4AGE budget cam install and tuning

[Lauren]

Okay done the cam timing as per John's.

Mine was originally set at -3 inlet and -4 exhaust.

Now set it to -5 inlet and -7 exhaust.

Is dead easy to do on my HKS cam wheels.

Results are perhaps somewhat qualitative, but the car undoubtedly goes well revving strongly to the limiter as one might expect with the spec of cams (the power range is to 8300rpm).

All good so far, I shall drive it and see how I go.



They go round too:

[FossMan]

Just got my car back from Circuit Motors at Castle Combe where the car was Rolling Road tuned for HKS cams (256/8.1).

They were previously installed and set up with assistance from vashy. I felt the car was quick high up the rev range but starting was poor, it ran rich and idle was very lumpy.

It now idles very smoothly and is a lot easier to drive. So definitely worth having your car on a rolling road if you are thinking of getting cams. Here's the final result - 146.4bhp @ 7,326rpm Very happy with the figures.



I haven't got the exact setup in terms of degrees advance/retard. I don't want to go out and look at the pulleys in this horrible weather but I will update the post if its of any use to others.

The car also has the usual filter/exhaust as well as porting to the cylinder head.

Chris

[LimeyMk1]

Good result Chris.

[jimi]

Not trying to be funny, but 113.8 measured at the wheels and 146.4 calculated at the flywheel.
That means they are allowing 28.6% for transmission/tyre losses
That's pretty hefty, it's normally more like 17% for a Fwd car and a MK1 basically has a fwd drive engine/gearbox mounted in the middle or am I missing something ?

[jon_st205]

IME yes that is a little excessive, especially with a C52. However a genuine 113 @ the wheels is pretty respectable no matter what

[Lauren]

Not trying to be funny, but 113.8 measured at the wheels and 146.4 calculated at the flywheel.
That means they are allowing 28.6% for transmission/tyre losses
That's pretty hefty, it's normally more like 17% for a Fwd car and a MK1 basically has a fwd drive engine/gearbox mounted in the middle or am I missing something ?

That's par for the course for AW11's. I had 186 at the flywheel and something like 126bhp at the wheels. Friends of mine with similar setups showed the same difference over a number of rolling roads.

[jimi]

However a genuine 113 @ the wheels is pretty respectable no matter what

I've no argument with the measured figure and as you say a very good figure.
I just can't agree with the guess, 28.6% losses is excessive no matter what the combination. Even 17% is high IMHO, seems to be common to accept around 15% for Fwd and 2-3% higher for Front Engine/rwd as the diff has to turn the transmission 90°.
I know flywheel figures are always controversial, the only time I'd believe a flywheel figure is if it was measured on an engine dyno

[FossMan]

the only time I'd believe a flywheel figure is if it was measured on an engine dyno

Everyone that tunes their engine uses RR figures as a benchmark.

Is there a rule on car forums I don't know about where someone has to give the "transmission losses" or "rolling roads over-read" reply instantly?

Anyway. I'm inclined to believe my engine tuner due to his experience and facilities (1000bhp 4WD rolling road).

The car has been on the RR previously. M-tech in Wiltshire gave me a figure of 131bhp @ approx 6,700rpm before the cams were fitted. On that day there were bog standard mk1s making between 115 and 125bhp. The cams and pulleys appear to have given me 15bhp and moved the power band up the rev range, which is exactly what they're supposed to do.

[jon_st205]

Heh @ 126 wheels to 186 fly!

[jimi]

Everyone that tunes their engine uses RR figures as a benchmark.

I have no argument with that, or that your engine makes good power but there is no getting away from the FACT that on a RR the wheel figures are a measured quantity, flywheel figures are "estimated"

[PW@Woodsport]

I agree with Jimi, 28.6% loss seems very high for a C52, i would have thought more like 15%-16%

[SuperRedMR2]

113 at the wheels is somewhat disappointing no offence as my previous engine put out 107 at the wheels on standard cams...

Did you change your ecu, buy uprated valve springs and buy an adjustable FPR?

[FossMan]

@superred. Nope.I listed the spec in my post.

M tech didn't provide the whp figure so I can't do a comparison there.

[stenky]

how about bigger valves? volume per minute can be adjusted in many ways. as any silly imperial measurements, there is plenty of silty furlongs per light year lights

*lift
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*surface

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