AUII XR8 200kw - Torque Increase

[STINKY NINJA]

I never said hurricanes were a restriction at any point,i said my extractors were said to be a restriction.
I did say the have the same pipe sizes but a smaller collector.
Im not saying anything is right or wrong about your setup t man but ive been stung a few times listening to advice on aff and its cost me dollars,that makes you want proof before outlaying $$$$$
I only ever wanted some proof why pacies are worse off than hurricanes,its kind of got off track a bit,from what I can see its a trade off.
Bigger primaries and smaller collector against smaller primaries with a bigger collector which needs a further restriction in the exhaust to counteract the bigger collector,definitely is a trade off,or am I misinterpreting the info im reading?
That's why I said is it just a marginal thing?
6 of one,half a dozen of the other.
that's the way I see it.

[T MAN]

Fair enough but you did say that you headers had the same primary pipes as the hurricanes meaning that there is a possibility that the hurricanes could also be a restriction. But just to add. While my car is supercharged its a centrifugal supercharger and does not make any boost untill around 2500 to 3000rpm. In saying that the hurricanes were fitted before the car was supercharged. . While I honestly cant compare them directly with the pacemakers. I did remove a set of hm headers for the hurricanes and they made a slight improvement in low to mid torque.. But this is just my experience with my car and what works for one doesn't always work for another.

[STINKY NINJA]

Originally Posted by T MAN

Fair enough but you did say that you headers had the same primary pipes as the hurricanes meaning that there is a possibility that the hurricanes could also be a restriction. But just to add. While my car is supercharged its a centrifugal supercharger and does not make any boost untill around 2500 to 3000rpm. In saying that the hurricanes were fitted before the car was supercharged. . While I honestly cant compare them directly with the pacemakers. I did remove a set of hm headers for the hurricanes and they made a slight improvement in low to mid torque.. But this is just my experience with my car and what works for one doesn't always work for another.

Hm says their headers only have a 2 1/8 collector,never mentioned pipe sizes though,id say that collector size may have been a factor.

[PridenJoy]

Don't think it will help much but.........my car came with a set of tri y pacies in the boot which i will be fitting in the next month or so, i know many here prefer the hurricanes but i have the pacies already so that's what I'll be using. The car is very close to being stock and currently has the factory headers and cats with twin 2.25 all the way. Once i fit the pacies with hi flow cats i will be sure to report any difference in driveability which I'm expecting quite a bit of difference over factory set up.

[STINKY NINJA]

I do appreciate the info you guys are giving me though.
I also have new ph4000 sitting in the shed,not sure if ill be selling them,keeping the ones I have fitted now or buying some other ones!
So much info to process,my brain is melting after dealing with my daughter all day.

[STINKY NINJA]

My hitech extractors aren't even mandrel bent... ffs

[Sox]

Originally Posted by STINKY NINJA

My hitech extractors aren't even mandrel bent... ffs

Neither are my custom made jobbies on the P250, nor is the rest of the system.

Shallow radius press bends have almost no negative consequence to flow.

[STINKY NINJA]

I suppose my ugly *** hitech anorexic headers might be called into service for a bit longer,like forever.
Thanks for all the info guys,might put this one to bed.

[BOTTLEDUP]

Leave the headers you have Shannon, I seriously doubt you'd notice enough of a gain to justify the change.

FWIW most of you know I fitted Difillipos to the TE along with bashed out cats (as received, it wasn't me officer!!), on the dyno we gained horsepower above 4800rpm, approximately 5hp by 6000. Below 4800 it was behind the stock headers and cats. Recently I had the original pipes refitted as I return the vehicle as close to stock as practical and the improvement in throttle response and torque right off idle is most definitely noticeable. 'Seat of the pants' feel rarely corresponds to a dyno figure, as a dyno cannot measure throttle response or rate of acceleration, and this is exactly where smaller diameter high velocity pipes (headers and cylinder heads as well) really shine.

[MrEL]

On our AUs Ive always just run the Standard Tickford Headers with the collector stretched out to 2.5" with a set of high flow cats.
Never done me any wrong yet.

[BOTTLEDUP]

Originally Posted by MrEL

On our AUs Ive always just run the Standard Tickford Headers with the collector stretched out to 2.5" with a set of high flow cats.
Never done me any wrong yet.

Yes this is an old trick I've seen done many times with good results.

[meanfalcon]

Just Had a look under my old XR8 I bought new. Got SVO to fit new system going back over ten years ago. I think it was a HM headers set with the cats welded straight on. Pressed bends but Tri Y design, with a 2 1/2" Red back single system. Don't forget the chrome tip. That gave quite a noticeable improvement in performance and fuel economy. Cut open the air box gave it a K&N, eagle leads and Iridium plugs and had it flash tuned. Was OK for an auto, My first ever pass at Calder got a 14.5.

[Bossxr8]

Exhausts are a brain melt. I've been pondering what to do with my hci NL. Currently its pacies, high flow cats and dual 2.25. Thinking of stepping up to dual 2.5 and cutting off the smaller pacie collectors and making them either 2.5 or 3 inch. Have no idea what the best way to go is though. Simular set ups to mine are making 350rwhp in the US so not sure if the 2.25 inch collectors on the pacies are big enough.

Now its no longer a daily im not too fussed about low down torque. With a high stall going in and already having 3.9's it wont matter too much anyway.

[OzriderXR8]

I've gotten the biggest performance boost I could have ever planned from a totally unexpected source.................getting the transmission fully serviced.

Beforehand the trans would hold onto a gear and not change down when you accelerated until you stomped on it, now the slightest pressure and it smoothly drops a gear, or two, and takes off.

I guess I'm now experiencing what it should have been like all along

[Blue Shadow]

Originally Posted by OzriderXR8

I've gotten the biggest performance boost I could have ever planned from a totally unexpected source.................getting the transmission fully serviced.

Beforehand the trans would hold onto a gear and not change down when you accelerated until you stomped on it, now the slightest pressure and it smoothly drops a gear, or two, and takes off.

I guess I'm now experiencing what it should have been like all along

What was done in the service and what did it cost, have you had a chance to look at fuel consumption yet?

[OzriderXR8]

Originally Posted by Blue Shadow

What was done in the service and what did it cost, have you had a chance to look at fuel consumption yet?

Basically a full service.. I dropped it off they did stuff I paid them.

Cost me $280 with the Speedo Actuator replaced.

Fuel consumption is actually looking pretty good since I got it done.

[Crazy Dazz]

Originally Posted by OzriderXR8

now the slightest pressure and it smoothly drops a gear, or two, and takes off.

No way a 4spd tranny should drop 1~2 gears at the "slightest pressure".

What speed are you doing when this happens, and how "slight" a pressure are we talking about?

[OzriderXR8]

Originally Posted by Crazy Dazz

No way a 4spd tranny should drop 1~2 gears at the "slightest pressure".

What speed are you doing when this happens, and how "slight" a pressure are we talking about?

Damn, have they broken it????

[Blue Shadow]

Whoops