Need your help with FLAT HP curve.
12-08-2001, 08:55 AM
#1
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Need your help with FLAT HP curve. Here is a reprint of my post from below. I need your ideas fellas. I am going to try and throw on my offroad Ypipe today to see if that helps.
Thanks,
Chris
My car has been feeling a little flat up top lately.
Here are my mods:
ARE 360 with S1 blower ported heads and 221/221 114LSA 558 lift cam
Yank 4L70 tranny
12 bolt with spool 4.11s
dual 3inch carsound cats in MAC Ypipe with a 3inch extension and bullet muffler under the axle.
Dynoed today and my horsepower curve with the converter locked is almost straight across from 5000rpm and up. (spiked at 365RWHP and 404RWTQ)
I lost 2mph when I put the cats on the car (118mph to 116mph) (Best ET 11.70116.5mph with a half throttle 1.67 sixty in first with cats on the car)
I am wondering if they could be clogged up or would I have another issue. The cam should be peaking around 6400rpm not 5000 and holding it straight across <img src="images/icons/frown.gif" border="0">
Any ideas?
Thanks,
Chris
ps- My converter was flashing to 4800rpm on the dyno!!
Thanks,
Chris
My car has been feeling a little flat up top lately.
Here are my mods:
ARE 360 with S1 blower ported heads and 221/221 114LSA 558 lift cam
Yank 4L70 tranny
12 bolt with spool 4.11s
dual 3inch carsound cats in MAC Ypipe with a 3inch extension and bullet muffler under the axle.
Dynoed today and my horsepower curve with the converter locked is almost straight across from 5000rpm and up. (spiked at 365RWHP and 404RWTQ)
I lost 2mph when I put the cats on the car (118mph to 116mph) (Best ET 11.70116.5mph with a half throttle 1.67 sixty in first with cats on the car)
I am wondering if they could be clogged up or would I have another issue. The cam should be peaking around 6400rpm not 5000 and holding it straight across <img src="images/icons/frown.gif" border="0">
Any ideas?
Thanks,
Chris
ps- My converter was flashing to 4800rpm on the dyno!!
12-08-2001, 09:15 AM
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Re: Need your help with FLAT HP curve. Chris,
Was 365 RWH your max, was that about the same as when you pulled the 11.70?
<img src="images/icons/confused.gif" border="0">
Was 365 RWH your max, was that about the same as when you pulled the 11.70?
<img src="images/icons/confused.gif" border="0">
12-08-2001, 11:42 AM
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Re: Need your help with FLAT HP curve. Yep the 11.70 run was through the cats with the car feeling a little flat up top. The launch and traction was terrible for that run too (1.67 sixty with half throttle in first)
The car has 11.40s as it sits now but I want to get back the 20 HP I lost and my curve looking normal again.
Chris
The car has 11.40s as it sits now but I want to get back the 20 HP I lost and my curve looking normal again.
Chris
12-08-2001, 04:23 PM
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Re: Need your help with FLAT HP curve. Well I put on the offroad Ypipe and hooked ATAP up to the car <img src="images/icons/smile.gif" border="0">
well the hard starting (cranking for a while before starting) is totally gone. Fires up right away now <img src="images/icons/grin.gif" border="0">
My LTRIMS are in the -6 range on one bank and the -2.x range on the other. I thought that was odd. I am running the stock MAF and the stock program with HPP to increase rev limit, gearing, and fans etc. This was idle Ltrims though so I will go for a drive and see how it all looks at cruise. I might try a ported stock MAF and see what happens to the LTRIMS. I also had a couple of misfire codes but that is normal for my cam.
Talk about loud with the offroad Ypipe with dual 2.5 bullets in the Y with no catback LOL!
Anyways I will post my cruise results later for you all.
Thanks,
Chris
well the hard starting (cranking for a while before starting) is totally gone. Fires up right away now <img src="images/icons/grin.gif" border="0">
My LTRIMS are in the -6 range on one bank and the -2.x range on the other. I thought that was odd. I am running the stock MAF and the stock program with HPP to increase rev limit, gearing, and fans etc. This was idle Ltrims though so I will go for a drive and see how it all looks at cruise. I might try a ported stock MAF and see what happens to the LTRIMS. I also had a couple of misfire codes but that is normal for my cam.
Talk about loud with the offroad Ypipe with dual 2.5 bullets in the Y with no catback LOL!
Anyways I will post my cruise results later for you all.
Thanks,
Chris
12-08-2001, 11:24 PM
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Re: Need your help with FLAT HP curve. Chris,
I think you may be runnng a little too rich with the cats on now, check your wide band graph and see if you are lean trimming after your torque peak. Good luck!
Joe.
I think you may be runnng a little too rich with the cats on now, check your wide band graph and see if you are lean trimming after your torque peak. Good luck!
Joe.
12-09-2001, 06:50 AM
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Re: Need your help with FLAT HP curve. Thanks Joe <img src="images/icons/smile.gif" border="0">
I am going to wideband the car again when I get a full catback on it <img src="images/icons/smile.gif" border="0"> The car is screaming at the track so I am not too concerned about peak HP numbers but a nice smooth power band under the curve.
Thanks again for your advice I will check it out with ATAP today.
Chris
I am going to wideband the car again when I get a full catback on it <img src="images/icons/smile.gif" border="0"> The car is screaming at the track so I am not too concerned about peak HP numbers but a nice smooth power band under the curve.
Thanks again for your advice I will check it out with ATAP today.
Chris
