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Discussion Starter · #1 ·
I'm trying to evaluate my DT header performance vs. a 6 to 1 header design. I'm running a 3" exhaust, the car is autox dedicated, power range is from 3500 up to 7000 rpm. The Doug Thorley style 6-2-1 header is most common, and seems to work ok (I have nothing to compare it to), but Raptor also offers a nice 6 to 1 header design. I figure they must each have their strengths and weaknesses, and was wondering what the CS membership opinion is on the two designs. Hard to find info on comparisons doing search. I can believe that each design has gains over a stock exhaust manifold, but not sure about the rpm ranges that each design is best. In general terms, from some of my readings, the 6-1 header has gains at upper rpms, whereas the 6-2-1 design has some gains across the rpm ranges.
Whaddaya all think?

George at Raptor has documented 10hp gains over stock with his 6-1 header, and I wouldn't hesitate to order from him, always been honest and courteous to me.

If anyone has both types available for weighing, I love a comparison weight. Gee, not asking much now, eh? :)

Thanks!

Don L.
 

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Well, I don't have any facts for you Don, but I do have a comparison.
Where I live, we go out to a spot, out in the country, it's a 15 mile stretch of road that has no houses or development on, and we race there. The race lasts about 2 miles usually.
When stock, we would race, from a dig, and would be dead even. All the way. Whoever got the jump from the start won, every time. Probably 10+ times, because we could never settle who was faster.

Fast forward a bit, and we both had done a RC Cai, Full 2.5 exhaust, no cat, and a header.
He had a Raptor racing header, I bought a doug thorley header.
Then we raced again.
Every race, I would have him till about 75-85 mph, by about a car, sometimes two. But regardless of what I did, he would pass me and put a car length or two on me. I could not win in the top end.
I think for the type of racing you do, you're better off with the thorley header you have. This is just my personal experience, and by no means fact, but without directly comparing the two on the dyno, it's as close as I think is possible. We even switched cars when racing, and had the same results, it was not just the driver.

Cliffs:
Racing 5m vs 5m with identical mod's except header brand, 6-1 wins past 80 mph.

Edit: I will weigh my doug thorley tomorrow for you. I don't have a raptor racing exhaust available to me that is not on a car though.
 

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Don;

for the last 2 years I've been trying to get the time/funds together to rent a dyno for a few hours to do some back to back testing with: factory; thorley and my header. Along with testing the difference between straight pipe; factor cat; ceramic cats and metallic cats. Hopefully Steve (tireshredder) and I can tackle it this year.

I know there will be tons to come on here and offer their opinion on the subject, but my opinion has always been that the only true way to answer this is with a dyno. Its the only way to eliminate variables that you just can't measure.

I can't tell you the weight of the Thorley but mine weighs 15.4lbs for just the header or 19lbs header and downpipe fully coated.
 

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Discussion Starter · #4 ·
Good feedback from both of you! Thanks!

Austin: not sure your info (few useful too, thanks!) would indicate to me that the DT header is better for my needs. From the rpm/mph charts, I'd guess you were probably around 4500 rpm when the Raptor header started pulling on you. That is a rpm area I'd like some additional hustle, as long as nothing terribly detrimental occurs below the 4500 rpm level. Like giving my car V-tec, I suppose?

George: I have enough dyno plots for my car, and fairly consistent too, that if the 6-1 header offered any gains, I'd be comfortable supporting the gains are attributable to the header. What is the availability of the header?

I definitely welcome any and all thoughts/opinions on this. Thanks!

Don L.
 

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If you want to do a dyno comparison on RaptorRacing 6-1, I got one in the garage. You would need a new downpipe made for the Supra.
I can lend it to you for testing if you wish, but when I'm done with the smog on my car the header's going back in.
 

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my opinion (but this could be hog wash)

In general terms, from some of my readings, the 6-1 header has gains at upper rpms, whereas the 6-2-1 design has some gains across the rpm ranges.

Whaddaya all think?

Don L.
well that sound kinda right the 6-1 make more upper cuz of less flow restriction 6-2-1 has a little bit more flow restriction cause the all around rpm power gain

its all up to you do you want to bring out the top end a little bit more or give it a lil more bottom end.

but as i said this could all bu hog wash
 

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Discussion Starter · #8 ·
If you want to do a dyno comparison on RaptorRacing 6-1, I got one in the garage. You would need a new downpipe made for the Supra.
I can lend it to you for testing if you wish, but when I'm done with the smog on my car the header's going back in.
That's a great offer! I appreciate it. What time frame are you looking at? I could do a "close" to back to back dyno test. Might not be same day, but values should still be useful. So a downpipe with a 2 bolt flange on inlet (from 6-1 collector) needs to be made going to my exhaust system (which has a 2 bolt 3" flange) ?

The downpipe inlet on yours is currently 2.5" ? I have to give this some serious consideration and let you know. Sounds like a fun test project.

Another question, anyone have a picture of a 6-1 header? George? I've been digging around old for sale postings, and found a bunch of DT headers, Pacesetters (I can appreciate why folks prefer the DT), but not much pics on a 6-1 or a Tri-Mill style.

Don L.
testing for power....
 

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If he was dragging, wouldn't he be shifting out of 3rd at 75 mph (~6500 rpm) and not at 4500 rpm? With the stock gear ratios best acceleration should occur by staying in gear to 6500 rpm stock.

Good luck with the comparison test. Why do you need a dyno? Find a steep hill with fairly constant grade and accelerate up it in 2nd and carefully measrure the time it takes to go from 3000 to 6500 rpm (or any rpm interval of interest).
 

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Discussion Starter · #12 ·
If he was dragging, wouldn't he be shifting out of 3rd at 75 mph (~6500 rpm) and not at 4500 rpm? With the stock gear ratios best acceleration should occur by staying in gear to 6500 rpm stock.

Good luck with the comparison test. Why do you need a dyno? Find a steep hill with fairly constant grade and accelerate up it in 2nd and carefully measrure the time it takes to go from 3000 to 6500 rpm (or any rpm interval of interest).
Hey Stan, I think you are right, but he mentioned that 80 mph and above the 6-1 header pulled on him. I assume that means he must be in 4th by then, and they are going from 80 mph to 110 mph (approx). That I estimate is a rpm range (after shifting) from 4500rpm to 6500 rpm. I'm just shooting off the top of my head, though.

Why a dyno? Folks like numbers, especially dyno numbers. I like to compare hp and torque figures at various rpm values, including the respective a/f ratios. That's just me.

Don L.
 

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Hey Stan, I think you are right, but he mentioned that 80 mph and above the 6-1 header pulled on him. I assume that means he must be in 4th by then, and they are going from 80 mph to 110 mph (approx). That I estimate is a rpm range (after shifting) from 4500rpm to 6500 rpm. I'm just shooting off the top of my head, though.

Why a dyno? Folks like numbers, especially dyno numbers. I like to compare hp and torque figures at various rpm values, including the respective a/f ratios. That's just me.

Don L.
We both were shifting at redline-6500rpm's, at every gear change. He wouldn't start to pull on me until the very end of third gear, and all through 4th gear. I forgot to mention originally, but from a 2nd gear pull, at 40mph, we ran, and had the same results. My 2nd gear was faster, I got to redline and shifted before him, but he would then proceed to catch me right at 85 mph.

I thought you might like that picture don, that header is a nice addition to the engine bay, and sounds incredible. I definitely enjoy the sound from it more then the doug thorley's I have on both my cars.
 

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DonL,

Do you think that it is truly necessary to collect dyno info for this specifically? Of all the dyno graphs out there, might it be possible to compare stock engine dynos to determine if there are any noticable trend differences between them?

Of course, if the dyno runs were performed on the same motor they would help to eliminate variability...

Regards,

Carlos
 

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Yes, real stock, 6-2-1, 6-1 dyno runs on the SAME vehicle are necessary. Nobody's got a Brand New Toyota Fresh (from Toyota) 5M-GE in their cars. Or if they do... they're not available. The comparisons would be skewed by engine wear.
 

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That's a great offer! I appreciate it. What time frame are you looking at? I could do a "close" to back to back dyno test. Might not be same day, but values should still be useful. So a downpipe with a 2 bolt flange on inlet (from 6-1 collector) needs to be made going to my exhaust system (which has a 2 bolt 3" flange) ?

The downpipe inlet on yours is currently 2.5" ? I have to give this some serious consideration and let you know. Sounds like a fun test project.

Another question, anyone have a picture of a 6-1 header? George? I've been digging around old for sale postings, and found a bunch of DT headers, Pacesetters (I can appreciate why folks prefer the DT), but not much pics on a 6-1 or a Tri-Mill style.

Don L.
testing for power....
Don;

if you want to borrow that header I can send you a coated downpipe to test with. In regards to availability: I'm just finishing the write up's/pix for a MK2/3 Exhaust group buy which will be up shortly.

If you want this downpipe I'll send it down to you free of charge as long as I get to have a copy of the dyno for my reference.

Fire me off an email if you decide to borrow it from Xiong and want to grab the DP off me.
 
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