So why would my 408 make more TQ than HP when.....
06-21-2005, 03:00 PM
#1
So why would my 408 make more TQ than HP when..... Every other 408 Ive seen numbers for on this site makes more HP than TQ? Is it maybe a not getting air in and out problem? I am still running a LS6 intake and only 1 3/4 headers. I dont understand why mine would be the only one that makes more TQ than HP.
06-21-2005, 03:20 PM
#4
Originally Posted by GregWS6&z28
huh? you say everyone else makes more HP and TQ then you say you make more HP and TQ ???
What I am saying is every other 408 I have seen makes more HP than TQ. My car on the other hand made more TQ than HP and I was just wondering if nayone had any ideas as to why my car would do that.
06-21-2005, 03:50 PM
#6
Motor is running out of breath at the higher RPM's where cylinder filling is much more difficult because it only has tiny fractions of a second to get the job done. It is definately airflow related and might not be one factor but cumilative effect of many. The headers aren't hurting you as much as you think (power wise) and are actually helping to enhance the TQ. A 1.75 tube doesn't really start hurting you till you're well into the 500+ RWHP figures. Lou (LG) has dyno'ed quite a few 550 ish RWHP cars with 427 CID engines, AFR 225's, and extra long (restrictive) 1.75 primary pipes. Keep in mind that the larger motor will be even more difficult to feed at higher RPM's and places an even heavier burden on cylinder heads, exhaust, intakes, etc.
Perhaps your having some valve float issues at higher RPM's which might be hurting your power....Any graghs to post??
Tony M.
PS...Also, a cam in the 230's is somewhat conservative with that much displacement although with the right combination should have eclipsed the 500 RWHP mark without a problem.
Perhaps your having some valve float issues at higher RPM's which might be hurting your power....Any graghs to post??
Tony M.
PS...Also, a cam in the 230's is somewhat conservative with that much displacement although with the right combination should have eclipsed the 500 RWHP mark without a problem.
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06-21-2005, 03:50 PM
#8
Where does the HP peak at? I will bet you that you aren't getting enough air.
You have three problems then:
1) LS6 intake is choking it out at the higher RPMs
2) 1-3/4" headers are choking it at the higher RPMs
3) Your cam is too small and it is on a 110 icl, retard it 4 degrees and that will pick up top end horsepower
With that said, you have a nice setup for mid-range torque and driving around on the street. However, you could probably get 510-520rwhp out of that thing with an FAST LSX 90, QTP 1-7/8" HVM Headers, and retarding the cam 4 degrees. You'll lose some torque, but not much with those changes. Or, pull the cam and go with a Comp 244/248 on a 112+0 or 114+2 to remain nice an streetable. That would put you around 530rwhp with the less than stellar Patriot heads.
You have three problems then:
1) LS6 intake is choking it out at the higher RPMs
2) 1-3/4" headers are choking it at the higher RPMs
3) Your cam is too small and it is on a 110 icl, retard it 4 degrees and that will pick up top end horsepower
With that said, you have a nice setup for mid-range torque and driving around on the street. However, you could probably get 510-520rwhp out of that thing with an FAST LSX 90, QTP 1-7/8" HVM Headers, and retarding the cam 4 degrees. You'll lose some torque, but not much with those changes. Or, pull the cam and go with a Comp 244/248 on a 112+0 or 114+2 to remain nice an streetable. That would put you around 530rwhp with the less than stellar Patriot heads.
06-21-2005, 03:52 PM
#9
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It's because you make peak torque too low in the RPM band. Basically it's because you're running out of air (Your heads aren't good enough). You need better heads and bigger headers.
06-21-2005, 04:30 PM
#13
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Seems like a breathing issue as everyone has stated.
The HP is peaking around 5500 which is quite low.
On a side note, sort of cute how people are treating HP as a "force".
I'd rather have 360 ft./lbs. @ 2500 RPM & 340 HP @ 6000 RPM
than
450 ft./lbs.@ 2500 RPM & 300 HP @ 6000 RPM.
for my street/strip car.
The HP is peaking around 5500 which is quite low.
On a side note, sort of cute how people are treating HP as a "force".
I'd rather have 360 ft./lbs. @ 2500 RPM & 340 HP @ 6000 RPM
than
450 ft./lbs.@ 2500 RPM & 300 HP @ 6000 RPM.
for my street/strip car.