Hi,

quick update in that I just did a powerdyn run on the car (still with incorrect renix and overfueling) and it doesn't look too bad, bit of extra power due to reduced weight (not much fuel) and good hot weather but overall looks pretty good.



Thanks to Chris C for giving me a couple pointers on what wav types the software likes

I'd actually say the 'extra power' is due to Powerdyn, if Chris' car was anything to go by... Still a very cool toy

cheers

James

I found where the extra powerz were leaking into mine.... Operator error I believe its called

Jason, you gonna put a picture size up we can see

Foggy, the extra power in mine I reckon was down to an error in the car weight, I still had it set to the same as Jani's 360... basically 10% over what it should be I think.

Next time I'm at the scrappy, I'll get Fake and me on the weigh bridge, be able to get the total and both axle weights then.

Ohh, Jason, another useful thing is to keep all the old wavs you record, with a detail of date and why state teh car is in. That way if you ever change your car profile (i.e. refine it a bit) you can still do straight comparisons between the old runs by re processing them.

Chris_C wrote:Next time I'm at the scrappy, I'll get Fake and me on the weigh bridge, be able to get the total and both axle weights then.
.

bit dangerous that isn't it Chris ?

the next thing you will see is the crane swinging over and the scrap yard owner paying you £40.00

I believe the th at the beginning of the file name was for thumbnail

yeah, I was in a massive hurry to get to work so I must have put the wrong link in. Will sort it soon

edit: pic now sorted (click it for full size)

Torque is pretty accurate, but I'm surprised that peak power is up that much - stock is 101.

A bit of a giveaway might be that BHP and torque curves should always cross at 5252 rpm....hmm!

cheers

James

Yeah, the numbers for Powerdyn are always complete rubbish, but the shape of the curve looks good. Have to say though that the peak torque should be a little higher. That's probably the combination of a carb, a carb Renix timing and an A-cam, completel mixed bag.

120lbft sounds roughly right to me...perhaps 125, but no more than that, I wouldn't think. B230s make around 140-145.

cheers

James

Sorry, meant a little higher up the rev range, numbers, as I say are irrelevent.

foggyjames wrote:Torque is pretty accurate, but I'm surprised that peak power is up that much - stock is 101.

A bit of a giveaway might be that BHP and torque curves should always cross at 5252 rpm....hmm!

cheers

James

Well, curves should cross in same place as only torque is 'measured' in any dyno, HP is only math. Torque X RPM / 5252 when using american units

Numbers are as much of truth as operator has made them to look truth, set gearbox losses to 0% and you see what is measured from velocity change over time, if your mass, weather etc. parameters are set correctly you have valid data. Always make sure you use same place and take average of pulls to both directions and you are quite close already.

My car's weight is bit high as car was not near empty and I'm not exactly featherweight either

If comparing results to others it should be done on same time on same road etc. so that is not possible and I would say it is useless for such, it is useful mostly to find what range power is and if you do changes to engine or loose weight (or car's weight ) you can get bit of idea what that change is going to effect.

There is no rolling road that gives you any better results, their advantage is that there is less enviromental disturbance, but we have seen power difference of 80hp from very same car and very same day in two different rolling roads. Only engine dyno can tell you how much power you really do have.

It is important to understand limitations of tools and use them properly for what they are made to

So if you are checking what something changes in car use always same measurement method, if you are using rolling road use same rolling road and same operator preferrably, etc. This is something that is rather badly understood by our(finnish) racing folks, too many of them thinks that rolling road will tell real power.

Oh yes, by calculating acceleration of my car we have come to conclusion that it should have around 109hp from wheels, what it is in engine, nobody knows.

I totally agree, my only use for the information is to serve as a comparison between carbs and other engine tweaks (and if work allows me enough time, some weight reduction of my own ). I will be using the same stretch of road and hope that comparisons shouldn't be too bad.

Just to drag this post back to the present, I have sorted out lots of little bits and bobs and the car is running well (carb problems aside), I read earlier in the thread that a 531 head from a 230 bolts straight onto a b200k. Just wondering if this is actually true, and if so what benefits would it give?

Cheers

Jason

Jason B wrote:Just to drag this post back to the present, I have sorted out lots of little bits and bobs and the car is running well (carb problems aside), I read earlier in the thread that a 531 head from a 230 bolts straight onto a b200k. Just wondering if this is actually true, and if so what benefits would it give?

Cheers

Jason

It flows bit better, but there is no point getting one if you are not going to HUGE power, they cost quite a bit, at least in here, those are really expensive, costs 10 times more than 530 which you can make to flow as much as stock 531 without too big trouble, of course you can make 531 to flow bit more than that