6spd Mk1 Turbo in the Toyota Sprint Series

Discussion and technical advice for 84-89 AW10 & AW11 MR2. 3A-LU, 4A-GE, 4A-GZE.

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kaiowas
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Re: 6spd Mk1 Turbo in the Toyota Sprint Series

Post by kaiowas »

I had arrived at this wheel setup some years ago before I even thought about the 6 speed option (My original intention was to use 225/45/13 R888s but these are in short supply now and the size hasn't been continued with the new R888-R). It's just taken me a while to bring it all together

My motivation was that I needed wider tyres for more grip but didn't want to increase the gearing given that at the time I was using a standard 5 speed and had significantly less power. Dropping to a 13" was the only was to achieve this as any wider 15" tyres were too tall and wide 14s aren't really available. Lowering the whole car without screwing up the geometry by virtue of the smaller overall diameter was an added bonus.

With the current setup I may find that I'm actually under geared now on some faster tracks, particularly once I turn the boost up, will have to see how it goes.

Brake wise I'm running standard mk1b up front and mk2 '22V' calipers on mk1b front discs at the rear. Carbotech pads all 'round.
kaiowas
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Re: 6spd Mk1 Turbo in the Toyota Sprint Series

Post by kaiowas »

Had the turbo setup mapped properly yesterday which means I can now run full boost.

Its now making 267hp at 1bar which is a fair step up from the 208hp at 0.6 bar I had last season and a long way from the 160 or so I had with the SC.
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Lauren
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Re: 6spd Mk1 Turbo in the Toyota Sprint Series

Post by Lauren »

That is impressive. How long do you think it will last?
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Ben
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Re: 6spd Mk1 Turbo in the Toyota Sprint Series

Post by Ben »

Lauren wrote:That is impressive. How long do you think it will last?


:lol:

Impressive numbers Phil. Am sure I'll see it at one of the Javeloyota rounds this year :)
2001 BMW M5 (Bahnstormer) | 2004 RX8 231 (the Racecat) | 2001 Volvo V70 (Swedish eBay barge)

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1989 MR2 Mk1b T-bar | 1988 MR2 SC Super Edition
kaiowas
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Re: 6spd Mk1 Turbo in the Toyota Sprint Series

Post by kaiowas »

Lauren wrote:That is impressive. How long do you think it will last?


Well there's a few non-OEM bits on it now and it has prior naval association so it'll probably fall apart after five minutes or so.

On a more serious note there's no reason to believe it will have any particular issues. It's not exactly crazy power for a boosted 1.6 and the gearbox is probably the weak point.
PW@Woodsport
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Re: 6spd Mk1 Turbo in the Toyota Sprint Series

Post by PW@Woodsport »

I personally don't think you will see a gearbox issue, I've yet to hear of anyone blowing up one of my 6 speeds, some of which are bolted to SC motors.
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kaiowas
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Re: 6spd Mk1 Turbo in the Toyota Sprint Series

Post by kaiowas »

Famous last words there Paul! First round didn't end very well - broke the gearbox after 1 run! Nothing to do with the power or anything though, I'd rebuilt one of them with the longer 6th from the Celica 140 'box and managed to neglect to install the snap ring that locates the 5th/6th gear selector hub. Once under load the hub moved down the shaft, destroyed the hub and the 6th gear and eventually left me with no neutral. Live and learn! I was off to Spa the next day as well so had to do a double-quick gearbox change.

This weekend was round 2 at Croft which went considerably better. Somehow I managed to win the whole damned thing (Adrian missed this round and the two Celicas that should have been quicker than me both had mechanical issues) making a 4A powered mk1 the first MR2 to win a round of TSS outright. It even motivated me to process some video of my best run for the first time since the turbo was fitted:

https://youtu.be/V6qQbfWxEJQ
PW@Woodsport
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Re: 6spd Mk1 Turbo in the Toyota Sprint Series

Post by PW@Woodsport »

Ah that is an easy mistake to make I guess, it just makes you build the next one better :thumleft:
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aw11rally
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Re: 6spd Mk1 Turbo in the Toyota Sprint Series

Post by aw11rally »

Correct me if I'm wrong, was that 0-60 in 4sec and 0-90 in 8sec?

What an awesome machine you've built.
kaiowas
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Re: 6spd Mk1 Turbo in the Toyota Sprint Series

Post by kaiowas »

According to the data logger, I think the best launch of the day was 4.5 to 0-60
kaiowas
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Re: 6spd Mk1 Turbo in the Toyota Sprint Series

Post by kaiowas »

The faded orange was getting a bit much so I decided to try my hand at vinyl wrapping. Bought some appropriate tools and 10m of Avery Supreme gloss orange and set to work.

First off, remove all of the stickers to show just how much it's really faded:

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Over time most of the old panels have been showered with grinder sparks leaving nice rust stains and general rougness to the panels. Rather than have to deal with this, some bolt on panels were replaced, others were rubbed down and given a quick coat of paint to cover up the massive contrast variations that would show through the very thin vinyl.

These first couple of panels were wrapped off the car to give me a chance to decide it was all too hard and give up. The louvres on the engine lid were tedious as anything!
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All went ok though, so time to start for real. No going back now...
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Biggest panel on the car done
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Working down the passenger side
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Similar story down the driver side, complicated by a fibreglass front wing where the paint reacted massively meaning I ended up prepping and using a spare one
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Overall I'm happy with how it went. It's not a perfect job but for a first attempt and for a race car it's plenty good enough. Most of the imperfections are due to the underlying panel prep not being good enough with only a couple of minor areas where the wrapping isn't up to scratch (mostly minor creases where I could quite get rid of excess material). It was all part of the learning and if I did it again I reckon it's be pretty much spot on. The hardest parts of the car which were really worrying me were the ends of the rear quarters where the panel has some pretty tight curves in 2 dimensions and in the end those bits went really well.

A couple of nice shots before the stickers went on:

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And one of the sponsor stickers:
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Next plan is to sort out the rusty header rail across the top of the windscreen. This was going to mean having the screen out. This has now become a bit more pressing as the rust has caused the screen to start to crack at the top in the last week or so. I'm sprinting at Anglesey this weekend and I expect the crack to be right down the screen by the time we're done, it's likely that the journey up on the trailer will be enough to do it! Once I've got the header rail repaired the plan is to wrap all of the black bits with a gloss metallic black.
jimi
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Re: 6spd Mk1 Turbo in the Toyota Sprint Series

Post by jimi »

Nice job, that looks great! :clap: well worth the effort.
pistol pete
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Re: 6spd Mk1 Turbo in the Toyota Sprint Series

Post by pistol pete »

Having seen it in the flesh yesterday you did a top job buddy
Tareim
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Re: 6spd Mk1 Turbo in the Toyota Sprint Series

Post by Tareim »

Looks much better now with the non faded orange, good work on wrapping it, I would've given up almost immediately as I can never get it to lay down without bubbling or it sticking to itself
Gordy
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Re: 6spd Mk1 Turbo in the Toyota Sprint Series

Post by Gordy »

It's pleasing to see C868 XVT still providing you with smiles. Keep it up!
kaiowas
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Re: 6spd Mk1 Turbo in the Toyota Sprint Series

Post by kaiowas »

Gordy wrote:It's pleasing to see C868 XVT still providing you with smiles. Keep it up!


Cheers, new season starts Saturday so nearly time to go again.

Last season ended with a 3rd place overall championship position despite some kind of mechanical issue at every round. Not done much to the car over the winter so will see how it goes.
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