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Really looking forward to seeing what you manage to get from all this. Just out of interest do you have an idea of what it weighs?
 

It weighs next to nothing, a few kg, thin wall all alloy construction and even the TB is all alloy. It should be a fair bit lighter than the standard 1300 set up that's currently on it. 

sniper

Last weighed in at 1120kg fully fuelled but she's lost a few bits since then....

100 bhp per ton was a goal I chased as a young man, back in the Escort/Sunbeam days. The car feels close to that goal now but we'll find out next week.

Just had a blast to the butchers and it feels pretty quick at certain loads, the current "tune" will run it ok but the fact it has sweet spots means that there is a lot to do and more to get from it.

sniper

 

The car has been at the dyno for a couple of weeks, the first install attempt failed as the crank sensor signal was getting lost just above idle rpm. 

I spoke to Riccy who had some problems during the install of his DTA S80 ecu, he had similar issues with the crank sensor which he cured with shielded cables that are grounded to the engine. 

I passed that on to the tuner and I'm assuming that no news is good news.... I haven't been told to collect the car lol....

This is the inspiration for the way I have tuned the car... S1600 rally cross engine 218bhp/185nm @8500rpm.

 

I'm not rich enough to go all steel and forged, so my rev limit is a meagre 6500rpm. I'm also lacking a modified cylinder head and high lift cams so my power expectations are much lower at around 130bhp...

I'm like a kid waiting for Christmas....

sniper

The last few month's were sent to me as a trial....

Car goes to the tuner for the standalone ecu install, new induction system and a full map.

Catch covid (all jabbed so just normal flu)

Sensors not available so the new inlet plenum can't be fitted. Decided to tune with std induction.

Car comes back from the rolling road and the gearbox dies on the way home.... New box 2.5hrs away

Gearbox done and not happy with the drive, it's faster by a mile in the mid and upper ranges but part throttle is twitchy and brutal. VVT was not there...

My dicky ticker caused me to pass out during a coughing fit, on the way to a hard landing on my tiled floor, my fleece top catches in the base unit door handle.... I wake up suspended by my waist above twisted legs, my knee was twisted and I was in agony, 12 weeks later I'm still limping...

New granddaughter, "Kiara" born at 8lb6oz.

It's been quite a few months.....

So with gearbox swapped, a slot sorted to go back to the tuners now that I can drive (Left knee so the clutch was impossible)..

1600 VVT with 1300 induction using 1600 injectors, K&N Panel filter, 4-2-1 exhaust manifold, 2" sports cat exhaust...... 98.3 FW BHP / 117ftlb Torque

 

Kevin at Dynotech plugged the laptop in and we went for a drive and cured all the part throttle problems.... He reduced part throttle fuelling by 30% which as well as curing the brutish behaviour, should save a few pounds in fuel costs.

Kevin also explained a little about the VVT, some I knew but much I didn't, I found it quite informative.

VVT advances the exhaust cam timing, this isn't so much a performance modification as an economy/emissions system for low rev driving. The emissions are lower with reduced exhaust cam timing (valve stays closed longer, more fuel burnt) but as the revs rise, there is a point where the retarded exhaust timing, negatively affects power output (4000rpm on the Jimny). VVT then advances the timing and a modest surge in performance is felt.

The full advance that VVT provides, comes in unnoticeably at 1500 rpm in this tune, nothing additional happens. The benefits (more torque) are there from part throttle to the 6500rpm red line.

The race inlet is being fitted up with sensors and will be fitted in the next month or two...

A little disappointed that it didn't break 100bhp but that's all in my mind.... The important figure is the 117ftlb of torque which makes the car nippy and capable... 5th gear at 25mph and pulls cleanly from 1800rpm.

For what it is, the Jimny is now a pretty quick car and even more fun..... Harassing big 4x4's is not a new pleasure but I can out accelerate the V8's now. 

Now to do a few numbers and see if I can afford the Big Jimny meet...

sniper

Sounds like a mad few months, hopefully it's all plain sailing from here.

Sounds pretty good and gets the power down well...

sniper
(hope the link works..)

Sounds nice that, just right without being too OTT. Looked good off the line as well.

Not had much occasion to use the car off road but the little I have done has shown the engine tune to be pretty good on rough ground. The torque is such a big improvement, far fewer gear changes and no hint of pinking when loaded at low rpm. Pulling cleanly from 1800rpm in any gear.

On tarmac it's an absolute ball.... 90 bends at 20mph in 4th. I'm surrounded by long slow (30-50 restricted) climbs and the car hated them when cold, no problem at all now. Straight in to 4th in the 30's and 5th in the 40's.

The recent hot weather has been lots of fun as far as grip is concerned, tight and twisty B roads are great fun.

The rain came for the first time in a few weeks yesterday and the roads were a bit greasy. The car can now break traction in a straight line in any gear when given a boot full..... Not a positive really but I'm the only driver and should be able to keep myself under manners.

It still needs further tuning, part throttle manners are much better but still a bit too reactive, making low speed driving just a little jerky.

The SS1600 engine I based my tuning thoughts on has been an interesting thing to investigate. Well over 200bhp and naturally aspirated... I have found an engine for sale and some first hand knowledge from the seller. 10K for a secondhand engine, I might not be fitting it in my car lol. Special blocks, modified Hyabusa crank, forged, billet rods, custom cams. A full race build rather than a production engine uprated.

I still have the induction set up to install but find myself quite happy with the power for now. I am going to get a head ported and flowed, possibly some bigger exhaust valves to try and push the torque figures further. 

For now, I think it will go to AP Racing in the near future for a further tune on their rollers. He's a guru in the grass track and rally world, luckily he's local. That should sort some of the finer part throttle issues and he has a reputation for finding power from nowhere.... Got to find £300 for a session so it might take a few weeks.

The engine has shown the gearbox wanting again, no problems, just a slow shift and a short first gear. So I'm going to look in to the MX5 box again, although Keithy has made progress with his Lexus 6 speed conversion. There is also a Ford type 9 with clubman SC/CR Quaife gears in a mates shed, now that would be a thing... Whichever way, the gearbox has to go.

So that's another two years of pocket money...

sniper