Dissapointment on the Dyno
Thread Starter
Instructor
Joined: Dec 2004
Posts: 175
Likes: 0
From: Athens Alabama
Dissapointment on the Dyno
Went to the Dyno Wednesday, I built an LT1 350 last year and put it in the 94 vette a few weeks ago.
Only made 297 RWHP 301 TQ on the dynojet.
It was 99 degrees and the humidity was high so it wasn't the best time to do it.
I was expecting 320 RWHP or more, but that just didn't happen.
I sent the dyno info and fuel air info to Bryan Herter and I have not heard from him yet, maybe he can squeeze some more out of it.
I didn't replace the fuel injectors yet, they have close to 190K miles on them, so maybe that will help some.
Mods are listed in my sig.
Tomorrow I am running a guy at work with his 02 Trans AM, WS6, at our 1/8th mile strip.
I bet I am going to be dissapointed again....
prattman
Only made 297 RWHP 301 TQ on the dynojet.
It was 99 degrees and the humidity was high so it wasn't the best time to do it.
I was expecting 320 RWHP or more, but that just didn't happen.
I sent the dyno info and fuel air info to Bryan Herter and I have not heard from him yet, maybe he can squeeze some more out of it.
I didn't replace the fuel injectors yet, they have close to 190K miles on them, so maybe that will help some.
Mods are listed in my sig.
Tomorrow I am running a guy at work with his 02 Trans AM, WS6, at our 1/8th mile strip.
I bet I am going to be dissapointed again....
prattman
Melting Slicks
Joined: Oct 2000
Posts: 2,158
Likes: 9
From: N.E. WA
If it was uncorrected, it may not be as bad as it seems. Is this a stick or an auto? Heads also make all the difference. Do you have flow #'s from the port job? Was the AC still on? Good luck with the race.
Race Director
Joined: May 2003
Posts: 10,749
Likes: 41
Originally Posted by prattman
Went to the Dyno Wednesday, I built an LT1 350 last year and put it in the 94 vette a few weeks ago.
Only made 297 RWHP 301 TQ on the dynojet.
It was 99 degrees and the humidity was high so it wasn't the best time to do it.
I was expecting 320 RWHP or more, but that just didn't happen.
I sent the dyno info and fuel air info to Bryan Herter and I have not heard from him yet, maybe he can squeeze some more out of it.
I didn't replace the fuel injectors yet, they have close to 190K miles on them, so maybe that will help some.
Mods are listed in my sig.
Tomorrow I am running a guy at work with his 02 Trans AM, WS6, at our 1/8th mile strip.
I bet I am going to be dissapointed again....
prattman
Only made 297 RWHP 301 TQ on the dynojet.
It was 99 degrees and the humidity was high so it wasn't the best time to do it.
I was expecting 320 RWHP or more, but that just didn't happen.
I sent the dyno info and fuel air info to Bryan Herter and I have not heard from him yet, maybe he can squeeze some more out of it.
I didn't replace the fuel injectors yet, they have close to 190K miles on them, so maybe that will help some.
Mods are listed in my sig.
Tomorrow I am running a guy at work with his 02 Trans AM, WS6, at our 1/8th mile strip.
I bet I am going to be dissapointed again....
prattman
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Team Owner
Joined: Oct 2004
Posts: 81,241
Likes: 3,063
From: altered state
St. Jude Donor '05
Originally Posted by TankerVette
umm... can you tell us a little about the motor (cam, heads, exhaust)? 300 isn't bad if it wasn't modified much...
GM Hotcam
Cloyes double roller iming gear set
1.6 Crane Gold Race roller rockers
EM long tube headers (ceramic coated inside and out)
CSR electric water pump
Stock LT1 aluminum heads ported & polished
Comp Cams (26915) Beehive valve springs/retainers
Cut-back valves and 3 angle valve job (stock valves)
ATI SFI rated balancer
MSD Superconductor plug wires (red)
Upgraded to 95 timinig cover and vented optispark
EGR deleted
Air Injection deleted
NGK Iridium Spark Plugs
Cats Eliminate
Le Mans Master
Joined: Apr 2000
Posts: 5,713
Likes: 105
From: Manassas VA
Well I am going to take a stab in the dark on this one, but something is way off, assuming this is a dynojet and the nos. are corrected. After checking the things such as tune, etc, you may want to double check the cam was installed correctly and not 1 tooth off. There has been a few post on here of people doing that and the power drops are like yours. The other thing is who ported your heads? If someone who is not familiar with LT1-4 heads did the work, sometimes can do more damage then good. Also, did they install bigger valves? FWIW your mods and mine look to be about the same. See signature.
Thread Starter
Instructor
Joined: Dec 2004
Posts: 175
Likes: 0
From: Athens Alabama
I ported the heads, the scope of the job was to remove all of the rough casting and polish like a mirror, on intake, exhaust ports and bowls. Valves are stock. Don't have flow numbers.
I got an email back from Bryan reference the tune. He looked at the dyno info and wideband 02 info and said it is lean. He will add fuel and expects that to bring it up 5-10 hp. Also Bryan said they stopped the pull while the engine was still producing power.
The dyno results were SAE corrected and it was a dynojet.
Will post a link to the dyno info later when I have more time.
The car is a 94 auto, the AC and ASR were turned off.
I guess after I install new fuel injectors and get the corrected tune I will see how things are going, and make another pull. Will also look into the cam install and be sure it is correct.
prattman
I got an email back from Bryan reference the tune. He looked at the dyno info and wideband 02 info and said it is lean. He will add fuel and expects that to bring it up 5-10 hp. Also Bryan said they stopped the pull while the engine was still producing power.
The dyno results were SAE corrected and it was a dynojet.
Will post a link to the dyno info later when I have more time.
The car is a 94 auto, the AC and ASR were turned off.
I guess after I install new fuel injectors and get the corrected tune I will see how things are going, and make another pull. Will also look into the cam install and be sure it is correct.
prattman
Melting Slicks
Joined: Dec 2004
Posts: 2,137
Likes: 5
From: Howard PA
Originally Posted by prattman
I ported the heads, the scope of the job was to remove all of the rough casting and polish like a mirror, on intake, exhaust ports and bowls.
prattman
prattman
I also let the intake port just shy of the OD of the gasket opening. Meaning it doesn't quite go to the scribe lines. I feel it makes a little anti-reversion wall. May do nothing but it's there and in theory it works.
Just some food for thought.
Race Director
Joined: Dec 2002
Posts: 13,348
Likes: 233
From: SCMR Rat Pack'r Charter Member..Great Bend KS
Originally Posted by cuisinartvette
Biography:
GM Hotcam
Cloyes double roller iming gear set
1.6 Crane Gold Race roller rockers
EM long tube headers (ceramic coated inside and out)
CSR electric water pump
Stock LT1 aluminum heads ported & polished
Comp Cams (26915) Beehive valve springs/retainers
Cut-back valves and 3 angle valve job (stock valves)
ATI SFI rated balancer
MSD Superconductor plug wires (red)
Upgraded to 95 timinig cover and vented optispark
EGR deleted
Air Injection deleted
NGK Iridium Spark Plugs
Cats Eliminate
GM Hotcam
Cloyes double roller iming gear set
1.6 Crane Gold Race roller rockers
EM long tube headers (ceramic coated inside and out)
CSR electric water pump
Stock LT1 aluminum heads ported & polished
Comp Cams (26915) Beehive valve springs/retainers
Cut-back valves and 3 angle valve job (stock valves)
ATI SFI rated balancer
MSD Superconductor plug wires (red)
Upgraded to 95 timinig cover and vented optispark
EGR deleted
Air Injection deleted
NGK Iridium Spark Plugs
Cats Eliminate
Nothing else in the list adds significant torque/power.
The "porting" is just amateur polishing that could have hurt as much as helped.
Yes, he's low, but not by as much as he thinks.
Larry
code5coupe
Last edited by rocco16; Jul 14, 2006 at 11:34 AM.
Racer
Joined: Apr 2004
Posts: 487
Likes: 0
From: Huntsville AL
I have stock untouched heads, cam, rr and I got 291rwhp and 326rwtq, so something is very wrong with this so far. My only hp mods are basically a TB and headers. You've seen my full list prattman, so you know what all I have. I'd like to see your dyno chart with a/f. The contact I gave you has taken a break from tuning I think, did you ever contact him? We may could round him up.....
Burning Brakes
Joined: Sep 2000
Posts: 1,199
Likes: 1
From: NewCastle IN. USA
190k on fuel injectors is alot of miles.
odd's are they are way past their prime, and may be the reason your lean.
I'd replace them and anything else on the fuel side (filter and pump) if the mileage is high on them. then head back to the dyno.
bet you pick up 30+ hp
odd's are they are way past their prime, and may be the reason your lean.
I'd replace them and anything else on the fuel side (filter and pump) if the mileage is high on them. then head back to the dyno.
bet you pick up 30+ hp
Race Director
Joined: Dec 2002
Posts: 13,348
Likes: 233
From: SCMR Rat Pack'r Charter Member..Great Bend KS
Originally Posted by Wildcat1
I have stock untouched heads, cam, rr and I got 291rwhp and 326rwtq, so something is very wrong with this so far. My only hp mods are basically a TB and headers. You've seen my full list prattman, so you know what all I have. I'd like to see your dyno chart with a/f. The contact I gave you has taken a break from tuning I think, did you ever contact him? We may could round him up.....
You have RR, he has RR.
You have a cam, he has a cam.
You have headers, he has headers.
You have TB, he has electric WP.
He makes six more hp.
He may be disappointed, but I'm saying he shouldn't be.
Larry
code5coupe