cjsupra90
New Member
Hey guy's Im posting here a bit of info about the Stainless headers (extractors) that I am building for my MKIII Supra swap. There is a thread about it in the Supra swap section, but John (JBrady) asked me to do a thread in the exhaust section too so here it is.....
They are (will be) fully stainless, all piping is 304L and the head flanges are 347 (the high dollar good crap and didn't cost me a dime :evil: ) Yes, they were free but only because the place that I was working at up until last week (got laid off) used 347 for a lot of stuff that we built and it was scrap material and we had a laser cutter there. They are Tri-Y (4-2-1) design. Pipe size layout (although a bit different from standard norms) are 1.5" primary's, 1.875" secondary's and 2.5" final collectors. I know that the secondary's and final collector might seem a bit large but I am doing this based on some info that was giving to me by a guy that build header for Jaguar 4.0l v8's. Based on what he told me and showed me dyno plots, this gave a better average torque curve throughout the entire RPM range of the motor. He showed me 12 differant dyno plots (4sets of 3 for an average of each set up). The setups where all done with the same 2.5" duel exahust. The first set was with stock manifolds, the second set was with more normal sized (1.5", 1.75", 2" megaphoned to 2.5") tri-Y's, the third set what with 4 into 1 (1.5" primary's, 2.5" merged collector) and the forth was the set up like what Im doing....
The first setup was a baseline (car alread had the 2.5" exhaust on it).
The second setup ( more normal sized Tri-Y ) showed nice gains in the low range and tapered off through the mid range with very little gain above 5200RPM.
The third Setup (4 into 1) showed a small loss in the low range, a slight gain in the mid range and good gains in the high range
The forth setup (Tri-Y but with bigger tubes for the secondary's and collectors) show not as much gain in the low range as the standard tri-y's more mid range then any other setup, and not quite as much gains in the top end like the 4 into 1's.
Basically that setup showed a much flatter torque curve then any other setup and was noticably stronger then the baseline through out the entire RPM range of the engine
I dont remember the number to be exact, but I do know that all pulls where done on an engine dyno, not a chassis dyno and all were done from 1500 to 7000 RPMs...
If I can find a way to get back in touch with him, I'll see if he will let me post the dyno plot's with all the exact specs for each setup.
I'd love to baseline my setup but that base line will be with everything Im gonna do performance wise with the exception of possibly a supercharger or turbo's at a later date so there would be nothing to compair it to being that everything that is going to be done, will be done the first time the car is started with the swap...
Anyways, here are some pictures of the progress.... Currently only working on the Drivers side as it is the tight harder side having the steering shaft there and being a left hand drive car, it also happens to be the side that cylinders get skipped when grouped (i.e. 1&5 and 3&7 are the matched pairs) where as the right side is grouped 2&4 and 6&8
Sorry for the lack of image quality. As usual, everytime I go and do any work on anything, I forget to bring the camera and have to rely on my phone. (and as we all know, 1.3 megapixel is not that great)
Here are the primary's tacked together.
A couple of pix of the collector pieces being cut.
All 4 of the primary to secondary 2 into 1 merge collectors welded up.
The 2 secondary to final collector merges welded up.
A few other shots of the 2 into 1 units. (dont remember which ones are which. They might even all be of the same one. Its been a while since I did them)
A couple of shots of the most recent work which is the primary's welded, first set of collectors welded and one of the seconday's welded (but not complete. The other primary to secondary still has to have the end cut before the seconary gets welded on, then both seconday's will be finsh and joined with the last collector into the main collector body.
Lastly, here are a couple of pix showing the fitment on a bare block and head in a A70 supra chassis (thanks to Jake ans Sean). The clearance is far better then I thought it would be. One thing to note, these are being build on a engine Jig that I have at the house and just going off of dimensions taken from a car. Doing it this way, I was really worried about putting all this time into it only to find out that they interfer with the steering shaft, but needless to say, there is a mile of clearance afterall as you can see below....
Im still haven't decided as to what type of flanges to use for connection to the exhaust (2bolt, 3bolt, V-band). Im kinda siding towards V-bands...
Well thats it for now, Im open to comments, questions or suggestions if anyone has any, feel free.....
They are (will be) fully stainless, all piping is 304L and the head flanges are 347 (the high dollar good crap and didn't cost me a dime :evil: ) Yes, they were free but only because the place that I was working at up until last week (got laid off) used 347 for a lot of stuff that we built and it was scrap material and we had a laser cutter there. They are Tri-Y (4-2-1) design. Pipe size layout (although a bit different from standard norms) are 1.5" primary's, 1.875" secondary's and 2.5" final collectors. I know that the secondary's and final collector might seem a bit large but I am doing this based on some info that was giving to me by a guy that build header for Jaguar 4.0l v8's. Based on what he told me and showed me dyno plots, this gave a better average torque curve throughout the entire RPM range of the motor. He showed me 12 differant dyno plots (4sets of 3 for an average of each set up). The setups where all done with the same 2.5" duel exahust. The first set was with stock manifolds, the second set was with more normal sized (1.5", 1.75", 2" megaphoned to 2.5") tri-Y's, the third set what with 4 into 1 (1.5" primary's, 2.5" merged collector) and the forth was the set up like what Im doing....
The first setup was a baseline (car alread had the 2.5" exhaust on it).
The second setup ( more normal sized Tri-Y ) showed nice gains in the low range and tapered off through the mid range with very little gain above 5200RPM.
The third Setup (4 into 1) showed a small loss in the low range, a slight gain in the mid range and good gains in the high range
The forth setup (Tri-Y but with bigger tubes for the secondary's and collectors) show not as much gain in the low range as the standard tri-y's more mid range then any other setup, and not quite as much gains in the top end like the 4 into 1's.
Basically that setup showed a much flatter torque curve then any other setup and was noticably stronger then the baseline through out the entire RPM range of the engine
I dont remember the number to be exact, but I do know that all pulls where done on an engine dyno, not a chassis dyno and all were done from 1500 to 7000 RPMs...
If I can find a way to get back in touch with him, I'll see if he will let me post the dyno plot's with all the exact specs for each setup.
I'd love to baseline my setup but that base line will be with everything Im gonna do performance wise with the exception of possibly a supercharger or turbo's at a later date so there would be nothing to compair it to being that everything that is going to be done, will be done the first time the car is started with the swap...
Anyways, here are some pictures of the progress.... Currently only working on the Drivers side as it is the tight harder side having the steering shaft there and being a left hand drive car, it also happens to be the side that cylinders get skipped when grouped (i.e. 1&5 and 3&7 are the matched pairs) where as the right side is grouped 2&4 and 6&8
Sorry for the lack of image quality. As usual, everytime I go and do any work on anything, I forget to bring the camera and have to rely on my phone. (and as we all know, 1.3 megapixel is not that great)
Here are the primary's tacked together.
A couple of pix of the collector pieces being cut.
All 4 of the primary to secondary 2 into 1 merge collectors welded up.
The 2 secondary to final collector merges welded up.
A few other shots of the 2 into 1 units. (dont remember which ones are which. They might even all be of the same one. Its been a while since I did them)
A couple of shots of the most recent work which is the primary's welded, first set of collectors welded and one of the seconday's welded (but not complete. The other primary to secondary still has to have the end cut before the seconary gets welded on, then both seconday's will be finsh and joined with the last collector into the main collector body.
Lastly, here are a couple of pix showing the fitment on a bare block and head in a A70 supra chassis (thanks to Jake ans Sean). The clearance is far better then I thought it would be. One thing to note, these are being build on a engine Jig that I have at the house and just going off of dimensions taken from a car. Doing it this way, I was really worried about putting all this time into it only to find out that they interfer with the steering shaft, but needless to say, there is a mile of clearance afterall as you can see below....
Im still haven't decided as to what type of flanges to use for connection to the exhaust (2bolt, 3bolt, V-band). Im kinda siding towards V-bands...
Well thats it for now, Im open to comments, questions or suggestions if anyone has any, feel free.....
