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Author
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Topic: Baseline Dyno Numbers -> Stock 96 Cobra
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Luke87GT
Lay'n more stripes
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Member # 21
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posted
 
 
Hi folks,
I was finally able to get some baseline dyno numbers on my 96 Cobra this weekend. Before I go any further, the only mods worth mentioning at this point are the FMS aluminum driveshaft and the FMS 4.30 gears. I don’t think there is anything else on the car currently that would influence power figures in any significant way.
Some additional information… The spark plugs and wires have about 15K miles and the fuel filter is brand new. With 89 octane in the tank and 82deg air temperature, the car laid down 271.13rwhp@5750rpm & 263.64rwtq@4550rpm uncorrected, however, all the numbers below are shown as SAE corrected with “level-5” smoothing. We performed four baselines runs with approximately 10-15 minutes of cool down between each pull with a large fan blowing over the motor.
The A/F was measured out the tailpipe. Since I am still running stock cats, and since the measurements were taken far downstream of the motor, I was told by the tuner that the meter would read leaner than it really is.
Run #1
The car laid down 261rwhp/253rwtq SAE, however, there were two small dips within the power curve that were each briefly responsible for about ~10rwhp loss looking at the peak-to-peak results. After studying the OBDII log parameters, I discovered that the only data log that stood out was the spark advance, which is shown above. The dips in power seem to roughly coincide with the dips in the spark (am I correct to assume that this data-log parameter is simply the timing? In other words the motor was briefly pulling timing during this run? If so, what could potentially cause that?). You can see that the spark is at about 25 degrees and then drops down to 18 degrees.
Run #2
The car laid down 268rwhp/261rwtq SAE. Once again, the dips in power coincide with the dips in spark advance… 27deg down to 18 degrees this time.
Run #3
The car laid down 256rwhp/264rwtq SAE. As you can see, at about 4700rpm, the spark dropped from 27deg down to 18deg and stayed flat all the way through the pull resulting in about 12rwhp short of the previous pull!
In order to isolate the spark from the IMRC plates, we decided to do one more pull and monitor the voltage output of the IMRCs to ensure that they are staying open at high RPM.
Run #4
The car laid down 267rwhp/270rwtq SAE this time. As you can see from the graph, the car made peak HP during a short pulse transition where the spark jumped from 18deg to 25deg briefly. The IMRC show to be opening at 3600rpm and don’t look to be influencing anything negatively.
One conclusion is that the car seems to be running far too rich according to the A/F data. Also, the remaining question I have now is what could be influencing the spark to drop from 25-27deg to 17-18deg at high RPM (this looks to be costing me ~10rwhp). It was certainly a warm day, and the car did not have much time to cool. The 89 octane probably didn’t help either.
Also, I will do my research, but if anyone could shed some light on more information about the “Spark” data log parameter, what exactly it is, and what influences it, I’d appreciate it! The following items were logged in case any of them may give us an additional clue (I'd be happy to post any available data here):
Next time I dyno, the car will have new ignition coils, 91 octane in the tank, JLT intake, exhaust, pulleys, IMRC deletes and a short runner…
The tuner recommended that I check the plugs, the resistance of the plug wires, and consider replacing the stock coils before I go in for a dyno tune.
I look forward to your feedback! ![[patriot]](graemlins/patriot.gif)
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Stangless
Posts: 7802 | From: San Mateo | Registered: Jul 2000
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Luke87GT
Lay'n more stripes
than Caltrans
Member # 21
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posted
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Stangless
Posts: 7802 | From: San Mateo | Registered: Jul 2000
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*EPIK*
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Member # 7481
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posted
Not bad numbers at all Luke. seems to be right on par with what they should normally be given the 305hp rating. 1 question, why are you running 89 octane instead of 91 octane?
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=91 Notch:12.31@110 **Under Construction**
=05 CTS-V: 418rwhp/393rwtq=13.01@111
http://www.djepikmusic.com
Posts: 6966 | From: 916 | Registered: Mar 2007
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Luke87GT
Lay'n more stripes
than Caltrans
Member # 21
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posted
Thanks Dustin.
I actually didn't think much of it as the car is bone stock and it is just what I happen to have in there. Looking at the big picture, between the combination of it being hot out (82deg) with limited cool down time, maybe the higher octane would have prevented the spark from jumping around like it did?
89 was probably a mistake on my part...
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Stangless
Posts: 7802 | From: San Mateo | Registered: Jul 2000
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SydeWaySix
CAFords OG
Member # 3596
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posted
with the mods that you are doing before your next dyno session, what do you expect to make? I'm trying to see what I can do to make 300rwhp without any major mods and still be smog legal. Are you going to run LT's and off-road x/h-pipe?
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2013 Boss 302 #356. Performance White. Stock.
1965 Fastback GT Restored to stock spec.
Posts: 9882 | From: Bay Area | Registered: Dec 2002
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Mr.Lucky
CAFords OG
Member # 1772
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posted
Nice numbers. Is that Nextgen other shop off winton?
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95GT: Bolt ons.
Good sellers/buyers: Stangs R Us, 1SicGt, sn4bwc, racsirx, WickedStang, Autumnstang97, cali95gt
Posts: 4197 | From: Manteca | Registered: Sep 2002
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Blind
2.3L
CAFords OG
Member # 3052
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posted
I think the computer was pulling timing because of the knock sensors and the 89 octane, I always run 91 in my 4v, I thought that was the requirement even stock?
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89 LX Notchback ex 4cyl, 14psi
02 Harley F150, 15psi
Posts: 8521 | From: Fairfield | Registered: Jul 2003
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stangin'
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Member # 514
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posted
91 octane is roughly about $1-2 more per fill-up. don't skimp on good gas with these motors. it probably did have something to do with the dips.
just for kicks, my old '97 cobra dynoed at 286 rwhp. this was with an o/r x-pipe, cai, pulleys, and catback.
Posts: 2993 | From: Bay Area | Registered: Oct 2001
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Luke87GT
Lay'n more stripes
than Caltrans
Member # 21
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posted
Thanks guys!
quote:
Originally posted by SydeWaySix:
with the mods that you are doing before your next dyno session, what do you expect to make? I'm trying to see what I can do to make 300rwhp without any major mods and still be smog legal. Are you going to run LT's and off-road x/h-pipe?
I don't have any firm expectations at this point. I'll try to address the reason why the timing was being pulled and throw the planned mods at it and reaccess...
I will not be running long-tubes, and I have not yet decided on exactly which midpipe will go on but it will have stock manifolds and 2.5" exhaust the rest of the way (straight through mufflers)...
quote:
Originally posted by bottled95GT??:
Nice numbers. Is that Nextgen other shop off winton?
Thanks, yes it is.
quote:
Originally posted by Blind:
I think the computer was pulling timing because of the knock sensors and the 89 octane, I always run 91 in my 4v, I thought that was the requirement even stock?
You might be right Kevin. I should have used 91 octane. If it is detonation, it's puzzling that the A/F ratio was so rich at high RPM. I am sure that 91 octane, 180* stat, and cooler weather would have a positive effect on the timing retard...
quote:
Originally posted by stangin':
just for kicks, my old '97 cobra dynoed at 286 rwhp. this was with an o/r x-pipe, cai, pulleys, and catback.
Nice numbers. If my Cobra lays those numbers before the IMRC deletes/Short runner/Tune, I'd be thrilled...
Cheers!
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Stangless
Posts: 7802 | From: San Mateo | Registered: Jul 2000
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CobraChick
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Member # 9885
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posted
I'm not sure about the older cobra but our 03 cobras says in the manual and on the cluster to use premium fuel. So thats the only thing we put in the car is 91 octane shell or chevron gas only. But like i said might be different with the older one i would look in the manual
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Behind ever successful person is a pack of haters.
Posts: 675 | Registered: Mar 2010
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Blind
2.3L
CAFords OG
Member # 3052
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posted
quote:
Originally posted by Luke87GT:
quote:
Originally posted by Blind:
I think the computer was pulling timing because of the knock sensors and the 89 octane, I always run 91 in my 4v, I thought that was the requirement even stock?
You might be right Kevin. I should have used 91 octane. If it is detonation, it's puzzling that the A/F ratio was so rich at high RPM. I am sure that 91 octane, 180* stat, and cooler weather would have a positive effect on the timing retard...
unburned fuel will show as rich at the pipes, so it makes sense for the A/F to appear rich but the engine itself is actually running lean - hook up an SCT and watch the short term fuel trims for each bank during a WOT run to see what the computer is actually doing, when it see's detonation AFAIK it pulls timing and adds fuel.
my fobra made 282rwhp/278rwtq with IMRC delete's, stock mid pipe, BBK fenderwell filter, stock GT MAF, and the dynomax catback, it had an intake manifold vacuum leak from a torn EGR gasket during that, and that's with lincoln cams that everybody says are crap, but I love because the torque curve is just flat ![[Smile]](smile.gif)
I'm looking forward to the next time I dyno it, where I'll be re-tuning it for a lightning MAF, have a new 2.5" midpipe, and fixed the intake manifold leak so the fuel trims don't freak out all over the place now. I'd like to do a short runner also, just hesitant to mess it up, I need to pick up a spare intake to do it to...
[ June 07, 2010, 09:25 PM: Message edited by: Blind ]
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89 LX Notchback ex 4cyl, 14psi
02 Harley F150, 15psi
Posts: 8521 | From: Fairfield | Registered: Jul 2003
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96mysticman
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Member # 8327
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posted
my 96 cobra that i used to have put down 276rwhp/276tq completly bone stock minus an off road xpipe. also it was 98 degrees outside.
maybe if you put the recomended octane in there you might pick up some hp. just my .02
Posts: 580 | From: stockton | Registered: Apr 2008
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rozwell911
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Member # 9917
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posted
Luke, are you planning on getting a base tune done when you get the IMRC deletes?
its my understanding that the IMRC delets, when the car is not tuned for them, will cause a loss in low-end torque.
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2007 GT Vista Blue
-Hurst Short Shifter
-Bassani X-pipe
-Bassani Axle Back
-MAC RAI
-AED Tuned 296.7 RWHP and 333.8 RWTQ
Posts: 33 | From: San Jose | Registered: Apr 2010
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Luke87GT
Lay'n more stripes
than Caltrans
Member # 21
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posted
Blind and 96mysticman, those are impressive numbers! What were those figures that you posted? Uncorrected? STD? SAE? And was this untuned? I'm finding that most 96-98 Cobras lay down between 260-270rwhp SAE on a dynojet, stock (There is a lengthy post about this on svtperformance).
It's sometimes frustrating to compare results when people don't specify those figures or even know what they are, lol. If I choose the correct correction and avoid using the smooth function, my numbers are showing 276rwhp.
My preference is that Dynojet would only post SAE to force people to establish a common ground, lol.
[ June 08, 2010, 02:06 PM: Message edited by: Luke87GT ]
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Stangless
Posts: 7802 | From: San Mateo | Registered: Jul 2000
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Blind
2.3L
CAFords OG
Member # 3052
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posted
superflow SAE corrected/dynojet comparison #'s, loaded dyno, I didn't get a print out of the raw #'s, but they're not all that different.
my `89 with stock motor 5.0 but all the bolt-on's/no p/s, no smog pump, electric fan, shorty header full exhaust, etc. made 249rwhp/295rwtq on the same dyno, right inline with my buddy coupester/Christian from the corral that made 245rwhp/298rwtq with his bolt on stock motor 5.0 that had longtube exhaust.
[ June 08, 2010, 02:08 PM: Message edited by: Blind ]
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89 LX Notchback ex 4cyl, 14psi
02 Harley F150, 15psi
Posts: 8521 | From: Fairfield | Registered: Jul 2003
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SydeWaySix
CAFords OG
Member # 3596
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posted
So how does a Dynojet's numbers compare to a Mustang Dyno's (I think these are the ones where you set the load)?
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2013 Boss 302 #356. Performance White. Stock.
1965 Fastback GT Restored to stock spec.
Posts: 9882 | From: Bay Area | Registered: Dec 2002
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Blind
2.3L
CAFords OG
Member # 3052
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posted
quote:
Originally posted by SydeWaySix:
So how does a Dynojet's numbers compare to a Mustang Dyno's (I think these are the ones where you set the load)?
mustang dyno's have really high #'s from what I've seen
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89 LX Notchback ex 4cyl, 14psi
02 Harley F150, 15psi
Posts: 8521 | From: Fairfield | Registered: Jul 2003
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Luke87GT
Lay'n more stripes
than Caltrans
Member # 21
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posted
quote:
Originally posted by Blind:
quote:
Originally posted by SydeWaySix:
So how does a Dynojet's numbers compare to a Mustang Dyno's (I think these are the ones where you set the load)?
mustang dyno's have really high #'s from what I've seen
Opposite, Mustang Dyno's typically read 5% low
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Stangless
Posts: 7802 | From: San Mateo | Registered: Jul 2000
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Luke87GT
Lay'n more stripes
than Caltrans
Member # 21
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posted
And Blind, you own the highest stock dyno numbers I have ever seen in my life for both a stock 96-98 Cobra and a stock motored 87-93 Mustang with bolt-ons, lol.
![[worship]](graemlins/worship.gif)
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Stangless
Posts: 7802 | From: San Mateo | Registered: Jul 2000
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SydeWaySix
CAFords OG
Member # 3596
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posted
quote:
Originally posted by Luke87GT:
quote:
Originally posted by Blind:
quote:
Originally posted by SydeWaySix:
So how does a Dynojet's numbers compare to a Mustang Dyno's (I think these are the ones where you set the load)?
mustang dyno's have really high #'s from what I've seen
Opposite, Mustang Dyno's typically read 5% low
Yea, from what I understand they are "more accurate" since they add load to the dyno to resemble the car on the road.
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2013 Boss 302 #356. Performance White. Stock.
1965 Fastback GT Restored to stock spec.
Posts: 9882 | From: Bay Area | Registered: Dec 2002
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Blind
2.3L
CAFords OG
Member # 3052
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posted
quote:
Originally posted by SydeWaySix:
quote:
Originally posted by Luke87GT:
quote:
Originally posted by Blind:
quote:
Originally posted by SydeWaySix:
So how does a Dynojet's numbers compare to a Mustang Dyno's (I think these are the ones where you set the load)?
mustang dyno's have really high #'s from what I've seen
Opposite, Mustang Dyno's typically read 5% low
Yea, from what I understand they are "more accurate" since they add load to the dyno to resemble the car on the road.
a lot of dyno's add load
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89 LX Notchback ex 4cyl, 14psi
02 Harley F150, 15psi
Posts: 8521 | From: Fairfield | Registered: Jul 2003
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Luke87GT
Lay'n more stripes
than Caltrans
Member # 21
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posted
quote:
Originally posted by Blind:
quote:
Originally posted by SydeWaySix:
quote:
Originally posted by Luke87GT:
quote:
Originally posted by Blind:
quote:
Originally posted by SydeWaySix:
So how does a Dynojet's numbers compare to a Mustang Dyno's (I think these are the ones where you set the load)?
mustang dyno's have really high #'s from what I've seen
Opposite, Mustang Dyno's typically read 5% low
Yea, from what I understand they are "more accurate" since they add load to the dyno to resemble the car on the road.
a lot of dyno's add load
Ya, I believe most dynos are loaded dynos. Otherwise the pulls would not take as long as they do.
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Stangless
Posts: 7802 | From: San Mateo | Registered: Jul 2000
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96mysticman
¯
Member # 8327
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posted
quote:
Originally posted by Luke87GT:
Blind and 96mysticman, those are impressive numbers! What were those figures that you posted? Uncorrected? STD? SAE? And was this untuned? I'm finding that most 96-98 Cobras lay down between 260-270rwhp SAE on a dynojet, stock (There is a lengthy post about this on svtperformance).
It's sometimes frustrating to compare results when people don't specify those figures or even know what they are, lol. If I choose the correct correction and avoid using the smooth function, my numbers are showing 276rwhp.
My preference is that Dynojet would only post SAE to force people to establish a common ground, lol.
yeah it was on a dynojet and those are uncorrected numbers. but imo i wouldnt do the imrc deletes mod motors already lack the low end torque why make it any worse? its actually all about what you wanna do? you can either leave the line like an animal with torque or you can be a beast on the top side with the hp.lol have fun ![[Wink]](wink.gif)
Posts: 580 | From: stockton | Registered: Apr 2008
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Luke87GT
Lay'n more stripes
than Caltrans
Member # 21
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posted
The IMRCs cost a few HP below 5K RPM, but it's not anything that can be felt with 4.30s, from what I gather. Above 5K, there is a few HP to be had. It's not the power gains that I am after so much as just not having the butterfly valves in place and risk having them get gunked up or having the IMRC motor stick. Just one less thing to worry about. Since I am going to tune anyway, I don't care about the CEL as it will be eliminated.
Remind me what mods you have to go 114mph (and what uncorrected power level?)
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Stangless
Posts: 7802 | From: San Mateo | Registered: Jul 2000
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