Toyota A6 Blacktop
#1
Hi All

I have just been told of this forum and I must say, what a welcome relief to have a forum dedicated to what we are passionate about with no hidden agendas.

I have been building my Locost for what will be two years in July. I won't bore you with all the details of the build, I have created a blog for that.

What I would like to know is what exactly went into the Toyota 20v Blacktop A6 spec motors that you guys in the B class used to run in 2005/6? I bought my motor from AJ on the premise that it has approximately 10 - 15% more umph than the stock motor. Is this correct?

If you get a gap, have a look at my build at: http://philsvelocity.wordpress.com

Cheers,
Phil
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#2
A6 mods are all done on the cylinder head and cams. The only mod to the bottom end was the pocketing of piston crowns to clear the valves due to the increased valve lift. Cam specs 305 deg duration and increase in lift on both cams ( Can't remember the actual numbers ) Cylinder skimmed and compression raised. Head was flowed. Exhaust pulley was changed to a vernier pulley to be able to set cam timing. Intake pulley was also modified to restrict the VVT movement. VVT was disconnected. That's about it.
Power increase of +- 15% sound about right. Max power and torque much higher in the rev range and narrow power band compared to stock motor. Due to this gear ratio's becomes an issue. We also raced on race fuel only due to the high compression, although I'm told you can use pump fuel but will have to alter the ignition timing.
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#3
Thank you Derek for a very comprehensive answer.

As far as the power goes, AJ said he was getting around 99kw with his GoTech (I think), I have a MicroTech which I imagine/hope will squeeze a bit more out. The more horses the merrier I say, especially because the poor car has to lug my frame around.

As a matter of interest, if I were to sell the motor (excl. GB), what do you reckon I could get for it?

Cheers and thanks again,
Phil
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#4
My A6 is standing in my garage gathering dust. We changed to standard motors. I advertised it once but got silly offers around R6000. If you consider a standard motor from a scrap yard goes for R4900 now and the cylinder head work and billet cams ( which is what I used) is around R7000 then +- R10,000 is the minimum I would consider ( I included the Gotech, wiring harness, coil igniter and Hall effect dizzy). I would rather put it in my lawn mower than give it away for a ridiculous price.
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#5
Hmmm, OK I was ripped.
Another lesson learnt.

Cheers,
Phil
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#6
I did a motor swap on my birkin to a silver top import motor.
When it was setup by gotech it made 86Kw on the wheels. This was when the motor had pretty much not been started since leaving the corrolla body it was made for in japan.
Since then it has loosend up a bit and about a month ago I stuck it on KAR's dyno appart from them telling me I should get the VVT to kick in at about 3000rpm It was making 125Hp on the wheels.
converters here
The moral of my story Jap import motors make enough power for what they cost. The R3500 I spent on it wont cover even some basic repairs top the motor so it is disposable. So, I rev the guts out of it and dont go around worrying about a R10K rebuild and what would it cost if I broke something.

Unless you want Caterham R500 type of performance and who won't. 100Kw and 600Kg is plenty for most cars. Infact until you are very famiriar with your car and what happens when you push it a little to hard more is probably too much.

Oh BTW I have posted my entire rebuild process on another forum. I will repost it here sometime Birkin Forum
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#7
Very true. This is exactly the reason why we decided to restrict Lotus Challenge Class B to standard motors (Toyota 20V) only.
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#8
Hi
Believe it or not I have not driven one of these cars yet, despite the massive costs I have incured to date. I have been taken around Zwartkops in a Rocam powered Westfield and I was very impressed with the performance. I have seen and heard Anton's 20-v a few times on the track and his car mooooves.
I have had a few mates trying to convince me to turbo/supercharge the motor but I have said that I first want to get to grips with what I have. It's all about power to weight I keep telling them.
I can't wait to get her on the road now.

Derek, a question for you; You mentioned that the A6 has VVT removed/disabled, will that pose an issue with the Microtech ECU that is pre-set for the standard 20-v Blacktop?

Cheers,

Phil
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#9
Bang for buck you cannot beat a 20v! For a road/track car I'd pick the cheaper silvertop over a blacktop.

Michael: 86kw is very optimistic - I had a good silvertop (also on gotech) and that only managed 76kw on Braam's dyno


Phil: VVT is there to increase midrange torque (mine is activated from around 3000 to 6500 rpm - can't remember the exact points). On the A6 it was deactivated because they ran a high performance cam. I agree with your philosophy - before you search for more power, first learn to use what you have. Over the years class B has often proven that power isn't every thing
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#10
Morning Guys

One must not loose sight of how we are comparing standard motors to the A6 spec motor. Most people compare their motors at Zwartkops because that is where we get to spend the most time.

On the A6 motor the cam timing, higher fuel pressure, higher compression, no VVT, .9 TRD Head gaskets, adjustable fuel regulators, 8.5 mm lift swirl cut valves etc. This was an awesome motor capable of revs in the mid 9s. What I have found is only a 0.5 sec difference at Zwartkops but at Kyalami there is a 2 second difference and the same at Phakisa.

There is nothing better than the sound of a well modified Blacktop in fullcry. Due to the cost exercise of creating cost effective Class B racing we have done the right thing by returning to standard motors. I personally have spent money in a few different areas to achieve better handling but it will be a while before I will see a sub 2 minute at kyalami again.
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