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Author
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Topic: Help find missing 70rwhp...
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Jeff S
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Member # 371
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posted
 
 
A buddy of mine dyno'd his car today. The combo is a 331ci w/ 10.5:1 compression, AFR 185's, Edelbrock RPM intake, XE 274H cam, 70mm TB, BBK cold air, BBK 1 5/8" LT's, 2.5" exhaust and a T-5.
I would expect this combo to make somewhere around 350rwhp.
It only put out 275rwhp/300rwtq. Timing was at 32* total and the AF was 13:1. Adjusting the timing/fuel didn't make more than +-5hp difference. It made peak HP at 5400 and the torque curve was VERY flat and peaked around 3800. The curves were all smooth with no spikes or quick dropoffs of power.
ANY IDEAS???
[ February 12, 2004, 09:22 PM: Message edited by: Jeff S ]
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'90 Mustang LX: 8.53 @ 157.92 w/ 1.33 60' on DR's
'10 ZR1: FOR SALE
'14 E63 S: RENNtech ECU
'04 Gallardo: UGR TTG
Posts: 2121 | From: San Jose, CA | Registered: Aug 2001
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BlackNGold
CaliforniaFords.com
Moderator
Member # 655
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posted
Does he have a catted mid pipe?...Clogged cats?..If the A/F and timming is cool, then there must be a restriction somewhere in the air-flow, right?...Was his clutch slipping?...What size MAF?
Those numbers seem REALLY low....
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-SLOWER TRAFFIC KEEP RIGHT-
Posts: 5132 | From: Bay Area, CA | Registered: Dec 2001
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Jeff S
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Member # 371
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posted
It's got off-road exhaust, no MAF(DFI), the AF and timing were perfect.
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'90 Mustang LX: 8.53 @ 157.92 w/ 1.33 60' on DR's
'10 ZR1: FOR SALE
'14 E63 S: RENNtech ECU
'04 Gallardo: UGR TTG
Posts: 2121 | From: San Jose, CA | Registered: Aug 2001
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wilit
Mustang Messiah
Member # 3367
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posted
This may be a stupid question, but what type of dyno was it tested on? I know Mustang dyno's are notorious for giving underated HP & Torque numbers. Generally 10-15% lower than what you'd get from a Dynojet.
Also, what's the valve train like? All roller? What type of valve springs? Did you degree the cam? What size injectors is he running?
[ February 12, 2004, 09:44 PM: Message edited by: wilit ]
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"If a man hasn't found something worth dying for, he isn't fit to live." - Martin Luther King Jr.
Posts: 4793 | From: 37.78514° North 122.40100° West | Registered: Oct 2003
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BlackNGold
CaliforniaFords.com
Moderator
Member # 655
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posted
Was the cam "degree'd"?...I would think that the peak rwhp numbers would be higher than 5,400rpm...An RPM Intake can support power all the way to 6,500rpm and I'm sure the 185 AFR's and the XE cam would take him at least to 5,900rpm...
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-SLOWER TRAFFIC KEEP RIGHT-
Posts: 5132 | From: Bay Area, CA | Registered: Dec 2001
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BlackNGold
CaliforniaFords.com
Moderator
Member # 655
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posted
quote:
Originally posted by wilit:
This may be a stupid question, but what type of dyno was it tested on? I know Mustang dyno's are notorious for giving underated HP & Torque numbers. Generally 10-15% lower than what you'd get from a Dynojet.
Yeah, those are corrected numbers too right?
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-SLOWER TRAFFIC KEEP RIGHT-
Posts: 5132 | From: Bay Area, CA | Registered: Dec 2001
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93PONY
Mr. Valve Events
Member # 60
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posted
1. Port those headers to match the heads. & check all the openings of the entire exhaust system to make sure they're at least 2.5 inches. The exhaust is the restriction in the combo.
2. To get HP to peak as high as TQ, retard the cam 6 degrees from where it is now. I don't care what it's in on...just move the fucker.
3. Get rid of the cold-air in favor of a minimal bend pipe....make something, you're good with poles & pipes I hear. ![[Eek!]](eek.gif)
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www.advancedenginedevelopment.com
SCT dealer
Dynotuning
(916)715-7569
Posts: 4265 | From: Fair Oaks, CA | Registered: Nov 2000
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Jeff S
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Member # 371
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posted
It was a Dynojet dyno. The numbers are SAE. I'm not sure if the cam was degreed as the shop the built the shortblock installed it. The injectors are 42's but it has DFI and the AF ratio was 13:1 across the board.
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'90 Mustang LX: 8.53 @ 157.92 w/ 1.33 60' on DR's
'10 ZR1: FOR SALE
'14 E63 S: RENNtech ECU
'04 Gallardo: UGR TTG
Posts: 2121 | From: San Jose, CA | Registered: Aug 2001
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mtbaughs
Road Racer
Member # 4052
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posted
We are sure that this is a 10.5:1 motor? I would say it should easily pull well over 300 horsepower to the wheels. The only thing I could think of is that the compression is lower than thought. Are the AFR heads 58cc's? Maybe run a compression check on all eight and see what #'s your getting. I would expect at least 205-210psi from each hole. If there was a goof up and he got a blower compression motor that might explain the low numbers. Even with a tame cam which he doesn't have he should see at least 300+ to the wheels. I've seen a 302 with an e cam run closer to 300 horsepower.
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R.I.P. Charlie Bruno Dec 2001
Posts: 2019 | From: Boise, Idaho | Registered: Jan 2004
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Jeff S
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Member # 371
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posted
It definitely is 10.5:1 I've seen the pistons myself and they are flatops.
We are going to do a leakdown and compression check, but the car doesn't act up or puff any smoke. I'm thinking maybe the valves are adjusted incorrectly preventing them from fully closing...
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'90 Mustang LX: 8.53 @ 157.92 w/ 1.33 60' on DR's
'10 ZR1: FOR SALE
'14 E63 S: RENNtech ECU
'04 Gallardo: UGR TTG
Posts: 2121 | From: San Jose, CA | Registered: Aug 2001
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93PONY
Mr. Valve Events
Member # 60
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posted
quote:
Originally posted by Jeff S:
I'm thinking maybe the valves are adjusted incorrectly preventing them from fully closing...
Very possible!
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www.advancedenginedevelopment.com
SCT dealer
Dynotuning
(916)715-7569
Posts: 4265 | From: Fair Oaks, CA | Registered: Nov 2000
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mtbaughs
Road Racer
Member # 4052
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posted
Yes it could be that as well.
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R.I.P. Charlie Bruno Dec 2001
Posts: 2019 | From: Boise, Idaho | Registered: Jan 2004
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chosen1
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Member # 1906
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posted
robs cousin built a car for a customer with basically that same exact setup.
it made 270 rear wheel.
Posts: 2205 | Registered: Sep 2002
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66 AC COBRA
Nitrous King
Member # 904
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posted
is this through an auto
if its is the converter might be off on stall
i would also check the valves, my money is on the valves not closing all the way
also very stupid but make sure he doesnt have 2 spark plug wires crossed, that would definetly casue the problem
and if the crossed wire isnt on #1, then the timing wont be off
i am still gonna say valve adjustment problem
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FFR AC Cobra
72 Vega - WCHRA Extreme 10.5
Posts: 6280 | From: Winters | Registered: Feb 2002
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season'd 88
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Member # 169
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posted
Hey Jeff, mine is almost identical to this except a 342. Mine made 365rwhp and 380tq. Its got 30lb injectors and 'at the time it had 70mm tb and 70mm maf and a factory airbox. Sounds way off the mark.
Posts: 1383 | Registered: Feb 2001
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1SLOWLX
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Member # 558
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posted
wow something is wrong with that
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Built Tuff with your stuff ;)
Posts: 5231 | From: bay area | Registered: Nov 2001
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Glenn
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Member # 520
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posted
jeff my car made the same exact #'s, but my combo was a lot smaller. I was running AFR 165's, a 306, 9.2:1 compression, & the same cam. there is definetly something wrong with your friends car.
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S-Trim,331,H/C/I
"JohnB groupie train"
My Car
DragGuam
Posts: 2009 | From: Stationed on a Pacific Island, Guam | Registered: Oct 2001
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Blue Oval
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Member # 2548
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posted
im gonna put my money on the valve adjustment.id cant think of any thing else thats likely.good luck
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65 Coupe 306, AFR's
89 Cali. Ed. Saleen "sold"
BAB 89 GT
08 Yamaha R6
Posts: 2345 | From: Sacramento | Registered: Mar 2003
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