I could be wrong somewhere in my calculations. Not particularly sure. What rev limits and tyre sizes were you guys using? My revlimit was around 8500rpm and tyre diameter around 650mm.

I may have also introduced some error because I made some corrections I thought necessary when converting RPM back to KM/HR. I am assuming TN is the effective gear ratio used to calculate revs from km/hr. I could be wrong. I don't know how it gets your tyre diameter unless that is a parameter input into the software. So yeah, god knows, could be way off. Next time I talk to the tuner I'll get him to do me a print out with km/hr. Actually, will go downstairs and see if I have one

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Originally posted by MR2Vaeth

I was curious, so I made a comparative graph. Toten, I wanted to map yours onto this graph too but can't see the Y-axis of your graph very clearly. Also, I don't know what RPM corresponds to what KPH on your X-axis. (numbers obtained from the "Australian Dyno Registry" thread in the "General MR2" sub-forum):

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Ha. Another surok fail. This bloke must have done something quite legendary. Maybe i'll see him at the next meet??

His is NA

Not a bad result Brendan. Looks like you're having trouble holding 18psi, as peak was around 16psi from the looks of it. With 214rwkw @ 16psi, I'd estimate somewhere around the 225 rwkw mark with your target 18psi (around 235 with 20psi), which is pretty much on the money. I think it'd respond well to another degree of ignition timing, but I suspect you'll be cutting it too close (might detonate). I might have a closer look at the meet to see what the problem could be. I had boost holding issues on my K1 too, which was due to the BOV.

I think your calculations are off Tot. Maybe try quickly plot my old 312 graph Brendan. This one went up to the 8500rpm rev cut.



For your reference, here's one of my old K1 graphs.

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Originally posted by MR2QIK

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Originally posted by MR2Vaeth

How'd your car catch on fire man?

Yeah I'll be at the next week. I get back from holiday just 2 days before the next meet so I should still be in holiday mood.

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Had my alarm replaced, so when the sparkie re-connected my battery (while I was working from home) he faced one of the terminals the wrong way. Half my fault for not double checking, because when the spare tyre went back in & bolted down, it was touching the terminal. True to form, it didn't short out till I was on the M4 in traffic. I pretty much knew where the problem was, but when I opened the frunk & reached for the bolt, I got a nasty shock with some nice sparks flying everywhere [B)] All sorted though, no damage done other than the bolt that ties down the spare is melted, snapped & resembles chalk [8)] Usually not an issue, but I recently installed a taller/bigger battery than usual.

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Man I had the same problem, well similar on my NA for MONTHS. Car would randomly just turn off for no apparent reason. One day I had the spare out of the car and noticed large chunks out of the spare rim. Basically the terminal was shorting tot he spare rim and cutting out. Fit of rubber over the battery and the problem is now solved :)

Jay, my turbo seems to be hitting a peak of 18 - 18.5 psi at max boost, then dying down to just over 15 psi at the end. Would be nice if it could hold boost all the way to the end of the rev range, but that might be a limitation of my engine rather than the car (i.e. cams). I think that there is probably maybe 10 or so kilowatts left in the engine if I really wanted to extract every last kw from it, but nah...after all the headache I've gone through to get here I just want to enjoy the car for a bit.

I'll have the new dynosheets from Jay and James up later today. Gotta do some real work first. :)

I think my calcs are right. Tyre diameter = 0.65m = 0.00065km
say revs = 8500 rpm = 8500x60 revs per hour

Effective gear ratio = 4.28 (final drive) x 0.918 (fourth gear ratio)

Therefore speed = (8500 x 60 x 0.00065 x 3.14)/4.28x0.918 = ~264

A graph of speed vs power isn't an accurate comparison of spool or power delivery. You would need same gear ratios and tyre heights to get an accurate indication. Perhaps get tyre sizes and convert all the other graphs to RPM.

Speaking of RPM, I don't know what formula the dyno used to convert road speed to RPM on my graph. What is the TN function on the bottom of the graph. Is that the effective transmission ratio that the dyno software uses for the calculation? Where are tyre heights etc input?

Can someone who might speak often with a dyno dynamics operator find out what algorithm the software uses for the calculation so I can get a proper indication of actual RPM? I know that the car was redling at 8500rpm, not 7600-7700 like the graph is indicating, so I think its out about 10%, which would make sense if TN is set at 3.54 when it should be 3.92

The previous calculations I made assumed the revs on graph were actually 10% higher.

Can I get tyre sizes and any information on non standard gearing (and what are the NA gear ratios?) for the cars in question (tyres on the car whilst it was on the dyno). I can do calcs to find revs for a better comparison.

I think my calcs are accurate. From memory, I am pretty sure my car did in excess of 240km/hr in 4th.

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Originally posted by -Totenkopf-


Perhaps get tyre sizes and convert all the other graphs to RPM.

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Easily done if I can get the data from the others.

Bionikal, no wonder you had so much bad luck with your build, you used up all the good luck on that battery issue. I've heard of a few MR2 owners returning to their cars with a hole burnt through the bonnet from similar incidents.

Brendan, your boost issue wouldn't be related to the long motor itself, more likely the turbo system. Possibly the BOV, or even the K1. What boost controller are you using? Fair enough if you're content now, but that's something I'd want to rectify at some point. 15psi isn't even close to pushing your motor. I was aiming for 20psi with that turbo. Don't feel down though, I'm sure the car would feel quite strong at this point.

James, I'd be interested in seeing the correct numbers too. The more I think about it, the X-axis doesn't seem to add up. There would be a few variables involved, but my general thoughts on the matter are that dyno operators prefer to spend more time on the actual task of tuning rather than calibrating the X-axis to perfection, hence the discrepancies.

What's I'd like for the track is the bottom range that my car has now, the mid-range that Jay's K1 used to have, and the high-range that Dylan has. Is that so much to ask: