Who manufactures 1-7/8ths headers for LT1's?
12-13-2006, 09:32 PM
#5
How wild you plan to go. IMO folks on this side of the LT1 thing are a bit too quick to jump on the bigger is better bandwagon in general, headers being the one in this case.
A few weeks ago another LT1 b-body slipped into the 9s, 9.7 at 138, solid roller 383 with stock pcm with two stages of juice and 4040lbs raceweight, still using 1 5/8" tri-Y style headers, by his own admission just for the plug clearance they offer but I still think it makes a point.
A few weeks ago another LT1 b-body slipped into the 9s, 9.7 at 138, solid roller 383 with stock pcm with two stages of juice and 4040lbs raceweight, still using 1 5/8" tri-Y style headers, by his own admission just for the plug clearance they offer but I still think it makes a point.
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12-14-2006, 08:54 AM
#10
Originally Posted by Stefan D.
Kooks and Heddman. I think the Kooks are a step like 1 3/4 to 1 7/8th. The Heddman are straight 1 7/8ths.
12-14-2006, 09:45 AM
#11
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Originally Posted by 96capricemgr
How wild you plan to go. IMO folks on this side of the LT1 thing are a bit too quick to jump on the bigger is better bandwagon in general, headers being the one in this case.
A few weeks ago another LT1 b-body slipped into the 9s, 9.7 at 138, solid roller 383 with stock pcm with two stages of juice and 4040lbs raceweight, still using 1 5/8" tri-Y style headers, by his own admission just for the plug clearance they offer but I still think it makes a point.
A few weeks ago another LT1 b-body slipped into the 9s, 9.7 at 138, solid roller 383 with stock pcm with two stages of juice and 4040lbs raceweight, still using 1 5/8" tri-Y style headers, by his own admission just for the plug clearance they offer but I still think it makes a point.
12-14-2006, 10:45 AM
#12
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Originally Posted by Sweetred95ta
Doesn't mean he wouldn't go faster with larger/better headers. When it comes to headers, I think bigger is better (as long as the headers are quality made).
12-14-2006, 11:16 AM
#13
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Originally Posted by Captainofiron
not necessarily, you can treat the outgoing exhaust gasses as a fluid, that being so the bigger the pipe, the lower the exhaust gas velocity, you get past a certain point in pipe diameter and the exhaust will be slow enough that it is hindering more gases from exiting the exhaust port and valve. As with all things there is a limit to how big is the best
12-14-2006, 05:52 PM
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The header tube size has to be matched to the power output of the engine.
You can go too big and lose power.
I helped a friend build a 640 hp pump gas 489 BBC. It made those #'s with 1 7/8 into 2 dyno headers. We swapped for 2 1/8 Hooker Super Comps and it lost almost 10 hp even with jet changes.
An LT1 has got to be pushing a lot of air to benefit from 1 7/8 headers. I myself am using 1 3/4 Jet Hots.
You can go too big and lose power.
I helped a friend build a 640 hp pump gas 489 BBC. It made those #'s with 1 7/8 into 2 dyno headers. We swapped for 2 1/8 Hooker Super Comps and it lost almost 10 hp even with jet changes.
An LT1 has got to be pushing a lot of air to benefit from 1 7/8 headers. I myself am using 1 3/4 Jet Hots.
12-15-2006, 07:09 AM
#16
Originally Posted by Sweetred95ta
Doesn't mean he wouldn't go faster with larger/better headers. When it comes to headers, I think bigger is better (as long as the headers are quality made).
12-15-2006, 07:41 AM
#17
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Originally Posted by CNC Stew
I helped a friend build a 640 hp pump gas 489 BBC. It made those #'s with 1 7/8 into 2 dyno headers. We swapped for 2 1/8 Hooker Super Comps and it lost almost 10 hp even with jet changes.
An LT1 has got to be pushing a lot of air to benefit from 1 7/8 headers. I myself am using 1 3/4 Jet Hots.
An LT1 has got to be pushing a lot of air to benefit from 1 7/8 headers. I myself am using 1 3/4 Jet Hots.
Last edited by Sweetred95ta; 12-15-2006 at 07:46 AM.
12-15-2006, 08:11 AM
#18
The dyno is not the track and more HP does not always mean faster.
One of the b-body guys an engineer by trade I believe did testing on his own car with a handful of different header designs all from the same manufacturer. Was heads/cam spray running mid 11s he found that between 1 5/8 Tri-Ys, 1 5/8 4-1 and 1 3/4 4-1 that the Tri-Ys made the car fastest and to get any advantage of the 1 3/4 he had to rev beyond 6800, yes they started gaining power long before that but in order to make up for the average power loss at lower rpms he had to rev that high. Now yes this was just a 350 and not a wild one but I think most and even the guy testing would have said for a juiced motor like that 1 3/4 would have been best.
In a perfect world I do believe 4-1 is better than tri-y BUT in the real world we have to make headers fit our chassis which complicates things a whole lot.
I am not trying to say tri-ys are always best just using an example where everyone would say 1 5/8 and tri-y are both wrong for such an application but real world testing not on a dyno proved otherwise.
IMO if you genuinely need 1 7/8 the car is wild enough you should be just custom building them because there wont be many off the shelf parts on the car anyway.
One of the b-body guys an engineer by trade I believe did testing on his own car with a handful of different header designs all from the same manufacturer. Was heads/cam spray running mid 11s he found that between 1 5/8 Tri-Ys, 1 5/8 4-1 and 1 3/4 4-1 that the Tri-Ys made the car fastest and to get any advantage of the 1 3/4 he had to rev beyond 6800, yes they started gaining power long before that but in order to make up for the average power loss at lower rpms he had to rev that high. Now yes this was just a 350 and not a wild one but I think most and even the guy testing would have said for a juiced motor like that 1 3/4 would have been best.
In a perfect world I do believe 4-1 is better than tri-y BUT in the real world we have to make headers fit our chassis which complicates things a whole lot.
I am not trying to say tri-ys are always best just using an example where everyone would say 1 5/8 and tri-y are both wrong for such an application but real world testing not on a dyno proved otherwise.
IMO if you genuinely need 1 7/8 the car is wild enough you should be just custom building them because there wont be many off the shelf parts on the car anyway.
12-15-2006, 09:15 AM
#19
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Originally Posted by Sweetred95ta
There are too many variables to claim that larger headers made your buddy lose power. Things like: the twists and turns of the primaries, equal length primaries or not, imperfections during the manufacturing process, etc. All these things are going to be different from header to header. You can't just assume that the larger header caused a power loss. In a BBC, a 2 1/8" header should make more power than a 1 7/8" header. The power could lie in the stepped design as well, you never know. Also, I'd be willing to bet that if you took a stock LT1 and bolted up some 1 3/4" lt's (Jet Hots) and did a dyno comparison with 1 7/8" lt's (KOOKS), the KOOKs would produce more power. I do understand where you guys are coming from with saying that bigger isn't necessarily better, I'm just picking brains and being bored.
I too was surprised at the power lose and I asked Bret Bauer about it because he provided the cam. He said at that power level 2" primaries would be about right.
1 7/8 headers on a stock LT1 would be a very bad mismatch.
Ask ABA 383 how much he picked up with his Kooks over mid-lengths.
12-15-2006, 10:24 AM
#20
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Originally Posted by 96capricemgr
...to get any advantage of the 1 3/4 he had to rev beyond 6800, yes they started gaining power long before that but in order to make up for the average power loss at lower rpms he had to rev that high.