407100) is what I suggest for people that do not know how (or do not wanna take the time) to do this. The following is a method of verifying proper valve train geometry. After you have estimated the required pushrod length using a Pushrod Length Checker, use this method to verify that the valve train geometry is correct (using the rockers you are using in your engine):
1
The first step is to install a solid lifter and an adjustable pushrod. Mark the tip of the valve with a marker
2
Install your rocker arm and set it up with zero lash.
3
Rotate the crankshaft clockwise several times. Remove the rocker arm. The contact pattern of the rocker tip will be where the marker has been wiped away from the valve tip. The pattern should be centered on the valve tip, and as narrow as possible. If it is not, experiment with varying the pushrod length to yield the best pattern.
4
Pushrod Too Long: Notice how the pattern is wide, and shifted to the exhaust side of the valve tip.
5
Pushrod Too Short: Notice how the pattern is wide, and shifted to the intake side of the valve tip.
6
Pushrod Length Correct: Notice how the pattern is narrow and is centered on the valve tip.
Lloyd Elliott
972-617-5671
ElliottsPortworks.com
Sorry the pics didnt work but i can forward the e-mail! If you need it!
11-11-2008, 08:31 PM
#58
TECH Apprentice
Thread Starter
iTrader: (2)
Join Date: Aug 2008
Location: Central Illinois
Posts: 364
Likes: 0
Received 0 Likes
on
0 Posts
I was going to check the fuel pressure tonight but the parts store was closed when I got there, so I guess I'll just have to wait until tomorrow to check that.. I got the lt4 km in today and Ion was correct about it not making a difference. Oh well, another part to add to the mod list I guess haha!
11-11-2008, 08:54 PM
#60
You can tighten them up a bit and quiet them down and sacrafice top end power.
I think 1/4 past zero (true zero, not "I can can't twist them with my fingers") is about as far as one should go.
I think the OP may get more info if we had a dyno graph to look at
the shape of the curve and the A/F results tend to common highlight issues pretty quick.