Mi16 Inlet Only Catcam Rolling Road Results

[jackherer 543]

I've recently fitted a cylinder head that had been reconditioned by QEP and an inlet only Cat cam to a friends 205 Mi16. On saturday we took it to the PSOOC rolling road day at Track'n'Road Powerformance to see what difference it had made.

 

 

Peak power was 158.5bhp which is pretty disappointing really...

[dee205 3]

That seems way off does it not? Others have got over 170 haven't they.

Is the cam timing set right? There looks to be a dip in the mid range looking at he graph or is that normal?

 

 

Damien

[jackherer 543]

its got a number 4 pulley on the inlet and a 2 on the exhaust. I think the dip there is normal for an Mi16?

 

I've noticed the join between the back box and centre pipe is slightly sooty so it must be blowing a bit, although it sounds fine. Is it likely to lose 10+bhp to a slight exhaust blow?

[dee205 3]

I can't imagine loosing that much power with a blow out well down the system. Maybe if it was at the manifold or downpipe then the pressure loss may do some harm to the flow.

 

Damien

[jackherer 543]

in this thread d-9 doesn't think that his Mi16 with inlet only cat cam feels any faster than standard (even after advancing his inlet cam timing and restoring his low end pull) and John B seems happy with 177bhp but if you look at his graph he got 135bhp at the wheels which realistically is about 160bhp at the flywheel (My friends engine made about 132 at the wheels).

[Alastairh 47]

Kate has seen good gains out inlet only cam with before and after rolling sessions.

[pug_ham 240 3 Cars]

That does seem low, I would've hoped for a better result.

 

A blowing exhaust that far away from the manifold wouldn't cause that much loss imo.

 

I was thinking about getting one for the Mi I'll be fitting in the new year before I have it mapped on MP3.1 but now...

Kate has seen good gains out inlet only cam with before and after rolling sessions.

Kates is a little different though with TB's & Emerald so it will make a difference.

 

Graham.

[petert 550]

Low compression? What's your cranking pressure readings?

[maxi 36 1 Cars]

I would say there is definately something wrong there....... The CATCAMS do work very well in all their forms, although I would say that you are never going to see huge gains from minor profile difference.

 

It should see 170BHP with a shortened inlet and I doubt you will lose any power due to the pipe blow.

 

Maxi

[maxi 36 1 Cars]

How does the car drive? Does it feel s hit?

 

Maxi

[Bam 0]

what's the power before changing cam?

[jackherer 543]

Peter: I cant find my compression tester so I don't know yet, I wanted to test it before putting it on the rollers...

 

Maxi: It drives OK, doesn't seem significantly faster than my 205 with a standard Mi16, it might be a little bit better but its hard to say. The gearbox I just fitted turned out to have knackered 2nd and 3rd gear synchros so its impossible to accellerate smoothly through the gears which makes direct comparison hard.

 

Bam: No idea what the power was beforehand, the cars never been on the rollers before and the head/cam were fitted due to some bent valves so there wasn't a chance to test it beforehand.

 

On the same day at the same rollers a standard 1.9 8v made 130bhp for comparison. Unfortunately the only other Mi16 there was running very lean and so only made 147bhp.

[Trick 1]

Sorry to hijack thread - sort of related..

 

Interesing - ive just had a RR session with my freshly rebuilt MI16 with std cams (alloy block version) with twin 45 webers.

Im getting a hugely disappointing 161 bhp - the RR kept it in because it wasnt happy with the setup. he Said, "something very strange is going on here, ive set up loads of MI16's on carbs - and this one wont setup" - at first i thought it may be the fuel pump as ive had fuel issues - but this is fine - just a noisey pump!

 

ive made 1bhp with carbs -

 

They are still working on it, going to check compression & cam timing.

All of this i would expect to be spot on as its just been rebuilt?

 

Should i be expecting nearer the 170-180 bracket?

 

I dread the bill.

Edited November 22, 2006 by Trick

[cybernck 400 1 Cars]

ive made 1bhp with carbs

what sort of statement is that?

 

have you done the "before" run?

 

maybe the power would be 150 bhp (even after rebuild) without carbs, if you see what i mean.

[Trick 1]

comparing it against standard.

 

Yes, im assuming the rebuild would have given me a standard figure - nothing else to gauge it on.

[John_B 11]

and John B seems happy with 177bhp but if you look at his graph he got 135bhp at the wheels which realistically is about 160bhp at the flywheel

 

LOL - There's absolutely no way that mine is putting out 160bhp, but I bow to your expertise seeing as you've never even seen the car let alone driven it.

 

When I get a few jobs sorted on mine I'll be going back on the rollers to see what it makes. You're welcome to come along with a car you know the output of and compare. Only costs £15.

[jackherer 543]

I really wanted to avoid getting into that debate, thats not what this thread is about.

 

177-135 = 42BHP losses you think thats possible?

 

my friends car made 132 at the wheels, only three less than yours, so in your opinion did my friends car make IRO 175BHP?

 

IMO 177BHP at the flywheel equates to nearly 150 at the wheels.

 

I'm not saying your car isn't faster than a standard Mi16, it may well be for all I know. It doesnt take a high peak figure to make a car faster though, the shape of the curve is whats important...

 

The only reason I quoted your results is because I was looking for definitve proof that the catcam improves things and I'm afraid your figures dont prove anything to me.

[taffycrook 2]

I agree its not about about RR outputs but this dyno is well known to me and gives very repeatable results.

I could go into how and why the figures differ and why the losses are not 42 bhp etc

But its not worth it, just to add I have run over 15 std ish mi16's on these rollers and none have made more than 168 BHP

My mondeo is a 1.8 book figure 125 bhp and we used this as a before after calibration test as the unit was balanced by vibration free and the figures were 124.5 before cal and 125.5 after. The car has been run 5-6 times through the year and the variation is less than 1%.

 

Not conclusive proof by any means but it proves that the dyno gives results that can be compared to other cars that have run on this dyno. To that end a healthy mi16 on 45's made 181 mine made 185 and Johnb's with std mi16 inj made 177 with a inlet cam.

 

I am willing to pay for back to back tests. Or a dyno day to prove that certain dynos are relaible if used correctly.

[jackherer 543]

My friend is working away from home at the moment so I still haven't been able to compression test his car but I have learnt that he replaced the dizzy cap and arm which has solved some difficult cold starting that I wasn't aware of - maybe this will have improved things? Its looking like it will be getting a rebuilt bottom end soon anyway, so it should have everything in place for the cam to do its thing hopefully.

 

Taffycrook: comparisons to other mi16s mean a lot more to me than absolute figures, thanks for those