Jamesc
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| posted on 5/10/16 at 12:42 PM |
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ZX12R Turbocharging
I'm not currently looking to turbocharge my ZX12R, but it is something I have considered for the near future as a project. It's not
because I feel I need more power or feel the need chase numbers by the way! Hopefully this thread can be a discussion about what is required and
people can share their knowledge and experience of turbocharging.
What I am mainly researching is a low boost application (~4psi?) where the engine is not modified, just the ECU map. A few questions to get
started:
- What engine modifications, if any, would be required at low boost levels? (clutch?)
- Would an intercooler be required?
- Can the turbo be plumbed in to the existing oil system or will it require a separate pump?
- What size of turbo? Does the large rev range influence turbo choice? Any idea on ideal A/R?
- Does increasing fuel rail pressure negate the need for higher flow rate injectors? - Not sure how much extra will be required, but most people below
6/7psi are able to tune it within the Power Commander range.
I have read a fair few budget build blogs, but it would be interesting to hear first hand from people who have experience in turbo motorcycle engines.
Most of the people who have done similar things have not modified as much of the engine as I thought would have been required. I'm sure there
are loads of questions to be asked, but this is off the top of my head so far!
Thanks
James
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dave_424
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| posted on 5/10/16 at 02:45 PM |
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Have a read of my threads here if you haven't already.
http://www.locostbuilders.co.uk/viewthread.php?tid=193224
http://www.locostbuilders.co.uk/viewthread.php?tid=184992
http://www.locostbuilders.co.uk/viewthread.php?tid=191476
Heavy duty clutch springs for low boost 7psi, that's about it
Intercooler helps, unless you have absolutely zero space, do it.
Turbo oil feed can run from the existing oiling system
Something like a TD04-16T would be reasonably sized or T25 or T28
[Edited on 5/10/16 by dave_424]
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Jamesc
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| posted on 5/10/16 at 08:30 PM |
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Thank you for the links, I have read them all and found them really helpful.
So you don't have any problems with the clutch on low boost? I'm planning on changing the clutch over winter and wonder whether a heavy
duty one would be worthwhile for future proofing, but cannot find any information on line about them. I already have the HD springs.
I have noticed that most turbo builds use large-ish turbos!
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dave_424
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| posted on 5/10/16 at 09:55 PM |
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HD springs should be fine, I originally used EBC HD springs, but when I went for more power I used the strongest springs I could find which were some
super heavy duty R1 ones from America, I forgot which website.
Don't bother changing the frictions and steels to anything other than OEM Kawasaki
The rule of thumb would be to use a turbo from a 2L engine and that it can produce the amount of power that you want.
EDIT: just remembered they were from Brocks Performance
[Edited on 5/10/16 by dave_424]
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Ugg10
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| posted on 6/10/16 at 07:18 AM |
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http://www.holeshot-racing.co.uk/images/pdfs/turbo-charging/tbikekawzx12_120831.pdf
The hole shot racing kit will give you some clues as to what is needed. Iirc they use Mitsubishi evo turbos, the galant vr4 may provide cheaper
ones.
[Edited on 6/10/16 by Ugg10]
---------------------------------------------------------------
1968 Ford Anglia 105e, 1.7 Zetec SE, Mk2 Escort Workd Cup front end, 5 link rear
Build Blog - http://Anglia1968.weebly.com
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Jamesc
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| posted on 6/10/16 at 08:08 AM |
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OK great, I already have Barnett springs fitted. I'm not sure if the clutch has ever been changed as the engine has done around 9500 miles, so
was planning on changing it as a fail safe for next summer.
I had a look at the Holeshot Racing list, thanks for the info regarding the turbo - 'Modified turbo to suit bike application' is nice and
cryptic. I assume that's probably clocking the turbo housing and fitting oil feeds or something?
Interesting that they change the injectors and tune with the power commander. I think I need to do some more reading on injectors!
I hadn't noticed before that they claim 8psi = ~260RWHP either.
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Ugg10
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| posted on 6/10/16 at 09:35 AM |
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You will need some way of changing the fueling, power commander seems to be adequate for low boost. You don't get something for nothing, more
power equals more air and more fuel, the more air is provided by the turbo, you need to find a way of getting more fuel into it, that's what the
power commander does - changes the signal to the injectors and tells them to stay open a bit longer (simplistic but that is my understanding of how it
works).
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1968 Ford Anglia 105e, 1.7 Zetec SE, Mk2 Escort Workd Cup front end, 5 link rear
Build Blog - http://Anglia1968.weebly.com
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Jamesc
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| posted on 6/10/16 at 09:45 AM |
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I understand that the fueling will need to increase to match the increase in volumetric efficiency. I have a power commander fitted, so understand how
that works.
What I meant is, I was surprised that they have changed the injectors and tune with the power commander as you can't tell the PC or the ecu what
flow rate the new injectors are... Does that mean that the flow rate doesn't matter and you alter the duty cycle to achieve fueling? Assuming
the impedance of the injectors matches the original ones?
I'm sure I have read that the stock injectors are around 330cc and are worked quite hard as standard. I also think I have read that you can
increase the flow rate by increasing fuel pressure? I need to find some good reading on this!
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Ugg10
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| posted on 6/10/16 at 10:27 AM |
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From what I can tell, the power commander intercepts the injector signal from the OEM ECU so knows when to open them (that is fixed and linked to the
crank position/valve opening), it then keeps them open based on the power commander map and then closes them until the next open pulse is seen from
the Oem ECU. Therefore, if you change the injectors or the fuel pressure to get higher flow rate you will need to rolling road the engine/car/bike
after to set the power commander injector duration map to get the fuel/air ratio correct.
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1968 Ford Anglia 105e, 1.7 Zetec SE, Mk2 Escort Workd Cup front end, 5 link rear
Build Blog - http://Anglia1968.weebly.com
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