Race Engine Forum UK

Hi All,

Inspired a bit by URBANCAMO's thread regarding trying out different length ram pipes ( viewtopic.php?f=5&t=2631&start=105 ), I have decided to have a go myself on my Fiat X1/9 1500cc SOHC. (Attached is thread showing the car)

viewtopic.php?f=4&t=2161&hilit=dcnf+comparison

The reason for not doing it before, has largely been down to the fact that the existing ram pipes sit close to a bulkhead, which leaves just enough room to fit a set of air filters without restriction. I am planning on removing and redesigning the said bulkhead, and so free up some space.

Does anyone have knowledge of a ball park figure for the right induction length for these motors? I have used some "calculators" available on the internet which give an approx between 13" and 17" from the back of the valve to the end of the ram pipe.

Second question. If anyone has tried this type of testing on this motor, did they get good or noticeable results?

For info the motor currently puts out 144 bhp at 7,300 and 115 lbft at 5,400 rpm and current induction length is approx 10"

Regards, James

What's the length of the primary pipes on your ex manifold James?

G

Hi Guy,

They are approx. 28" long give or take half an inch, and 1.5" OD, running into 13" secondary pipes at 1.75" OD, then a 2.25" OD final pipe. Which is (about) the same as Steve Sharpe’s Inj. SOHC, as he kindly supplied the dimensions to you, and you kindly passed them to me.

Regards,

James

with primary pipes of that length you could run any rampipe length you want. I'd be tempted to keep it quite short - an inch or two - lengthening will likely tend to move the torque down the rpm band.

G

Hi Guy,

OK, many thanks for your reply, that is interesting. I will probably carry on to prove this out. I will be sure to post my findings whatever the result.

Regards, James