5 replies to this topic

[Minitrio]

Hi All,

I have no doubt that this question has been asked a 100 times, but having searched the forum it didn't quite answer my question in its entirety.

I am just about to complete a stage one upgrade to my '89 998 and just have to fit the air filter and RC40 back box. Fortunately I have a few options and combinations and I'm after improved performance with a nice sounding exhaust note without getting an ASBO!

I have already fitted Maniflow Freeflow LCB manifold, Rc40 centre pipe with rear muffler, HIF38 with AAA needle and red Spring connected to a Water heated inlet manifold.

So I have a K&N Cone Filter and a K&N for standard air box, I also have a RC40 centre exit single tailpipe and a RC40 twin DTM centre exit Back boxes.

So my options are:

K&N cone with RC40 single
K&N standard with RC40 single
K&N cone with Twin DTM
K&N standard with Twin DTM

Which would be the best combination?

I appreciate that it's probably down to personal preference and a rolling road session would show best performance results for all options, I just want to know what people thought or possibly have already tried and tested.

Thanks for reading

Edited by Minitrio, 13 December 2015 - 09:02 PM.

[Anthony30]

AAA is usually far too rich, try AAU. Maniflow freeflow manifold with Maniflow 1.75'' single box. Twin box is too quiet, unless you drive on the motorway a lot. IMO of course.   Don't MED sell an air filter set-up for a single HS4 carb? I know they do for twin HS2 carbs.

 

[kezzkitkat]

I have such a dirty mind that title lol
The twin dtm I would say no on a small bore
I would go for the k and n cone and single rc40
As above I would change the needle over to

[Cooperman]

Forget the DTM as it will simply lose you a few bhp. For best power it is a very poor design.

The RC 40 is an excellent system and the choice of cone or standard K & N will probably not make a lot of difference. Best to use a stub-stack inside the K & N filter which improves airflow into the carb a bit.

It is also a good idea to gas flow the carb a bit as outlined in Vizard's book 'Tuning the A-Series Engine'. 

[Minitrio]

Cheers Guys.

I will stick the RC40 single on and play with the air filters, which I guess would be down to the induction noise.

Will run with the AAA for a few weeks, then take it for a roller road session and go from there

[jaydee]

Suck and blow query

I was expecting some hot discussion 

Then another thread about mini exhausts 

This is fake advertising man