Decent Performance Mods

[banzaijoe]

Hi everybody,

I hope you're all keeping up to date every month on the modifications I'm carrying out to Project Aygo. If not, you're really missing out on some great information.

The latest issue contains preliminary details of the supercharger conversion we're carrying out in conjunction with Rotrex dealer TTS Performance in Silverstone. The upshot is, the car's now running 108bhp at the wheels, or around 130bhp at the flywheel - almost double the power. We've just got a few tweaks to make to the piggyback fuel computer that is controlling the fourth injector but other than that it's running exceptionally well. This car will surprise everybody with how fast it is, and it will be available soon as a complete performance package for anyone wanting decent grunt from their Aygo/C1/107, and all the other 1KR-FE engined relatives.

Regards,

Joe Clifford

Editor

Banzai Magazine

[Yaris SR Kid]

Sounds sweet, have been reading about it amazing achievement from such small car

[PaulT]

Thanks for the update, Joe. Sounds like a really good job B)

My bad for not reading the mag. Must get a copy asap :D

Paul.

[banzaijoe]

Drove the Aygo properly a few days ago, and even with a few remaining fuelling issues I couldn't resist a few 0-60s. Can't quite remember what the factory figure is supposed to be but it's somewhere in the region of 14-15sec. My new Rotrex supercharged Aygo now does it in around 8.5sec two up. That should drop a few more tenths at least with only me in the car. Only one gearchange is needed as it reaches 65mph in second, then goes on to 90mph in third! How long geared is that?!

[PaulT]

Is this car going to make it to Snetterton? I'd really like to see it, just booked the Soarer in for the track today.

I need to know whether I should use the Aygo or the Soarer for next year's Toyota Sprint Series? Maybe you can help me decide :D

Is there a LSD which will fit on the Aygo? So many questions!

Also, regarding the performance, the old Yaris T Sport weighed about 1000kg, had 105bhp and could do 0-60 in 9sec. I would think you could do quite a lot better in a car weighing 200kg less and with the best part of 130bhp

Paul.

[kenl]

Very interesting but...

Are the clutch and gearbox likely to last long with this conversion?

I would also say that the brakes are nowhere good enough when standard to handle the pace of this upgrade.

[banzaijoe]

I'm hoping to be able to pinch the Aygo from TTS for a few days for our track day on the 7th. But that's assuming that the fuelling, which is still being fine-tuned, will be safe enough to cope with sustained high revs.

I also hope to be entering the Sprint Series in the Aygo. If you're deciding on which category, then I definitely recommend going for Class B with your Aygo. There are fewer entrants in this category, and therefore more chance of a podium finish. Personally, I hope to whip Pete from Fensport in his Glanza.

Not sure yet if there's a suitable LSD for the Aygo - I will investigate that. Though, to be honest, due to the nature of the supercharger's linear delivery, I didn't experience much of a problem with torque steer on my test.

I fully expect to be able to achieve low 8sec or late 7sec 0-60 times in the Aygo when it's fully set up and with just myself in the car. The 8.5sec figure I posted was not definitive - Richard from TTS and I just couldn't resist giving it a go!

As for the clutch and gearbox, they're currently behaving impeccably. Once again, the linear nature of the supercharger's power delivery is kind to these parts. Drive the car gently and you honestly cannot tell that there is anything different under the bonnet (well, apart from the whooshing noises and blow-off valve). Toyota has over-engineered these items, just like usual, and they're certainly tougher than you'd imagine. For example, the standard clutch has to be capable of hillstarts four-up without wilting. So asking it to handle extra power at the top end is not unreasonable.

Finally, on the braking side, that is something I am currently investigating. The standard setup is not in any way dangerous, though I admit it may not be up to numerous high-speed stops. I would imagine that better brake fluid, braided lines and different pads will make a world of difference on their own.

[PaulT]

Not sure yet if there's a suitable LSD for the Aygo - I will investigate that. Though, to be honest, due to the nature of the supercharger's linear delivery, I didn't experience much of a problem with torque steer on my test.

I hadn't thought about torque steer, but was thinking there are three main improvements you might get from a torsen diff. It will stop one wheel spinning up when accelerating hard off the line; it will cause the car to keep power on the outside front wheel in a corner whereas the open diff will let the inside wheel spin up and lose traction; and if you choose the right gearing you may be able to get shorter gear ratios which will help get to top speed faster.

Out of those, it is the cornering improvement which is most interesting to me. However, there is a downside and that is the lsd might stop the Aygo's EBD electronics from working as well on variable road surfaces.

As for the clutch and gearbox, they're currently behaving impeccably. Once again, the linear nature of the supercharger's power delivery is kind to these parts. Drive the car gently and you honestly cannot tell that there is anything different under the bonnet (well, apart from the whooshing noises and blow-off valve). Toyota has over-engineered these items, just like usual, and they're certainly tougher than you'd imagine. For example, the standard clutch has to be capable of hillstarts four-up without wilting. So asking it to handle extra power at the top end is not unreasonable.

I wondered why you went for a supercharger instead of a turbo, but I guess it makes sense to keep the load off the engine at lower revs where it is most vulnerable. Do you know how much power this charger takes to drive it?

The stock clutch is not bad, but it struggles reversing from standstill up a steep hill. Reverse gear is quite a bit longer than first, though.

Finally, on the braking side, that is something I am currently investigating. The standard setup is not in any way dangerous, though I admit it may not be up to numerous high-speed stops. I would imagine that better brake fluid, braided lines and different pads will make a world of difference on their own.

I drove round Donington on a trackday in a completely stock Aygo and the brakes were fine. Outbraked a CTR going into the chicane :P

I think you might use greenstuff pads and maybe some slotted rotors and braided lines, but I don't think major work is needed. The light weight of the car and relatively high cornering speed should protect the brakes.

I'm currently looking for coilovers to fit the Aygo and track rubber small enough to fit the wheels. Anybody seen either?

Paul.

[Babybadger]

Just out of interest will an MMT box handle this supercharger? Lots of people seem to be dumping them because of the jerky gearchange.....sounds ideal for a blower to be nailed on it.....

[adilmon]

Just out of interest will an MMT box handle this supercharger? Lots of people seem to be dumping them because of the jerky gearchange.....sounds ideal for a blower to be nailed on it.....

I think the software that controls the MMT will be more of a problem. It decides if you are engine braking/ over taking or on a hillstart based on the rpm, engine load etc. If you increase the power with MMT you might find out you've run out of gears. Just something to think about...

[Zaaro]

Thats the brilliant thing about an MMT though. Even though sometimes it is caught out with hills etc you can just stick it in manual mode and correct it. Simple

Dont see why the supercharger wouldnt work with an MMT

[adilmon]

Thats the brilliant thing about an MMT though. Even though sometimes it is caught out with hills etc you can just stick it in manual mode and correct it. Simple

Dont see why the supercharger wouldnt work with an MMT

Well that's ok if you can override the automatic mode. Personally, I'd only have mmt if it came with TCS. I like to have clutch control

BTW, Toyota believe that any torque over 130Nm will shorten the life of the gearbox. (it's what toyota detuned the diesel versions output to)

[zakelwe]

Are people really dumping them because they are too jerky? True, they are desperately slow in auto mode but in manual mode on downshift they are not jerky at all and faster than a manual, in up shfts they are smooth and adequately quick unless you are really gunning and it tends to play safe compared to a human. it is still smooth though.

The biggest problem when driving it hard is that the gearing is so long you lose 2500rpm by the time the next gear is in place, mind you this does put you just above the torque peak ...

The main issues are

1) It might be that the aircon unit for cars so fitted gets in the way, that is what reports say, not sure how true.

2) Clutch might have fun with the MMT and the supercharger.

I say the latter because sometimes with the MMT if you are stationary in first and give it loads of revs, for instance if you trying to nip into a side road or park and need to be hasty to avoid oncoming traffic, the car will rev up but not go anywere while it works out what is going on. I did this last week to park in my drive and when I got out burnt clutch material gently wafted up. My clutch on my old Yaris did 90 000 miles before wearing out and that never smelt at all, if this one only last 40 000 miles then I may be making a claim on warranty because it can't be me "riding" or abusing the clutch can it if it is semi auto !

Getting back to the supercharger, I still plan to do one when my warranty runs out if the financial situation has improved somewhat and I still have the car.

Regards

Andy

[Jan van de Wouw]

Even though sometimes it is caught out with hills etc you can just stick it in manual mode and correct it.

As I understand the software still monitors the engine and gears in "manual" mode.

If the software thinks you're overrevving it will still shift up to keep from damaging

something. No firsthand experience though, just what I've read and heard...

[zakelwe]

Even though sometimes it is caught out with hills etc you can just stick it in manual mode and correct it.

As I understand the software still monitors the engine and gears in "manual" mode.

If the software thinks you're overrevving it will still shift up to keep from damaging

something. No firsthand experience though, just what I've read and heard...

You can rev all the way up to the redline in manual and it will not change gear as far as I am aware, it probably will stop you changing fro 5th down to 1st at 70mph though.

I thrash my car quite mercelessly on occassion, like the other night when I was chasing an older BMW 5 series through some bends/straights and was easily hitting 65/90mph in 2nd and 3rd. with no upshifts from the MMT unless I requested it.

Note I was "in Germany" at the time, hence the BMW of course.....

Regards

Andy

[Dinky_05]

i hated the mmt when we got it....takes some getting used to as you have to remember it isn't an auto, more a manual box assist......in manual mode its pretty good....in auto its a bit thick but fine for around town. the trick is to feather the throttle - if you back off completely just as its about to change up (or back off totally when slowing down) it gets all confused and that's when the clonking starts. once you realise this the jerky changes are a thing of the past.

[Wild west Drifter]

MMT in manual mode rules- don't like it in auto mode seems very slow.

Mind you I'm not adverse to bouncing it off the limiter,

[Zaaro]

i hated the mmt when we got it....takes some getting used to as you have to remember it isn't an auto, more a manual box assist......in manual mode its pretty good....in auto its a bit thick but fine for around town. the trick is to feather the throttle - if you back off completely just as its about to change up (or back off totally when slowing down) it gets all confused and that's when the clonking starts. once you realise this the jerky changes are a thing of the past.

Nice post, this sums up the MMT gearbox, just needs getting used to