Exhausts like the old school racing cars????

[Guest vhpacer73]

How can you tune your car to make power with a short exhaust?(like the old racing cars at bathurst, about half a metre after the extractors)Because i did it to my old ke35 gravel basher and it had way less power than with the standard exhaust??? I just thought it would sound cool with the lumpy cam but it has lost heaps of power. so yea... how can you tune her for it???

Thanks

[SYKOV6]

i guess it depends on the mods to the engine. i can advance the ignition a extra couple of degrees and go 1 size up on the main jets with open headers. with this done it is super responsive and sounds like a top fueller. my engine was built with running no exhaust in mind[at the drags] and has the max mods to heads /valves/cam to allow for full on air flow with open pipes. i also have 1 3/4 in tube headers and 10.5-1 comp. my engine builder says i could pick up as much as 5-10 hp depending on what fuel im using [98road-av drags]

[Guest dreadedretard]

what about back pressure?

[lowlancer]

Just chuck a coby up its date

[isnowi]

The oldschool trick to work out ideal exhaust length is to draw a line up the pipe with a grease crayon, where the grease melts to is the ideal length, as thats where the gases are hot, and flowing well through the pipe and aiding efficient extraction.

[durty]

haha, what an awesome way of doing it

[CaMpylobacter]

that's how ya work out where to put balance pipes as well, with thermo crayons

[SYKOV6]

as a rule long collectors are good for low down and mid range power and short ones are for top end. i have short ones only about 150mm long and my engine is pretty shy of bottom end until about 3500rpm where the cam and heads start working together then shes all good to 7500