Dyno results of JPR S1's
01-09-2002, 09:54 PM
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Dyno results of JPR S1's Had a very positive first ever dyno today... my little 218 and stage 1 heads put down 401.5 rwhp and 378.9 rwtorque, SAE corrected. The torque is a little low due to the fact I have straight pipes <img src="gr_images/icons/wink.gif" border="0"> so I have to put some cats on to get some backpressure. It holds a high average of torque across the RPM band which is sweet. There is a lot more room for improvement with some tuning and tweaks... tuning was all over the place across the wideband, rich to lean and back again so needs some brushing up. The Larocca's guy was impressed with the results, knowing that the dyno at their shop normally is a bit pessimistic so I was happy!
I am not too obsessive over dyno numbers, I want to see results at the track... but we found out where I need some tweaks and tuning and Mr. Tomcat is turning into a monster. I am totally STOKED about this setup, looks like we are really going to fly. Joe did an excellent job!!! Thanks Joe!
I am not too obsessive over dyno numbers, I want to see results at the track... but we found out where I need some tweaks and tuning and Mr. Tomcat is turning into a monster. I am totally STOKED about this setup, looks like we are really going to fly. Joe did an excellent job!!! Thanks Joe!
01-09-2002, 10:09 PM
#3
Re: Dyno results of JPR S1's Very good numbers for a 1st pull and no tuning
I had a setup like this from Joe too
On my automatic car but i had macs instead of LT's.
Take 4% off your numbers becasue of my auto and u come up with 384RWHP which is realy close to what I dynoed 379RWHP for my S1 setup..
Again Erin GREAT NUMBERS
I bet u see another 5RW from tuning
Who's tuning the car?
Larrocca's?
Good luck
JS
I had a setup like this from Joe too
On my automatic car but i had macs instead of LT's.
Take 4% off your numbers becasue of my auto and u come up with 384RWHP which is realy close to what I dynoed 379RWHP for my S1 setup..
Again Erin GREAT NUMBERS
I bet u see another 5RW from tuning
Who's tuning the car?
Larrocca's?
Good luck
JS
01-09-2002, 10:17 PM
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Re: Dyno results of JPR S1's Your right about track #'s being more important than the dyno #'s. Too many people get caught up in dyno racing rather than real racing out at the track. Anyways, AWESOME #'s <img src="gr_eek2.gif" border="0"> !!!
Good luck at the track,
Mike
Good luck at the track,
Mike
01-09-2002, 10:23 PM
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Re: Dyno results of JPR S1's Great numbers! Have fun with it. <img src="graemlins/burnout.gif" border="0" alt="[Burnout]" />
[ January 09, 2002: Message edited by: 9T9BlueTA ]</p>
[ January 09, 2002: Message edited by: 9T9BlueTA ]</p>
01-09-2002, 11:18 PM
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Re: Dyno results of JPR S1's [quote]Originally posted by ChrisB:
<strong>dyno numbers look great!
I am curious as to why you think backpressure will boost your peak torque though?
Chris</strong><hr></blockquote>
It's a common fact that if u either go with too big of a set of headers/exhaust system or take cats out... u will lose back pressure and therefore lose torque.
<strong>dyno numbers look great!
I am curious as to why you think backpressure will boost your peak torque though?
Chris</strong><hr></blockquote>
It's a common fact that if u either go with too big of a set of headers/exhaust system or take cats out... u will lose back pressure and therefore lose torque.
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01-09-2002, 11:20 PM
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Re: Dyno results of JPR S1's Thanks all <img src="gr_stretch.gif" border="0"> I am very happy <img src="gr_grin.gif" border="0">
As far as backpressure, it was just an idea someone brought up and was generally agreed upon that it could be affecting my torque a bit. So we will see, I will get some cats on the car and eventually redyno and post the results, positive or negative. I recently saw someone here post results from dynoing with and without cats with the 218 comp cam and they gained a decent amount of power when the cats were put on the car vs ORP's. So just an idea, aside from the tuning issues, still more power there.
As far as backpressure, it was just an idea someone brought up and was generally agreed upon that it could be affecting my torque a bit. So we will see, I will get some cats on the car and eventually redyno and post the results, positive or negative. I recently saw someone here post results from dynoing with and without cats with the 218 comp cam and they gained a decent amount of power when the cats were put on the car vs ORP's. So just an idea, aside from the tuning issues, still more power there.
01-09-2002, 11:53 PM
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Re: Dyno results of JPR S1's Uh, no cats, longtubes, and an open cutout got me 399rwtq, closed the cutout (more backpressure) and got 392rwtq.
Not sure why your torque is lower...figured the JPR stuff was built for torque.
Not sure why your torque is lower...figured the JPR stuff was built for torque.
01-10-2002, 12:59 AM
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Re: Dyno results of JPR S1's [quote]Originally posted by WS6 TransAm Girl:
<strong>Had a very positive first ever dyno today... my little 218 and stage 1 heads put down 401.5 rwhp and 378.9 rwtorque, SAE corrected. The torque is a little low due to the fact I have straight pipes <img src="gr_images/icons/wink.gif" border="0"> so I have to put some cats on to get some backpressure. It holds a high average of torque across the RPM band which is sweet. There is a lot more room for improvement with some tuning and tweaks... tuning was all over the place across the wideband, rich to lean and back again so needs some brushing up. The Larocca's guy was impressed with the results, knowing that the dyno at their shop normally is a bit pessimistic so I was happy!
I am not too obsessive over dyno numbers, I want to see results at the track... but we found out where I need some tweaks and tuning and Mr. Tomcat is turning into a monster. I am totally STOKED about this setup, looks like we are really going to fly. Joe did an excellent job!!! Thanks Joe!</strong><hr></blockquote>
Wow, very good numbers... Could you list all your mods? Is your cam the Comp Cams 212/218?
Also I assume you have an M6?
<strong>Had a very positive first ever dyno today... my little 218 and stage 1 heads put down 401.5 rwhp and 378.9 rwtorque, SAE corrected. The torque is a little low due to the fact I have straight pipes <img src="gr_images/icons/wink.gif" border="0"> so I have to put some cats on to get some backpressure. It holds a high average of torque across the RPM band which is sweet. There is a lot more room for improvement with some tuning and tweaks... tuning was all over the place across the wideband, rich to lean and back again so needs some brushing up. The Larocca's guy was impressed with the results, knowing that the dyno at their shop normally is a bit pessimistic so I was happy!
I am not too obsessive over dyno numbers, I want to see results at the track... but we found out where I need some tweaks and tuning and Mr. Tomcat is turning into a monster. I am totally STOKED about this setup, looks like we are really going to fly. Joe did an excellent job!!! Thanks Joe!</strong><hr></blockquote>
Wow, very good numbers... Could you list all your mods? Is your cam the Comp Cams 212/218?
Also I assume you have an M6?
01-10-2002, 01:56 AM
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Re: Dyno results of JPR S1's If you have a good set of headers and your a/f and spark under control then less back pressure will pick up your torque/horsepower across the board. No question.
If you are still running stock manfolds you *may* loose below your torque peak, but at your torque peak an above you should still gain. At your torque peak your engine is at max VE, working as effeciently as it can. You definitely don't want any back pressure.
Like jMX mentioned there are tons of dynoes of people making better power with open longtubes, etc. Mac's or better and you should be set.
When you do see a dip/problem it is normally caused by bad fuel/spark settings. If you go from a restrictive exhaust to an open header you have just greately improved the quality of your a/f charge. Generally this is going to require more fuel and less spark. If you don't alter it then you very well could be down. But it's not because of lack of backpressure (which is bad), but improper tuning.
Chris
If you are still running stock manfolds you *may* loose below your torque peak, but at your torque peak an above you should still gain. At your torque peak your engine is at max VE, working as effeciently as it can. You definitely don't want any back pressure.
Like jMX mentioned there are tons of dynoes of people making better power with open longtubes, etc. Mac's or better and you should be set.
When you do see a dip/problem it is normally caused by bad fuel/spark settings. If you go from a restrictive exhaust to an open header you have just greately improved the quality of your a/f charge. Generally this is going to require more fuel and less spark. If you don't alter it then you very well could be down. But it's not because of lack of backpressure (which is bad), but improper tuning.
Chris
01-10-2002, 07:57 AM
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Re: Dyno results of JPR S1's There was talk amongst the Mustang guys that were there yesterday about the back pressure idea, I was too busy to working to really lend it any attention, first, these are prelim numbers right off the street without having an A-Tap look, the laptop that we were supposed to use took a crap so we were flying blind on the dyno. My personal feelings about these low numbers after watching the WB is a simple fact that it needs tuning. The WB AF during the dyno pull was showing 3 irratic swings across the RPM band of rich (12.2) to lean (13.9) and back again. I knew on the first pulls I was going to have a real challange getting the FT settled down with just a MAFT so there were adjustments in the base and 4 clicks of WOT to obtain the above mentioned WB AF numbers. I hope to get an edit session or possibly Ed Wright.
01-10-2002, 08:17 AM
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Re: Dyno results of JPR S1's There is definitely more in it! Congrats Erin and Joe!
I think tuning is the key for that setup but I am willing to bet that cats will lower your numbers and not raise them. The backpressure idea is a misconception by many and more backpressure will only hurt you if you have a correct AF and timing curve plus decent headers.
Cheers,
Chris
I think tuning is the key for that setup but I am willing to bet that cats will lower your numbers and not raise them. The backpressure idea is a misconception by many and more backpressure will only hurt you if you have a correct AF and timing curve plus decent headers.
Cheers,
Chris
01-10-2002, 08:31 AM
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Re: Dyno results of JPR S1's Well thanks for the nice words guys <img src="gr_stretch.gif" border="0"> I appreciate it.
JmX- whatever you say. They are impressive numbers <img src="gr_images/icons/wink.gif" border="0"> We'll get that torque up a bit, I'm not too concerned about it. When we get the car tuned in, we will have a better idea of where we stand though.
And you may all be right about the backpressure thing, it was just an idea that was tossed around at the time that seemed like a possibility. Probably more of the problems are resultant of the tuning being off. Anyways, I am very satisfied, and it's nice to know that there is more left in the car.
For everyone who asked, my mods are in my signature.
<img src="graemlins/formula.gif" border="0" alt="[Pontiac]" />
JmX- whatever you say. They are impressive numbers <img src="gr_images/icons/wink.gif" border="0"> We'll get that torque up a bit, I'm not too concerned about it. When we get the car tuned in, we will have a better idea of where we stand though.
And you may all be right about the backpressure thing, it was just an idea that was tossed around at the time that seemed like a possibility. Probably more of the problems are resultant of the tuning being off. Anyways, I am very satisfied, and it's nice to know that there is more left in the car.
For everyone who asked, my mods are in my signature.
<img src="graemlins/formula.gif" border="0" alt="[Pontiac]" />
01-10-2002, 08:38 AM
#17
Re: Dyno results of JPR S1's Back pressure is BS. Its all about exhaust gas velocity and scavenging. If your average torque across the power band was increased by back pressure, you would see everyone running 1" header tubes.
Nice results on the heads. <img src="gr_stretch.gif" border="0">
I have a very low mileage set of Joe's S-1x and TR 224 cam available for sale for anybody looking for a set.
Nice results on the heads. <img src="gr_stretch.gif" border="0">
I have a very low mileage set of Joe's S-1x and TR 224 cam available for sale for anybody looking for a set.
01-10-2002, 10:14 AM
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Re: Dyno results of JPR S1's Congrats that setup looks like it will be a good sleeper car. Has the computer been tuned? I have a friend with that cam and locally ported heads. He took his car to Ed and picked up 18hp and 26tq peak. The car actually made almost 35ft/lbs more at 3,500-4,500.
