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Pretty Please - add it to our Events forum(s) and add to the calendar! >> Wedge TR8 Headers/Exhaust
- Thread starter chrisc
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I finally got registered at this place....
As Todd indicated, I'm doing some experimentation with TR8 headers for my ITS car. The gist of the thinking is that the old 4-2-1 Tri-Y, with 1 5/8 primaries was a good design at the time but header "thinking" has passed it by. Here's what I know for sure:
1. I ran Tr-ys from Woody (quality stuff, and still have them) my first couple of years. Car made about 150 whp, 195 wtq. This was a stock 3.5, just balanced, etc.
2. In my class, the 8 has class leading torque, suffers a bit on the top end. In the quest for better breathing and more top end power, I did the allowed IT head work (port matching the heads and intake manifold one inch in) and got Ted S. to sell me the actual 4 into 1 headers he ran on his Playboy endurance TR8 back in the 80s. They are old, and not in the greatest shape, and had LONG tubes for torque. We cut them down just a bit, and put the car back on the dyno. 160 whp, 190 wtq, but we moved the torque and power curve to the right a bit. Torque peaked around 3500/3600 rpm, which was about 300/400 rpm higher, and power at 5200 rpm.
3. The "new" thinking amongst IT engine builders is that most cars use too much primary. Smaller tubes scavenge better, as the gases move faster. For example, ITS 240zs make incredible power for their displacment -- a 2.4 liter overhead cam six will put out about 170 to 175 whp and nearly as much torque. Part of that equation is using 1 and 3/8 primary tubes on the headers. Given that the 240 has six cylinders, a 1 3/8 tube would, you would think, work on the 3.5 as well.
Have had some difficulty in getting someone to fab up a set. Woody had a guy who was going to do it but found out tonight that he bagged it on Woody, so I'm looking for some one local. I'll give you dyno numbers once we get a set made.
Of course, the big news is we are ditching the Strombergs this coming off season (just after we got them working well, of course....lol..) and going FI. While the plenum on the Federal injection system is a bit constrictive, the intake manifold is MUCH better than the pent roof carb manifold we have to run in ITS. Like 20% more flow BEFORE port work. Couple this with a Haltech engine management system to cure the Lucas ECU's fueling problems (it basically DOESN'T fuel over 4500 as best we can tell) and we are expecting big things for this motor.
There is anecdotal reporting of a 9.35:1 3.5 in England in an MGB GT V8 with the Federal system making about 185/190 hp at the wheels. I have to run 8.6:1 compression, but should make up any other losses with a better exhaust, and the allowed head porting. I'm expecting the same, which would really make this car a beast in ITS (I'm presently a 2nd to 5th place car).
As Todd indicated, I'm doing some experimentation with TR8 headers for my ITS car. The gist of the thinking is that the old 4-2-1 Tri-Y, with 1 5/8 primaries was a good design at the time but header "thinking" has passed it by. Here's what I know for sure:
1. I ran Tr-ys from Woody (quality stuff, and still have them) my first couple of years. Car made about 150 whp, 195 wtq. This was a stock 3.5, just balanced, etc.
2. In my class, the 8 has class leading torque, suffers a bit on the top end. In the quest for better breathing and more top end power, I did the allowed IT head work (port matching the heads and intake manifold one inch in) and got Ted S. to sell me the actual 4 into 1 headers he ran on his Playboy endurance TR8 back in the 80s. They are old, and not in the greatest shape, and had LONG tubes for torque. We cut them down just a bit, and put the car back on the dyno. 160 whp, 190 wtq, but we moved the torque and power curve to the right a bit. Torque peaked around 3500/3600 rpm, which was about 300/400 rpm higher, and power at 5200 rpm.
3. The "new" thinking amongst IT engine builders is that most cars use too much primary. Smaller tubes scavenge better, as the gases move faster. For example, ITS 240zs make incredible power for their displacment -- a 2.4 liter overhead cam six will put out about 170 to 175 whp and nearly as much torque. Part of that equation is using 1 and 3/8 primary tubes on the headers. Given that the 240 has six cylinders, a 1 3/8 tube would, you would think, work on the 3.5 as well.
Have had some difficulty in getting someone to fab up a set. Woody had a guy who was going to do it but found out tonight that he bagged it on Woody, so I'm looking for some one local. I'll give you dyno numbers once we get a set made.
Of course, the big news is we are ditching the Strombergs this coming off season (just after we got them working well, of course....lol..) and going FI. While the plenum on the Federal injection system is a bit constrictive, the intake manifold is MUCH better than the pent roof carb manifold we have to run in ITS. Like 20% more flow BEFORE port work. Couple this with a Haltech engine management system to cure the Lucas ECU's fueling problems (it basically DOESN'T fuel over 4500 as best we can tell) and we are expecting big things for this motor.
There is anecdotal reporting of a 9.35:1 3.5 in England in an MGB GT V8 with the Federal system making about 185/190 hp at the wheels. I have to run 8.6:1 compression, but should make up any other losses with a better exhaust, and the allowed head porting. I'm expecting the same, which would really make this car a beast in ITS (I'm presently a 2nd to 5th place car).
DNK
Great Pumpkin
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Jeff, WELCOME. Love the vids on Woody's. Cept the last 1. The 260 got left in the dust.Waiting for your video for the next race.
In your exhaust talk how would this concept work for a street car. Do you think the smaller Primaries are better on a street set up?
I am really toying with buying Woody's or having a set built locally for my street car.
Keep the wheels pointing down and more videos coming.
Don
In your exhaust talk how would this concept work for a street car. Do you think the smaller Primaries are better on a street set up?
I am really toying with buying Woody's or having a set built locally for my street car.
Keep the wheels pointing down and more videos coming.
Don
Yeah, Ron just wasn't up to speed that race and we left him behind very quickly. I had a great race with that 325 and got around him pretty early...then had to keep him there. Those cars have as much torque as we do.
Woody's is high quality stuff, you can't go wrong there. Plus, a custom set is expensive and I'm using it to solve a very "narrow" problem - how to move the torque and power band "up" the RPM curve a bit on an essentially stock 3.5.
Not sure how much of that translates to the street. On the street, for most of what I would do (cruising around town) more torque down low is what you want so the Tri-Y is probably perfect for that application. DEFINITELY use a cross over -- in fact an "X" is better (on the dyno) than a balance pipe, and if you can live with the look a single pipe is even better than that (Y pipe we call it).
So, for a street car, I'd probably use Woody's Tri-Ys, coated to help keep the engine bay temps down, then have an exhaust guy take them from there -- for the cats and the balance tube, and then out the back.
I'm racing in Savannah end of April. Should have my vid setup working then so I will actually have in car from the 8 there.
Woody's is high quality stuff, you can't go wrong there. Plus, a custom set is expensive and I'm using it to solve a very "narrow" problem - how to move the torque and power band "up" the RPM curve a bit on an essentially stock 3.5.
Not sure how much of that translates to the street. On the street, for most of what I would do (cruising around town) more torque down low is what you want so the Tri-Y is probably perfect for that application. DEFINITELY use a cross over -- in fact an "X" is better (on the dyno) than a balance pipe, and if you can live with the look a single pipe is even better than that (Y pipe we call it).
So, for a street car, I'd probably use Woody's Tri-Ys, coated to help keep the engine bay temps down, then have an exhaust guy take them from there -- for the cats and the balance tube, and then out the back.
I'm racing in Savannah end of April. Should have my vid setup working then so I will actually have in car from the 8 there.
MGA Steve
Jedi Warrior
Offline
Thanks everyone. 
I have been watching this thread since this topic started without saying anything, but have learned a lot. It's nice to be able learn from guys who are already trying all these different approaches instead of learning by (expensive) trial and error.
I have been watching this thread since this topic started without saying anything, but have learned a lot. It's nice to be able learn from guys who are already trying all these different approaches instead of learning by (expensive) trial and error.