Stock ECU - Dyno results - questions

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tommy10101
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Stock ECU - Dyno results - questions

Post by tommy10101 »

Hi all,

Had my rev3 turbo on the dyno today.
Mods: st205 charge cooler, decat downpipe and exhaust, mbc at 16psi. Stock ecu.

Happy with the 280bhp but 245 lbs of torque seems a bit low compared to other graphs I’ve seen. The shape of the power curve is very nice though.
1D706F48-CBB7-427C-BEB9-2286664E3414.jpeg
Questions:

Could the low torque maybe be down to the lean spot in the AFR as the boost comes on as seen below?

Ive been told this lean spot happens with all stock ECUs?

Should I be concerned with this AFR curve? The car is used mainly as a track car so I want to make sure it doesn’t go bang and the AFR is all correct. The chap at the dyno said it is not ideal, but there was no knocking. What do you guys think?
9B1F9A6F-FF51-4D0C-9684-E8807355B4D8.jpeg
Looks like I would really benefit from an after market ECU to map out the Lean spot.
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tommy10101
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Re: Stock ECU - Dyno results - questions

Post by tommy10101 »

Also I should add, I have already done 1 track day with the car and the engine was faultless. Intake temps were kept low and it felt and sounded like it was running perfectly.

Just want to know if that lean spot is dangerous and needs to be corrected before I track the car again
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Re: Stock ECU - Dyno results - questions

Post by MR2DI4 »

where is the boost pressure vs AFR graph ?

I presume the test is a third gear run and that's power at the engine ?

Yes it's down on torque compared to my Rev 1 mine is 270 from memory.

Graph looks pretty normal to me that's just a blip before it turn very rich at higher rpms. More power would come from more boost and watch that curve flatten out from 4500rpm on a stock ECU.

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Re: Stock ECU - Dyno results - questions

Post by tommy10101 »

I didn’t get a boost pressure graph for some reason but from my gauge, it is peaking at 16psi and want to leave some room for colder weather so it doesn’t hit fuel cut. I’m pretty happy with the power, and as its a track car the lower torque doesn’t matter as much.

Just wanted to see people’s opinions on if that AFR curve would be dangerous. And sounds like you don’t think there’s much cause for concern.

Car ran perfectly on track so think I will just leave as is.

Thanks
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Re: Stock ECU - Dyno results - questions

Post by SonicSW20 »

The boost pressure/AFR graph is really needed to ascertain if its a potential problem or not. If you're piling in 16psi at that point then thats a bit of a concern. If its only getting to 16psi at 4500RPM+ where the AFR's are much safer, you're fine.
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Re: Stock ECU - Dyno results - questions

Post by MR2T_Jake »

Your ECU seems to move from Closed to Open loop really late.

3800rpm and a certain amount of boost detected should force the ECU to take over from the O2 sensor for your AFR... The fact its not dropping until just after 4000rpm is concerning if you ask me...

Along with that Lean spike! I would personally check 2 things...

If your injectors are Lazy / need replacing or your alternator slipped at that point and dropped voltage which can in some cases cause fuel issues for that small amount of time.

Hope you get to the bottom of this however!
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Re: Stock ECU - Dyno results - questions

Post by jimi »

MR2T_Jake wrote: 24/05/21 11:48 or your alternator slipped at that point and dropped voltage which can in some cases cause fuel issues for that small amount of time.
IMO
The chances of that happening are extremely unlikely, the alternator would have to virtually stop and the battery be extremely poor for the system voltage to drop low enough in that very short time to have any effect on the fueling ;)
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Re: Stock ECU - Dyno results - questions

Post by MR2T_Jake »

You are correct, i have read on other forums that fuel can be effected by a sudden change in voltage.

Unlikely i agree but not entirely unheard of.

Lazy injectors or something up with the ECU switching to Open loop would be my guess?
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Re: Stock ECU - Dyno results - questions

Post by tommy10101 »

That’s very interesting, thanks

I think I am going to take the plunge and go for a stand-alone ECU.

I assume this lean spot could be mapped out? Assuming I get the injectors checked and are ok.

What other benefits of a new ecu are there? Could I get rid of my manual boost controller if I get an ecu with built in boost control? Not sure how that works.

And do you think I would see power and more importantly torque gains?

I would like to increase the torque more than anything. 245 seems low:(

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Re: Stock ECU - Dyno results - questions

Post by tommy10101 »

Seem strange the ecu would be going into open loop later than usual though.

Maybe it does point to lazy injectors instead.

Do you think an aftermarket ecu would be a good move for me given the issues shown?
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Re: Stock ECU - Dyno results - questions

Post by MR2T_Jake »

The only bad thing i see in there is that lean spike at 3800-3900rpm that then drops down.

It's like your open loop spikes lean then goes "oh "censored"" and then drops drastically. Maybe pulling the EFI Fuse for 10 min and let the fuel maps stored in the ecu have a "relearn"?

Standalone should sort it out, so long as no physical problem is there such as injectors, o2 sensors.

Hope you manage to sort it out, Mine is up for a dyno run tomorrow, so hoping mine is all good :D
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