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4age Exhaust
Bass1st - 19/3/10 at 08:06 PM

Had my MK up at Northampton Motorsports today and it appears the silencer on my car is from a 600 or 750 cc motorbike!! It is restricting the exhuast gas and limiting the BHP from about 5500 revs. Anyone got a spare silencer or complete system for a 4age?

tul214 - 19/3/10 at 08:12 PM

Can't really help with the silencer but interested to know how your your power results.

Mark

SPYDER - 19/3/10 at 08:53 PM

How did they diagnose this problem?
Did they try a power run with a different silencer or without a silencer at all?
You could try a race type can from a similar size bike or maybe a standard can from a ZX9 or similar.
The race can will be very noisy though and will scupper the chances of a trackday.
There are loads of bike cans available on ebay but your choice could be limited by noise levels.
We have a standard ZX9 can on our Phoenix. Bike engined admittedly, but it is Titanium.
What power output are you expecting from your 4AGE?

Geoff.

Bass1st - 19/3/10 at 10:04 PM

They diagnosed the issue by looking at where the exhaust started to glow. Usually you would expect the glow to be at the manifold, however it was glowing just in front of the silencer. When we looked in the silencer itself the radius of the exhaust is very small. 1600 engine trying to breath through a 600cc exhaust! Engine runs perfectly up to about 5500/6000 revs then all the engine just goes flat. I would expect between 130 and 140 BHP with the 45 DHLA's I am running.

Bass1st - 19/3/10 at 10:09 PM

... best we got was 117bhp @ 5800 RPM!

bimbleuk - 20/3/10 at 05:27 AM

What is the peak power ofthe 600cc bike engine and at what RPM does it achieve this. If its over 10KRPM on the bike and you're only reving to 6KRPM then the flow won't be that different to my thinking.

Having said that the exhaust colouration can be a good guide to restrictions.

On the Striker the standard exhaust is 1.9" ID and that's fine for up to say almost 200BHP. However my 4AGE was supercharged to 270BHP and though the exhaust was flowing still it turned blue from end to end!

I changed to a 2.5" ID system and silencer and it didn't discolour. 2.25" would have been enough but I didn't have the option at the time.

[Edited on 20-3-10 by bimbleuk]

[Edited on 20-3-10 by bimbleuk]

blockhead_rich - 20/3/10 at 08:58 AM

With my old 4age I got 151 bhp @ the flywheel. This was at 7349 rpm. It had standandard internals but my own inlet manifold and GSXR T/B's and larger injectors. Can't remember what diameter the exhaust is.

I'm just up-graduing to the 20v ST engine. Anyone know what bhp I can expect from that?
Rich

Bass1st - 20/3/10 at 03:06 PM

Took the exhaust off and its is from a Suzuki GSXR - can't tell if its a 600, 750 or 1000cc. Will buy a cheap race can from ebay to see if makes a difference!

bimbleuk - 20/3/10 at 06:38 PM

quote:
Originally posted by blockhead_rich
With my old 4age I got 151 bhp @ the flywheel. This was at 7349 rpm. It had standandard internals but my own inlet manifold and GSXR T/B's and larger injectors. Can't remember what diameter the exhaust is.

I'm just up-graduing to the 20v ST engine. Anyone know what bhp I can expect from that?
Rich


If the dyno reads anything like the one I use which also happens to be the RAW Engineering preferred dyno then you'd be lucky to get 150 BHP out of a standard Silvertop. Blacktops do usually make low 150s in standard trim on that dyno.

My Silvertop with some head flowing and a mild exhaust cam made 162BHP.

Bass1st - 28/3/10 at 07:51 PM

Popped a race can on the car today. £50 off ebay. Makes one hell of a difference on power and noise It is now popping on over run so need to sort my fuelling out.