hi i have an '82 4kc and 5 speed going into a 1965 Honda S600,

 

i have 1.5 inch SU's on a Lynx Manifold ( yes i got one new yeah)

 

and i have an early corolla exhaust manifold, sort of a extractor with twin outlets

 

i'm thinking of running the twin pipes all the way to the muffler ( at the rear)

 

and then to twin outlets.

 

how do you think this will work, any sugestions on pipe diameter

 

Ewen

Best bet is to keep it simple....Corolla engines need a certain amount of backpressure to produce max power.....by adding another pipe to the rear of the car you could be effectively reducing the amount of backpressure at the manifold (depending on pipe diametre of course)....best bet is to run a single pipe diametre of around 1"3/4 or 2"....straight to a sports muffler. The manifold you have used to run like a 4 - 2 -1 extractor setup (tri Y) where the manifold comes into 2 pipes, the pipes were then taken down to just a little past the passenger footwell and then joined into one pipe.

Edited October 24, 200718 yr by Xany

I guess it depends what you want to achieve with your car. If the S600 is the car I'm thinking of, you probably don't have a hell of a lot of space?

 

Unless it's an all out race weapon, I'd probably have two outlets from the exhaust manifold, and join them downstream a little. Do a web search, there are a few formulas around for calculating primary length. I'd say you want to join the pipes somewhere around a metre downstream from the side of the head, for a pretty stock 4k with a torque peak of around 4500rpm.

 

1.75 is probably as big as you need. More than that will probably just make it noisy.

thanks that what i needed to know, and yes it is tight for space

side pipe?

 

remember the less restrictive you go the higher up to need to rev the motor to make the extra power and get the exhaust into the correct band for power, kind of.

 

if you make the intake more efficient it will work better with the exhaust, getting more out of it. for example, if you add a exhaust you may gain 5hp, if you add a carb it may also add 5ph both separate, but together they make make 12hp.. if you kind of understand where I'm coming from, or that's how i seem to understand. i know you probaly don't have an exhaust system other than the original one which you have to change anyway. so this isn't quite your question and I'm heading further off track with my ramblings....

1.75 is probably as big as you need. More than that will probably just make it noisy.

 

yes, ive got 4-1 extractors with 2'' pipe, a first mufler under front seat and a 4'' outlet cannon at the rear. its farken noisy, thats in a ke70 I'm guessing the s600 is a bit smaller and wont have as far to travel, so the pipe size wont need to be as large.