low power with patriot heads?
03-29-2004, 09:18 AM
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low power with patriot heads? My bud has a 98 vette, auto 3300, 3.42, halltech.
It dyno'ed 305ish before convertor I believe.
We put on patriot 5.7 stage II milled, ls6 intake, asp pulley, comp cam 224/224 .581/.581 114 lsa, and kook longtubes.
We dynoed that night, and it made 375 untuned. My other bud had forgot to plug in a wire near starter, and it made car run VERY VERY lean. like 18:1, probably leaner but it wouldn't even register. We put a maft on it, and it then made 372 but we got out of it because it still wasn't right.
We then tuned a few days later, and got the a/f to be rock solid, 12.9-13.1. The car only made 360ish.
Could there be a bad seat or something in the head that after driving for a while and getting miles on it is causing it to leak and not hold/make power? We are confused, the car should make more power than this.
It has 80k miles, stock cat back, and no ported tb. But 360 is still a bit low, we feel.
Thoughts?
It dyno'ed 305ish before convertor I believe.
We put on patriot 5.7 stage II milled, ls6 intake, asp pulley, comp cam 224/224 .581/.581 114 lsa, and kook longtubes.
We dynoed that night, and it made 375 untuned. My other bud had forgot to plug in a wire near starter, and it made car run VERY VERY lean. like 18:1, probably leaner but it wouldn't even register. We put a maft on it, and it then made 372 but we got out of it because it still wasn't right.
We then tuned a few days later, and got the a/f to be rock solid, 12.9-13.1. The car only made 360ish.
Could there be a bad seat or something in the head that after driving for a while and getting miles on it is causing it to leak and not hold/make power? We are confused, the car should make more power than this.
It has 80k miles, stock cat back, and no ported tb. But 360 is still a bit low, we feel.
Thoughts?
03-29-2004, 09:25 AM
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Originally Posted by Greg Fell
My bud has a 98 vette, auto 3300, 3.42, halltech.
It dyno'ed 305ish before convertor I believe.
We put on patriot 5.7 stage II milled, ls6 intake, asp pulley, comp cam 224/224 .581/.581 114 lsa, and kook longtubes.
We dynoed that night, and it made 375 untuned. My other bud had forgot to plug in a wire near starter, and it made car run VERY VERY lean. like 18:1, probably leaner but it wouldn't even register. We put a maft on it, and it then made 372 but we got out of it because it still wasn't right.
We then tuned a few days later, and got the a/f to be rock solid, 12.9-13.1. The car only made 360ish.
Could there be a bad seat or something in the head that after driving for a while and getting miles on it is causing it to leak and not hold/make power? We are confused, the car should make more power than this.
It has 80k miles, stock cat back, and no ported tb. But 360 is still a bit low, we feel.
Thoughts?
It dyno'ed 305ish before convertor I believe.
We put on patriot 5.7 stage II milled, ls6 intake, asp pulley, comp cam 224/224 .581/.581 114 lsa, and kook longtubes.
We dynoed that night, and it made 375 untuned. My other bud had forgot to plug in a wire near starter, and it made car run VERY VERY lean. like 18:1, probably leaner but it wouldn't even register. We put a maft on it, and it then made 372 but we got out of it because it still wasn't right.
We then tuned a few days later, and got the a/f to be rock solid, 12.9-13.1. The car only made 360ish.
Could there be a bad seat or something in the head that after driving for a while and getting miles on it is causing it to leak and not hold/make power? We are confused, the car should make more power than this.
It has 80k miles, stock cat back, and no ported tb. But 360 is still a bit low, we feel.
Thoughts?
03-29-2004, 09:42 AM
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hmm 55rwhp from Heads, Cam, LTs, Intake & a Pulley! Wow, thought my car was an underdog, but I havent done heads yet. Who is tuning, wheres the timing at, and does the graph show it dropping right off, what rpm? Need the graph! There seems to be something, but could be tune, not enough rpm, or parts installed.
Good luck
Charlie
Good luck
Charlie
03-29-2004, 09:48 AM
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doesnt sound like a PP head problem to me, sounds like you either screwed something up going 18:1 or the tuning is off somehow. I would dig deeper before passing blame. Also a stock catback...your kidding right?
03-29-2004, 10:06 AM
#5
the numbers are a bit low but remember you probably lost 10-15hp with the new vert so in all it looks like you gained 75hp with your mods...im not saying its great maybe 10-20hp off of probably what it should be...wheres your timing set at?
lata
Bill
lata
Bill
03-29-2004, 10:28 AM
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Originally Posted by gomer
Hmm... maybe you hurt something running it at over 18:1?? Can you post up a graph of the latest run, along with the A/F. Also, does the car still have cats on it?
BTW 375 untuned with a stall, stock T-body, stock catback and vette IRS isn't bad at all.
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03-29-2004, 11:16 AM
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I'm thinking more along the lines of a burnt plug or cracked piston/ringland. 18:1 (actually higher than that) is not a good thing. The number 8 header tube was glowing red. We are going to pull the plugs and do a leak down test.
The car is tuned now. it has a very steady 12.9-13.1 afr across board. We are running about 26 degrees max timing, as he sprays a 100 shot on it.
The car is tuned now. it has a very steady 12.9-13.1 afr across board. We are running about 26 degrees max timing, as he sprays a 100 shot on it.
03-29-2004, 03:05 PM
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Yeah but while tunning one should not just retard 2+ degrees advance just as a rule of thumb. Car should be autotaped on the run, while monitoring AFR and using progressive shots of N20. DETONATION HAS TO BE AVOIDED. But that doen't mean you can't fine tune it to get the most out of it.
A whole bunch of windows can be used with knock guages to adjust at the track if atmospheric conditions change.
Let me put it this way, I shoot 140rwhp dry on a stock tune/cam with TR6's and still no knock, I even extanded my shifting point from 2-3 to 6000 to make use of the extra timming.
A whole bunch of windows can be used with knock guages to adjust at the track if atmospheric conditions change.
Let me put it this way, I shoot 140rwhp dry on a stock tune/cam with TR6's and still no knock, I even extanded my shifting point from 2-3 to 6000 to make use of the extra timming.
03-29-2004, 04:00 PM
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Where do you get 140jets from? Oh you mean 150 jets but you only get 140 right? And dont forget what works for you may not work for someone else. Hell I ran 150jets on 33* timing from predator diablosport, no KR at all. I also tried it on 180NXL jets, but went with a fatter AFR than 13.1, mine was more like 12.4 or so, and used some Race gas mixed in.
I havent seen a primary glow from excess timing, but definatley from running lean as ****. Which run it lean enough and you may not see any KR. Waiting to see.
Charlie
I havent seen a primary glow from excess timing, but definatley from running lean as ****. Which run it lean enough and you may not see any KR. Waiting to see.
Charlie
03-30-2004, 08:25 AM
#17
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Well the 140# is a ballpark. i'm running 5177 with no jets. If such heavy detonation occurred, to the point that the header primary was glowing, believe me that your knock sensors will pick it up.
Also let us not forget the old school and read our plugs. Speckels means detonation. Did u even remove and check ur plugs after the 18:1 thing. I think some of them could be melted.
One thing I forgot to mention is that premium gas here is 98 octane. That helps a bit.
Also let us not forget the old school and read our plugs. Speckels means detonation. Did u even remove and check ur plugs after the 18:1 thing. I think some of them could be melted.
One thing I forgot to mention is that premium gas here is 98 octane. That helps a bit.
Last edited by PREDATOR-Z; 03-30-2004 at 01:30 PM. Reason: update
03-30-2004, 10:08 AM
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ok, dual leakdown tests 1-168 / 3-167 / 5-169 / 7-169 ; 2-168 / 4-160 / 6-162 / 8-164
here are dyno runs...
http://the-josephs.com/gfell/jeff_heads.pdf
http://the-josephs.com/gfell/jeff_heads_nitrous.pdf
Still has stock vette cats/catback, and no ported tb.
here are dyno runs...
http://the-josephs.com/gfell/jeff_heads.pdf
http://the-josephs.com/gfell/jeff_heads_nitrous.pdf
Still has stock vette cats/catback, and no ported tb.
03-30-2004, 12:10 PM
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This is my ride; would it be feasible for this car to gain ~30HP from ditching the cats and/or upgrading from the stock exhaust? User's chime in, I'm interested to hear your thoughts.
I want to get ~390. My 'tuned' dyno came out to ~360, well below where i was expecting. I had not expected to be 30 rwhp short of my goal by simply not having an efficient cat-back. I want to maintain some sort of 'sleeper' appeal to this car, yet i can't feel right leaving a whopping 30hp+ on the table. Right now it sounds quite perfect. Besides any other comments you may have, does anyone have some good, first-handed insight on a rather stealthy cat-back exhaust?
I want to get ~390. My 'tuned' dyno came out to ~360, well below where i was expecting. I had not expected to be 30 rwhp short of my goal by simply not having an efficient cat-back. I want to maintain some sort of 'sleeper' appeal to this car, yet i can't feel right leaving a whopping 30hp+ on the table. Right now it sounds quite perfect. Besides any other comments you may have, does anyone have some good, first-handed insight on a rather stealthy cat-back exhaust?
03-30-2004, 12:21 PM
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Hi Jeff
That cobra is going to want a rematch!
Why don't you just go with some electric cutouts and still have the quiet exhaust you want. I would try taking off the cat back and doing a run and see if that is what is eating HP before spending money on a new one.
Later
Jim
That cobra is going to want a rematch!
Why don't you just go with some electric cutouts and still have the quiet exhaust you want. I would try taking off the cat back and doing a run and see if that is what is eating HP before spending money on a new one.
Later
Jim