My 4age Definetly Needs Backpressure I Think

[ca18det_ae86]

hey pplz

just completed my 4ac to 4age 100kw 16v conversion .

i got a set of extractors 4-2-1 that end up siting along side the end of the gearbox .

i took it for a drive , besides the extremly loud freaky noise it makes with no exhaust , the car absolutly went no were .

I'm guessing this is because my car needs the full exhaust system , and it doesnt have back pressure . i mean it was just loud for nothing , had no pull had really nothing more then the 4ac motor i had in

there b4 .

i no the motor isnt anything fasttttt but some1 please tell me its only exhaust i have to do 2 get the power from this thing

[ca18det_ae86]

also if some1 can tell me the best size combination for this setup would be , I'm guessing 2and a quater with a 3inch cannon at the end 2 quit the thing down a little bit and give her a more crispy note

[rob83ke70]

you want the end of the pipe a bit smaller than the start, the gas will have cooled down and lost some of its velocity when it gets there, if you make the pipe size smaller then the gas speed increases again.

 

Robert.

[altezzaclub]

..and the exhaust is quite likely to have very little to do with the power! Think of race cars 30years ago that really just had tuned headers and no pipes or mufflers! It may cost you power low down but then it should get up and go!

 

One time we broke the exhaust off on the rally car under the passenger's feet and it suddenly went like a scalded cat!

 

If you want a 'flat' engine (assuming things like compressions are OK) then cam timing is the way to do it! Also ignition timing will kill power being either too advanced or too retarded.

[cuppas]

backpressure dramas end at the extractors though? i was under the impression it made little difference after them

 

whats the condition of the engine?

[towe001]

whats the condition of the engine?

+1 on that

 

compression test, a vacuum gauge onto the intake manifold and a tune up

[kiahn]

yeh just sounds like you need to do a basic tune on the thing

oh and btw ive heard that backpressure can be a bad thing for 4age's as they get older, causing the cam covers to leak oil and such

[Sam_Q]

it's not back-pressure, only turbine engines need it to run properly. I have done my own testing on a bigport and have found it very sensitive to any restrictions

[kiahn]

2.25 inch system MINIMUM if you want any sort of performance out of it, ive got 2.5 and it goes pretty nicely in all rev ranged and pulls all the way to 7500

[towe001]

Crikey its only a 1.6 not a 3.6

[Johno]

The exhaust made a MASSIVE different for my 4age. Before it was not reeving over 2,500rpm, misfiring, took it for a drive and it was hardly any power at all, fitted the second manifold piece and high flow cat and still bloody loud but a small increase in power. Got the stock 4ac exhaust all bolted in and power now :) rev;s fine.

[Sam_Q]

old thread dig up time

[Johno]

Yeah i know but I thought i should share my experience with others when i thought my 4age engine was stuffed. It was misfiring and the oil was milky and no power at all. I chucked on an exhaust and all good now. :jamie:

[Sam_Q]

and what system did you have before

[ke70dave]

Yeah i know but I thought i should share my experience with others when i thought my 4age engine was stuffed. It was misfiring and the oil was milky and no power at all. I chucked on an exhaust and all good now. :jamie:

 

 

so the exhaust sucked the water out of your oil?

 

man thats awesome!

 

should market those to people with blown headgaskets.

 

----

 

i took my 4age for a spin with it straight off the extractors, went ok, but it was tooooooo loud to go too quick....

 

just get an exhaust then you can test drive to your hearts content.

 

if you have lost power then its prolly cam timing or ignition timing.

 

but the original poster has prolly worked that out by now..