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Discussion Starter · #21 ·
For reference, I was able to do a Q&A with the team that tuned the Coyote engine for Ford. WOT tuning took them a month, part throttle and transients was about 6 months, and cold start/warm up was about a year. To be fair, they had to tune it for perfect starting in all conditions.
Yeah, not surprising. Guess that's the difference between a corporate approach and a hobbyist approach. ($$$$)
 

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Discussion Starter · #22 ·
And emissions, which is a whole order of magnitude more complex.
I generally put in about 60-80 hrs of tuning on a setup until I feel it’s 95%+ good. That last 5% I sometimes chalk up to measurement uncertainty on sensors, so to iron it out can chase your tail.

The OEM guys all have lab level stuff, which makes that a non-issue.
Yeah, I'm all for minimizing emissions but fortunately live in a state that doesn't mandate testing.
 

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Discussion Starter · #23 ·
I would take professionally tuned with a grain of salt, I've seen the work of a couple and it was pretty mediocre. The problem with tuners is that the good ones cost money and no one wants to pay the money to have a map dialed properly. Unless you can drive the car and validate that it drives how you want, I would pass. I would also never buy another person's project without giving it a thorough look see.
It's getting a thorough eval. I figured if it dynos at 501 hp tune must be half-way decent. The curve looks decent, for torque also.
 

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Discussion Starter · #24 ·
+1

it’s not down to the tuner skill, it’s down to someone only paying for a quick 1 hr street tune and maybe 3-6 pulls on a dyno to do WOT.

It generally takes at least a few hours to do WOT and transients to that well, then about 20-60 hrs to really nail down transients and partial throttle everywhere.
Tune cost 1,000 bucks. Does that equate to a good, medium, or minimal tune?
 

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Probably decent/medium. Likely has a few little transient things that are a little off you’ll only see when driving it a while. Probably runs well at WOT.

I imagine they did more dyno runs than street transient tuning, which is why just driving it around you might see the odd hiccup here or there.
 

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Agree. You'll likely have some weirdness at very low throttle positions and speeds, think cruising around parking lots in 1st gear under 2000 rpm. It'll probably also have some interesting cranking and starting behavior in cold weather.
 

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Discussion Starter · #27 ·
Well, car has the Gear X gear kit, the one with Synchros, so that's good news.
The axles are from Insane Shafts, rated for 1000 HP, so that's good.
The tune was done by Kpro (cost $1000.) so that's probably at least an OK tune.
Car itself looks decent, paint is about an 8, no dings or dents, no rust, but 180k miles.

Think I'm probably gonna go for it. Seller wants 17k, I'll offer a bit less and see what happens. I'm probably gonna have to change suspension, brakes might be OK as is, will need to see if they do the job. Well, all comments and advice have been a big help. Feel free to offer any last-minute thoughts.

I'll post what happens, thanks again!
 

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Moroccan Gold Imports
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Seriously 500whp in this chassis is just nuts. Put up some vids!
 

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Discussion Starter · #32 ·
Other than some auto-crossing I won't be racing. Given that, and looking at the dyno sheet, can I get more low-end power, at lower RPMs, by going to a smaller turbo?
(the turbo on it is a Garrett gt3076)
 

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Moroccan Gold Imports
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You could go to the GTX3071 and go with the smaller housing to shift the power band leftward. I wouldn't want this car for autocross. Never mind the spool, the response will be too slow for parking lot racing. 28 series garret would probably be best for an autocross sized turbo. You would give up a lot of top end power compared to this monster setup! Leave it as it is and do track days instead of autocross.
 

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Discussion Starter · #34 ·
Can't say I disagree with your logic.
Current turbo starts making boost around 3,300 rpm. At what rpm will a small turbo (e.g., garret 28 series) start making boost?
 

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Moroccan Gold Imports
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I would look at some dyno plots of each turbo on a K20. The question in my mind isn't so much when does it start making boost, but at what RPM will it be (mostly) spooled up. Nearly half your power band is lag city. Then again, you still have ~4000 rpm power band after that the way the k20 winds out. I would love to drive this car.
 

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Discussion Starter · #36 ·
Yeah you make a good point. And sometimes you have to give a little to get a little. Torque at 4000rpm looks pretty good. After that everything looks good. I should probably not change things much. But could the curve be moved left by a change to the wastegate?
 

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Discussion Starter · #37 ·
Thinking about it, messing with the wastegate is probably not gonna help with moving the power band. Maybe 'grudge night' at the drag strip makes more sense than autocrossing but now I'll have to worry about traction control, lol.
 

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No that won't do it, you could change the exhaust housing on the turbo to a smaller size and shift it leftward slightly. What size housing on there now?
 

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Discussion Starter · #39 ·
Not sure, the exhaust housing is whatever came standard with the Garrett gt3076. I guess changing to a smaller size would lower the A/R ratio. Yeah, that might move the curve to the left. It would lower peak hp, but at 500 hp, there will be plenty left. I don't think changing the exhaust housing would be a big deal. I'll have to look into it more. Thanks
 
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