another exaust question

[P Plater]

twin systems... are the worth it... i understand to get rid of that yukky cackling a cross over pipe between the 2 banks s nessesary...

can any one give me tips or whatever it will be going on a mildly modified VR 5lt ute with cam chip extracters etc... it has an after market exaust but i want a twin system mainly becasue i want teo pipes out the back not just 1... the currest exaust isnt standard a 2.5inch system of some sort with lots of mufflers (like 3)

any comments??

[VXEXEC350]

My Gen111 has a twin 2.5" system with a merge rather than balance pipe. My 5.0 Litre VN has a twin 2.25" system into twin cats then they merge into a 3" system. there is one redback straight through muffler and a redback reso. The system works well on a sedan, and it sounds great...albeit a tad loud inside. I understand that the systems I am running are what are generally accepted to be the best for each car.
BTW both are running headers, the gen11 has pacies (4>1) AND THE VN has HSV tri Ys.

[P Plater]

im not sure what extracters mine are... there stainless something ones custom made 4into 1 i think...
so twin 2.5 isnt a good idea on a 5lt???

[bobg]

im not sure what extracters mine are... there stainless something ones custom made 4into 1 i think...
so twin 2.5 isnt a good idea on a 5lt???
Don't know where you got the impression that a twin 2.5" is not good on a 5L.

I am running stainless steel pacie tri Ys [HPC coated] into a custom dual 2.5" stainless system right to the rear with opened out GenIII cats [2.5" in and out] a merged pipe system after the cats, very large mufflers and very large resonator [all custom made by Johnny O] and it is very quiet when driven sedately [in my opinion] but my missus says she hears me coming several blocks away. [no comments please!!!]

It is a naturally aspired 5.7L stroker true but delivers massive torque low down for an NA system [over 400 (transmission ratio corrected) Nm at the tyres from 2000 RPM to 5700 RPM and 500 Nm at the rear between 3500 and 4500 RPM - these equate to flywheel torques of over 650 Nm between 3500 and 4500 RPM and over 600 Nm at the flywheel between 3000 and 5100 RPM with a peak of 660 Nm at 3500 and still over 650 Nm at 4500 RPM]

Cannot knock a well designed twin 2.5" on those figures.

All I need now is a clutch that can take the torque at low revs in spirited launches. The time needed to allow the clutch to fully engage before really putting the boot in would knock seconds off my 1/4 times I reckon.

Running a 3.46 diff at the moment but maybe I need to go to 3.9s to ease the load on the clutch???? :D :D

regards

bobg

[HRT Stroker]

im not sure what extracters mine are... there stainless something ones custom made 4into 1 i think...
so twin 2.5 isnt a good idea on a 5lt???


if the engine is stock or very mild and especially with an auto twin 2.25 inch is the way to go, twin cats etc etc. Twin 2.5 inch on a stock 5.0 auto will drop low end torque which may make it a bit doughy with the stock 3.08 diff.

If its a manual or has had some compression and head work, then the twin 2.5 inch will be fine.

The trick here is gas velocity and scavenging, the smaller diameter the pipe the better gas velocity maintained. The balance between power output and pipe diameter is the key........