mobi
Wow Rob!!
You have fulfilled the promise of this car. The modification path is quality and it definitely shows in the results.

You definitely need bigger stickier rubber to hook up that much grunt, or maybe you enjoy all the tyre squealing fun that 350+RWKW can provide.

Great work, enjoy the car and be safe, with this much power the MR2 platform can be a handful....

Hey mobi, it's been a while! I hope you've been enjoying your sdub as much as I've been enjoying mine.

Wider rims and tyres at the back would be nice, but my rims are very rare and I couldn't be too picky about widths (I love the rims so I never want to compromise by changing them...unless I get them rebarrelled some day). Anyway, I do enjoy the tyre squealing, up to the point where it's fun but not excessive. The behaviour that I described when mashing the throttle to the floor and holding it there, is something that I will avoid at all costs in normal circumstances, but I had to try it at least once haha. Normally when I squeeze the throttle on more gradually, there is a much more suitable and fun amount of wheelspin.
 

rikkir
With great power comes great responsibility?

That's for sure. As mobi said, it's a handful!

WIDEMR
What do you think of the racerx cam sensor on the engine mount? hows it been working, compared to the dizzy side one you had?

The RacerX cam sensor in the dizzy location was going well at first, but I soon realised that it was poorly designed, with oil leak problems and excessive wear due to the shaft design. When I emailed RacerX about the problem, they agreed that it was a flawed design, which is why they sent me their newer kit (for the engine mount on the other side) free of charge.
The new cam sensor kit on the engine mount is working perfectly now, but I was unlucky and had to overcome initial teething issues with it too. The kit comes with a cam reset disc with one small slot cut out of it, instead of a single tooth, and that disc mounts on the exhaust cam sprocket with a spacer in between. The hall effect cam sensor is aimed at the outer face of the disc, rather than the edge of it. The problem is that a tiny imperfection in the spacer will be amplified at the outer face of the disc, causing the air gap to vary in front of the sensor. In my case, it varied enough to cause problems. I solved the problem by modifying the cam reset disc (with a grinder) to have 1 tooth instead of 1 slot, and I made the tooth bigger to ensure that it would be reliably detected. Then, by having a tooth instead of a slot, I was able to adjust the air gap with the tooth in front of the sensor, and any deviation around the rest of the disc would be ignored by the sensor.
RacerX said that they use a slot instead of a tooth simply because it's easier to manufacture, which is what I expected.
 
*EDIT* Here are photos of the new cam sensor kit, before and after I modified the disc to have 1 big tooth instead of 1 small slot.
Before:

After:

 
 

WIDEMR
Also im sure i read you were having issues with the 60-2 wheel, was this the crank? what issues were you having.

Yes the crank. At about 6500+ RPM, my ECU wasn't getting reliable pulses from the RacerX 60-2 crank hall effect sensor. Basically the teeth on the RacerX 60-2 crank trigger are very small (in degrees), so after the signal was filtered by the ECU some of the teeth/pulses would disappear altogether. This could've been fixed with a firmware update, but instead I chose to design my own 36-1 trigger wheel and had it laser cut locally. I had fun doing that anyway, and I was able to design it with teeth of a suitable width etc, and be totally confident of solving the problem straight away. Also, 36 teeth is plenty, 60 is more than enough.

Today I received the Dandism floor mats that I ordered on eBay last week, and they're in great condition!
Finally I can get rid of my crap aftermarket floor mats, as I should have done long ago.
 

 

 

Yesterday a mate of mine had his SW20 turbo tuned on the same dyno as my car.
When I was talking to him about his dyno graph (which I won't post here), I happened to notice something interesting compared to my dyno graph. Mine is shown again below.
 

 
Notice how the horizontal axis shows both the RPM and the km/h. The dyno calculates the RPM very accurately using one of the spark outputs from the ECU, while the km/h is calculated from the diameter and speed of the dyno rollers.
 
On my mate's graph, his RPM vs km/h matched perfectly with mine at low RPM, up to about 4000rpm (where the boost really starts to increase rapidly on mine).
However, at 5140rpm my graph shows 130km/h but his shows about 140km/h, and at about 7000rpm mine shows 180km/h but his shows 200km/h.
 
This means that when my car was on the dyno for the E85 tune, the tyres must have been slipping significantly against the rollers, all the way from 4000rpm to redline. There is a km/h discrepancy of about 10% at 7000rpm, which is quite a lot of wheelspin on the rollers, therefore my dyno graph would have shown an even higher power figure if there was no wheelspin!
 
My tyres can't even put all the power to the ground on the street either, so it certainly doesn't bother me, I just thought it was a bit amusing.

Eric
So that mean you would have been arround 370-380kw?

Yep!

Eric
I don't know how you drive somthing like that lol

With such a high power/weight ratio, I honestly can't just jump in the car and drive it with my brain in autopilot mode like a 'normal' car (unless I only intend to cruise around mostly off boost...the car is easy to drive in that case).
Normally before I set off in this car, I have to get myself into the right mood, in the zone.
If I apply anything over about 40% throttle, I have to be completely focused and prepared for the tyres to break loose if I apply more throttle. I don't think it will ever stop feeling frighteningly fast and exhilarating.

Congratulations!   Great development and obviously done thoroughly.Thanks  for your write-up.
Interestingly I was only talking to Steve a few days ago about tyre slip on chassis dynos. Can be very difficult.
Most E153s are the same final drive ratio 4.285 in the MR2.
Im keen for a passenger ride when you come up to Qld !!      Cheers.

robk


My goal is to have at least 250kW at the wheels, maybe up to 280kW depending on how I do things.

 
I think you reached that goal you set back in 2010...

Eric
If you're ever up in Queensland, can you take me for a spin? a fellow black mr2 owners dream :P

Falcon
Im keen for a passenger ride when you come up to Qld!!

Is there any chance that either of you can travel down to the 30th Anniversary event in Sydney on the 28th? That might be your only chance for a passenger ride.