Big bore SS exhaust for racing

[Marlow Sud]

Hi All,
I was going to put my exhaust back on tonight but there is a problem.
The exhaust ports are enlarged and the exhaust manifold is not.

If you look carefully the gasket has been enlarged inside to match the port profile.

I need a complete new SS exhaust. This one is choking the engine.
Any advice much appreciated.
All the best
Simon

[Jube]

Taking Shrew a little while to find this thread!

[Marlow Sud]

Hope Shrew can help me in short order as the car is booked on the rolling road on 24th March!
I can't have it snorting through these pipes!

Brgds
Simon

[PETROLHEAD]

Sorry chaps,

I dont like to blow my own trumpet too much, but as there is haste in the mix, I'd better have a look at the diary quick sharp,

But that's gonna be tight!

Which car is this for Simon?

[Marlow Sud]

Hi Shrew,

We have delayed taking the 1.5 SC out racing until it is 100% ready so apologies for the previous hurried message.
We have Simpson Racing exhausts just 10 miles away from us so I took the car over there. Matt Simpson took a shine to the Sud and built an exhaust for the car.
I thought I would share the pictures with everyone. Matt sent them this morning.

All the best,
Simon

[Kegsti66]

Very nice Simon, bet it sounds good.

[Marlow Sud]

Hi Keith,
Next we have to get the engine running properly by changing the ignition system back to original Bosch electronic contactless.
Hopefully that will fix it but if not we will then look at the carbs.
I will let you know how it sounds. The car was on song for two laps at Silverstone and was a lot faster than the Sprint for that brief period so we have high hopes.

All the best,
Simon

[Marlow Sud]

Hi Guys,
I was changing the wheels on the Trofeo today and thought I would take a peak at the exhaust system manifold. Thought you might like to see this too. It's equal length pipes with crossover:

image.jpg[/attachment [attachment=0]image.jpg

[KevJTD]

quick question
on the n/s head there is a drive from the rear of the cam, looks like a cable drive of some sort, what is that for?
mechanical rev counter?
not seen one of those on a sud before.

[Marlow Sud]

Hi Kev,
Well spotted. You are correct. It is a mechanical drive for the Rev counter. Tom at BLS was surprised to see it too. It works very well.

All the best
Simon

[Marlow Sud]

1.5 SC performance with new exhaust and std Bosch ignition.

[Veesix75]

That's a good linear graph, good torqueand power at low revs, which I miss in the 1500 due to the cams. It must be a nice car to drive.

I'm no expert (on anything!!) but maha are generally considered to be relatively accurate Dynos according to my local rolling road owner.

As per the comments Bryan has made before regarding his old full race 1800 power, personally I think many dynos are optimistic and people quote some big numbers on smallish engines, and the conservative ones are actually closer to reality. I had an engine dyno'd at 145bhp on one set of well known rollers in the sarf, and on my local maha dyno it was 129bhp. The latter was more like it in reality.

Btw, the comment about the dyno in the south isn't a criticism because the engines were absolutely spot on with every last bhp squeezed from them by the expert chap doing the work.

I'd be very happy with the figures above Simon, and the main thing is that the car is now running spot on and you have a benchmark to use if you make changes. We could visibly see it was quick for the few laps at Silverstone when it came back on power.

[Marlow Sud]

Hi Tim,

This car came with a dyno report showing about 173bhp. The general reaction was - no way!

The next dyno showed 152bhp at 6850rpm with an exhaust with manifold pipes that were restricting flow.

I don't think this dyno report is too far out.

Thanks for your comments.
Brgds
Simon

[Veesix75]

Yep, hopefully you read my words in the same way, this roller figure feels more like it.