Got some REALLY bad dyno results..
Thread Starter
Le Mans Master
Joined: Oct 2002
Posts: 7,178
Likes: 1
From: Bahston Mass.
Got some REALLY bad dyno results..
As posted earlier this summer, I put the '95 under the knife this Spring. I've already emailed Nathan, hoping to pick his brain, and possibly get to the bottom of this issue, but here's the deal..
Ported LT4 heads/intake
Hotcam
1.6 RR's
An array of new parts (Opti/plugs/wires, etc..)
EM Lt's & hi-flow cats.
Anyways, to make a long story short, the before / after dyno results were REALLY embarrassing. I won't even get into them here, they are so bad. Certain parts of the run indicated a bad tune (PCMForless did it, twice). I was running a bit lean, and the #'s on the graph are ALL OVER THE PLACE. From 2000 - 4500 RPMS, I made decent power(Decent being the key word), then the HP/Torque DROPPED LIKE A ROCK at 4500RPM's.
I called Bryan, to see what was going on.. his suggestion was that the tune is ok, but to check the plugs/wires and rockers(they might be too tight). My problem with that is that the car is running LIKE A TOP - If any of these things were wrong, the car wouldn't be running this well.
I planned on posting the #'s here tonight (A/F #'s), but I left my dyno sheets down the cape, so I'll have to reprint them tomorrow.
Any ideas?? I'm PRAYING it's a timing issue, and other tune related things, but for now, I have no way of knowing.
Thanks, in advance.
Ported LT4 heads/intake
Hotcam
1.6 RR's
An array of new parts (Opti/plugs/wires, etc..)
EM Lt's & hi-flow cats.
Anyways, to make a long story short, the before / after dyno results were REALLY embarrassing. I won't even get into them here, they are so bad. Certain parts of the run indicated a bad tune (PCMForless did it, twice). I was running a bit lean, and the #'s on the graph are ALL OVER THE PLACE. From 2000 - 4500 RPMS, I made decent power(Decent being the key word), then the HP/Torque DROPPED LIKE A ROCK at 4500RPM's.
I called Bryan, to see what was going on.. his suggestion was that the tune is ok, but to check the plugs/wires and rockers(they might be too tight). My problem with that is that the car is running LIKE A TOP - If any of these things were wrong, the car wouldn't be running this well.
I planned on posting the #'s here tonight (A/F #'s), but I left my dyno sheets down the cape, so I'll have to reprint them tomorrow.
Any ideas?? I'm PRAYING it's a timing issue, and other tune related things, but for now, I have no way of knowing.
Thanks, in advance.
Thread Starter
Le Mans Master
Joined: Oct 2002
Posts: 7,178
Likes: 1
From: Bahston Mass.
It was as choppy as hell.
I wish I could post the #'s tonight, but I can't. Before/After yielded a 9 HP gain, and a torque gain of 20. Disgusting.
Bryan claims I should make good power to 6300 RPM's, but I make nothing after 4500.
AF dropped down to 12.7 at the end, and started around 14.3 - I'll post EXACT #'s tomorrow - I'm pissed that I left them down South. I can't get copies until lunch time.
There is NO WAY this thing is tuned correctly.
I wish I could post the #'s tonight, but I can't. Before/After yielded a 9 HP gain, and a torque gain of 20. Disgusting.
Bryan claims I should make good power to 6300 RPM's, but I make nothing after 4500.
AF dropped down to 12.7 at the end, and started around 14.3 - I'll post EXACT #'s tomorrow - I'm pissed that I left them down South. I can't get copies until lunch time.
There is NO WAY this thing is tuned correctly.
Race Director
Joined: Jan 2002
Posts: 12,263
Likes: 86
From: O'Fallon Missouri
Valvetrain
Make sure the valves are adjusted correctly. Had my car on the dyno last week, and it would fall off at 5800 rpms, and then come back around 6200. The dyno operator suggested the valvetrain may need adjustment. Well, on the last run, I colapsed a lifter and broke a pushrod. The pushrod actually poked a hole in the valve cover. When I pulled the engine apart, the rocker on the affected cylinder was way too loose.
Also, without even touching my WOT fuel, it was almost perfect on the dyno runs. I did lean it out just a touch, and pick up a little HP.
Good Luck.
-Mike
Also, without even touching my WOT fuel, it was almost perfect on the dyno runs. I did lean it out just a touch, and pick up a little HP.
Good Luck.
-Mike
Thread Starter
Le Mans Master
Joined: Oct 2002
Posts: 7,178
Likes: 1
From: Bahston Mass.
Thanks Mike.
The buider was actually the same guy who dyno'd it on Saturday. After my call to Bryan, he pulled the VC's off and checked the rockers - They were perfect.
I'm at wits end, because this thing is running incredible - It sounds great, and feels great. I almost didn't believe the #'s, then I saw the chart, and it was up and down like a roller coaster till it hit 4500 and just hit the bottom.
The buider was actually the same guy who dyno'd it on Saturday. After my call to Bryan, he pulled the VC's off and checked the rockers - They were perfect.
I'm at wits end, because this thing is running incredible - It sounds great, and feels great. I almost didn't believe the #'s, then I saw the chart, and it was up and down like a roller coaster till it hit 4500 and just hit the bottom.
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Drifting
Joined: May 2003
Posts: 1,730
Likes: 1
From: Charlotte NC
St. Jude Donor '05
Originally Posted by JB666
It was as choppy as hell.
I wish I could post the #'s tonight, but I can't. Before/After yielded a 9 HP gain, and a torque gain of 20. Disgusting.
Bryan claims I should make good power to 6300 RPM's, but I make nothing after 4500.
AF dropped down to 12.7 at the end, and started around 14.3 - I'll post EXACT #'s tomorrow - I'm pissed that I left them down South. I can't get copies until lunch time.
There is NO WAY this thing is tuned correctly.
I wish I could post the #'s tonight, but I can't. Before/After yielded a 9 HP gain, and a torque gain of 20. Disgusting.
Bryan claims I should make good power to 6300 RPM's, but I make nothing after 4500.
AF dropped down to 12.7 at the end, and started around 14.3 - I'll post EXACT #'s tomorrow - I'm pissed that I left them down South. I can't get copies until lunch time.
There is NO WAY this thing is tuned correctly.
Why are you so quick to blame the tune? Its a hotcam tune something that we have literally done probally 2000 of. It sounds like you got some problem somewhere. If you post a datalog or dyno sheet we can help you find it.
Hate to tell you this, but theres nothing really a tune can do to drop hp and Tq drastically. If its dropping more than 10rwhp its definately not the tune.
Pro
Joined: Nov 2004
Posts: 698
Likes: 1
From: louseyville Ky
Hmm, that really concerns me since I have installed my cam and will be putting my EM long tubes on really soon. I have a lot of the same parts waiting to be installed when my schedule gets cleared out a little more. I will be interested to see the graph when you post it. I am sure we can figure something out. When was the dyno last calibrated and what kind was it?
Thread Starter
Le Mans Master
Joined: Oct 2002
Posts: 7,178
Likes: 1
From: Bahston Mass.
Originally Posted by Alvin
Why are you so quick to blame the tune? Its a hotcam tune something that we have literally done probally 2000 of. It sounds like you got some problem somewhere. If you post a datalog or dyno sheet we can help you find it.
It's not that I'm quick to blame the tune, but everything else has been double and triple checked. The only thing left is a tuning issue.
I'm not saying there couldn't be something missed - but things like plugs/wires aren't an option - They are 100%.
I'm also the one that was told 100X "Do not get a mail order tune, get it done locally, it'll be much more accurate".
I know you've done 2000 Hotcam Tunes - I'm not saying you screwed up, just that I'm VERY frustrated here.
Thread Starter
Le Mans Master
Joined: Oct 2002
Posts: 7,178
Likes: 1
From: Bahston Mass.
Originally Posted by 96dblblack
Hmm, that really concerns me since I have installed my cam and will be putting my EM long tubes on really soon. I have a lot of the same parts waiting to be installed when my schedule gets cleared out a little more. I will be interested to see the graph when you post it. I am sure we can figure something out. When was the dyno last calibrated and what kind was it?
It's a Mustang Dyno, and only put in about 9 months ago. When it was last calibrated, I will find out.
I still can't believe, even by the FEEL of it, that the #'s are correct.
You guys will have to see these #'s.
Drifting
Joined: May 2003
Posts: 1,730
Likes: 1
From: Charlotte NC
St. Jude Donor '05
By the sounds of it you may have a tranny issue.. Have you taken it out and punched it? Does it feel like someone slamming on the brakes at 4500rpm? If so theres something the 700r's do about centrifically locking clutch the next clutch pack... I myself sufferd from this problem once and have seen a few cars doing the same thing.
Its characterized by a severe dip (around 50-125 hp) somewhere in the powerband.
Really theres nothing that a tune can do that can cause a dip greater than about 10hp. Even if it runs in to huge amounts of retard it won't "DROPPED LIKE A ROCK" like you described.
Its characterized by a severe dip (around 50-125 hp) somewhere in the powerband.
Really theres nothing that a tune can do that can cause a dip greater than about 10hp. Even if it runs in to huge amounts of retard it won't "DROPPED LIKE A ROCK" like you described.
Race Director
Joined: May 2003
Posts: 10,749
Likes: 41
Originally Posted by JB666
I already did... 10HP gain from all the mods. Still under 300 HP.
sorry, i have no clue what your dyno #'s were before u started all the mod list.
what rwhp at what rpm?
what rwtq at what rpm?
and what kind of power were u hoping for? mustang dyno typically less, just no sure what percentage less.
Melting Slicks
Joined: Nov 2003
Posts: 2,679
Likes: 1
From: South Amboy NJ
hey i sunk in over $2k into heads and cam and othere little odds and end to get 323rwhp and 343rwtq on a 93 auto lt1. i went from running dead consistent 14.0's at 99.9* to running high 13's at 101...
i have a similar problem tho...my power drops off after 5300 rpm
spill yer beans so maybe we can all get this figured out
i have a similar problem tho...my power drops off after 5300 rpm
spill yer beans so maybe we can all get this figured out