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Old 04-11-2017, 02:11 AM   #1
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Default NZ Superlap - Class Win 1600 Turbo.

May be of interest to some.

We have 3 outright classes,

- Open
- Open tyres, open aero, open engine etc.

- Street Pro
- Road Legal, Certified Race car with cage. Treaded tyre (NTo1, 03g, R888 etc - Hankook and other 2 groove illegal)

Street
- Road legal, no full cage, 180 TW tyre and above.

We are in the Street Pro class. So far we have taken 3 wins and 1 second in the Street Pro 2WD class with 1 round to go.

Overall "I think" we are running 3rd outright in the Street Pro class behind a 1200+ HP R35 and a 800 HP R32, both 4wd.

Video below is the first session at the A1GP Taupo track on the weekend. Only had 2 sessions on the saturday as we had the Classic Japanese Series 3 hours up the road on the Sunday, which we also lead class and series outright (was a big weekend).

Was stunned to drop 3.6 seconds off our previous best time to a 1.41.2 (now with aero and Xidas EDIT: and built motor). For interest sake, the r35 with aero did a 1.34 and the r32 (no aero) did a 138.8 (or thereabouts).

I LOVE my little car!

Picture for external reference and video below

.

fast laps start at 6.25 for those of you with short attention spans


Last edited by mx5-kiwi; 04-11-2017 at 07:22 AM.
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Old 04-11-2017, 05:43 AM   #2
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Nice work!
Any plans to take on the leaders?
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Old 04-11-2017, 06:10 AM   #3
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Noooooo,that is well out of my budget i'm afraid.

We are having fun as is though.

We here all know they punch well above their weight, but very few others expect a little mx5 to do any good, so its fun opening few eyes

Its not all good news though, the next day was a disaster when a primary power plug to coil broke a clip and came loose leading to severe misfire in race 1, low brakes pads lead to brake fluid boiling and pedal to the floor from 200km/h in to a 4th gear corner in race 2 and i suspect too high water temp lead to possible piston and/or ring failure on #2 (belched oil EVERYWHERE) in race 3.

Giving us a must complete - 2.5 weeks to tear down, fault find and source new parts, engine rebuild (usually involving international freight from 949) as i've now lost my "drop a round" for total points in the championship fight for 1st.

However we did set PB at that track dropping down 2.5 seconds in the process....the good and the bad. Sigh.
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Old 04-11-2017, 10:59 AM   #4
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What! Just work more hours, eat ramen noodles for the next few years, and whip out the checkbook. You will be fine.

Seriously though. It's amazing how fast you are compared to the big boys. Looks like fun.
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Old 04-11-2017, 07:11 PM   #5
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Thanks.

Very much a testament to the knowledge shared and products developed and made available here at MT.net.
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Old 04-11-2017, 08:45 PM   #6
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What did water temp. Reach? Straight water?
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Old 04-11-2017, 08:51 PM   #7
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I need to check the log but around 112 - 115 (edit: deg Celsius) was what I saw. Was a bit busy at the time so might have gone higher. Though I did drop revs down to 6800 - 7000 (from 7500) which usually reduces water temp pretty quickly.

Perhaps other racers can input on the likelihood of those temps being an issue or not?

Hoping it wasn't detonation.....will find out tomorrow when mechanic pulls head etc. Fingers are crossed it is nothing major though that seems unlikely.

Im teetering on the verge of clicking buy now on a crossflow rad the past two days but am forcing myself to wait till we see if i need any thing else, pistons, rings etc....from 949 at the same time.
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Old 04-11-2017, 11:29 PM   #8
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BP head gaskets usually let go around 255f / 123c in our experience. If you had good system pressure, 1.3bar cap, mostly distilled water, you are probably OK. Those temps lose a bit of power and hurt engine life but typically aren't catastrophic. Depending on fuel, altitude and a few other things, the BP's usually make best N/A power between 180~200f clt
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Old 04-11-2017, 11:31 PM   #9
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230-240F, yikes.
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Old 04-11-2017, 11:41 PM   #10
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I bit the bullet and ordered the radiator anyway. Thanks Emilio.
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Old 04-11-2017, 11:52 PM   #11
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FYI - motor has cometic gasket.

Overheating coincides with new airdam, new built forged motor, new larger intercooler AND raised rev limit to 7500, from 6900.

Hard to figure out what might be the cause as it only slowly happens at race pace about 4-5 laps in. Time attack and road use, no issue.

Hopefully the final 10% of ducting and the crossflow will resolve.
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Old 04-12-2017, 02:12 AM   #12
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a friend had overheating with ""new larger intercooler"". (think airflow to rad). changed back to smaller one and overheating magically went away, with no performance effect. also, I know it's tempting because it keeps making power but reconsider your 7500rpm redline. we don't have an aftermarket throttle body like the 1.8s and I broke mine very soon after raising rev limit from 7 to 7.5K. These engines have some weird harmonics happening after 7K. I swear I could see all kind of stuff in the interior vibrating and could feel it through the pedals in the higher gears between 7-7.5K
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Old 04-12-2017, 02:19 AM   #13
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Thank you.

All stuff you read about randomly here but great to be reminded and to re factor in.

You are very right in that it IS tempting to run to 7500, not so much the power as that does start trailing off but it is a big contributor to lap time in between a lot of the corners we run, passing people, holding people off etc....but at the cost of the motor, temps, swallowing the grub screw etc....probably right!

Also handy to hear of the intercooler issue, it was in my mind, so might swap back to the smaller one if the crossflow rad doesn't help.

Something else we just thought of today was perhaps we glazed the bore with aero and high g loading, pretty sure it was 1.6 +....we do run a 949 style baffle, anyone else have any issues in that area?
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Old 04-12-2017, 02:18 PM   #14
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Quote:
Originally Posted by mx5-kiwi View Post
Noooooo,that is well out of my budget i'm afraid.
i suspect too high water temp lead to possible piston and/or ring failure on #2 (belched oil EVERYWHERE) in race 3.
I find the ms3 coolant temp based rev limiter to be good for this. In case of too high water temps, I get a 5500 (or 6000rpm) rev limit, or at least I used to before ducting and new rad. For those moments where the red mist makes decisions a bit sketchy

And great work in the races!
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Old 04-14-2017, 05:15 PM   #15
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Head off, lost piston 2. Looks like a bad or failed injector, no 4 looks like it may not be the best either, weird pattern on piston.

Damn. Motor was running so well.

Least the tune was okay.

Head escaped but block may have a pitt.....have 1.5 weeks to pull down, rebore this or another block, rebuild, run in and drive then 3 hours each way for a tune before the weekend after next to try and retain the lead to win class and series.

Yikes.

Our race mechanic (legend) is giving it a go.

No pressure or stress
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Old 04-14-2017, 05:39 PM   #16
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Just saw this thread.
Wow, very cool, congrats sir.

Bummer on the failed engine, but I'm sure you'll rebuild in time, this isn't your 1st rodeo

which injectors are you running?
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Old 04-14-2017, 09:35 PM   #17
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Thanks.

Sadly it is not our first rodeo ....character building (maybe).

Injectors are a set of 550cc my engine builder/ race mechanic loaned me and started using about 2 years ago.

Have a near new set of RC 660 (?) to fit but sending all 3 sets we have away for urgent testing etc.
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Old 02-13-2018, 07:17 PM   #18
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Just a sum up of this for any ones future reference.

Injectors tested fine, problem was a cracked injector plug causing either a temporary or permanent failure. .

Replaced injector loom with one the mechanic supplied that has more robust connectors. He wasn't so keen on the OEM 1600 ones on further inspection.
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Old 02-17-2018, 12:01 AM   #19
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The discussion is academic now, but a faulty connector won't cause a lean condition. If you had an intermittent injector plug which prevented the injector from firing occasionally, it would cause the cylinder to completely mis-fire from a lack of fuel. I have a system on my car (Racelogic) which does exactly this as a form of traction control strategy. I could see it causing an issue if it were to happen for so long that it caused a brief lean condition on re-start (the RL TCS uses a skip-fire strategy to deal with this), but if it were happening that often, you would absolutely be able to feel it.

Just a thought. I would look elsewhere for a culprit if it were my own car.
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