DBrown67
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| posted on 12/4/14 at 08:37 PM |
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Zetec rolling road query
Hi guys 
I have a 2.0L blacktop which I want to run with ZX6R carbs. Done a lot of reading and I'm OK with what I need to get them running. But I have
some questions regarding getting them fine tuned on a rolling road.
Car is already running a twin choke Weber with Omex 200 ECU. It runs OK at the moment and I did have it rolling roaded and jetted etc. a while back.
If I go with bike carbs will the Omex map need scrapping and start from scratch? What about the TPS settings? Will they need tweaking if I use the
ZX6R TPS?
I ask because I phoned Bogg Bros. and while they have an excellent reputation for bike carbs they didn't fill me with confidence regarding my
ECU. They basically said bring a laptop with me with the software installed.
I could go to the original rolling road place which is a Weber and Omex dealer. I've heard that Weber DGV/DGAS main jets fit ZX6R carbs so they
would be OK on that score. But dunno if bike carbs is their thing.
Any advice/info is much appreciated. I have a basic grasp of what they do at a rolling road sesh... but it is basic!
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Ugg10
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| posted on 12/4/14 at 09:47 PM |
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Tps will need re calibrating, usually it is very simple, click at fully close, put foot to the floor on the accelerator, click again, done - basically
sets the end stops and voltage between them sio it can divide that by the number of load sites to know where it is in the map. I would have thought
the ignition map should be Ok to start with. As for jetting, have a chat to Chester sportscars as they do a lot of kits with the zx6 carbs.
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DBrown67
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| posted on 13/4/14 at 05:25 AM |
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I got the carbs from Chester sports cars. They told me they were already rejetted with 1.6mm jets but they did advises a roilling road session which I
will definitely do. I'm not fussed about peak power, I just want a nice smooth torquey drive up to around 4K rpm. If top power is compromised a
little I'm not bothered as it's a road car and I rarely go above 5K anyway.
Most people seem to use megajolt but I got this Omex 200 cheap off Ebay for £200 so it was a no-brainer. It's been perfectly fine but of course
I need to go somewhere that understands it to get the best from it.
By the way... can the needles be adjusted with the carbs on the car? Just want to be sure in case the rolling road wanted to do this.
Reason I'm swapping is because I'm sick of not being able to get to my master cylinders plus the fact my home made carb linkage on an
aluminium plate looks naff. I need to fit remote reservoirs and to do that all the carb and manifold needs to come out, so I may as well give bike
carbs a try. This isn't actually on a kit car but the info on this board is still very relevant to me needs. Thank you!
[Edited on 13/4/14 by DBrown67]
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redturner
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| posted on 13/4/14 at 07:42 AM |
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My limited knowledge of electronics is overcome by the fact that my mate sorts mine but I do know that you are probably way under jetted with the 1.6
jets, I run a 2 litr Black Top and I have 180 jets fitted to the R1 carbs, they are lovely and smooth.
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Scuzzle
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| posted on 13/4/14 at 11:45 AM |
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Bike carbs are strange things, you can have the same carbs on the same engine and 1.6mm jets might run one fine where the other needs 1.7 or 1.8. One
might need the air correction holes blocked off as it's leaning out at the top end where the other does not. One might need 2 turns of the
mixture screw where the other needs 3 or 4., dunno why but it's just the way they are.
You usually start with your jets on the small side as your starting point because it's easier to make them larger than it is is to make an
oversize jet smaller. You probably will need larger than the 1.6mm though.
You are best just to get it up and running and let the rolling road place do the rest, they will put a gas analyser in the exhaust and make sure you
are getting correct fuelling under all load conditions. The needles can be adjusted for crisp midrange as well, the carbs can be left on the car but
they will need opened up go get to the internals.
You do need a RR that is familiar with bike carbs though.
[Edited on 13/4/14 by Scuzzle]
[Edited on 13/4/14 by Scuzzle]
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redturner
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| posted on 13/4/14 at 01:13 PM |
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I fully agree that you will never find two engines that require the same set up. I used Torque Tune near Newark. He does lots of bikes and certainly
knows what he is doing. He did 2 or 3 runs with my engine then blocked the air correction jets and kept drilling upwards until he was happy with the
a/f/r across the whole range. we finished up with '075mm on the airs and 180mains with the needles lifted 1 notch.
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snakebelly
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| posted on 13/4/14 at 03:42 PM |
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Wouldn't worry about it myself, most tuning software is pretty similar, a grid of timing cells with rpm up one side and the tps values on the
other.
Were not speaking injection or anything fancy here so the only calibration that should be needed will be the TPS and the rest is timing sites which
Bogg Bros are more than capable of setting up.
They cant have the tuning software installed for every ECU out there. I have been asked to supply a laptop with software before now and it really
wasn't a problem.
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