Anyone did the mt convention before? I got several questions about it🙏🏼

[stevecct]

Question one. Can I use the AT ecu plus a E-manage ultimate for the mt gearbox?

Question two. Is it necessary to change the AT engine harness to MT engine harness if im going to use the MT ECU?

 

[Honcho]

Question one. Can I use the AT ecu plus a E-manage ultimate for the mt gearbox?

Question two. Is it necessary to change the AT engine harness to MT engine harness if im going to use the MT ECU?

I have a bit of experience on this. As to number one, I don't know what the E-manage ultimate is. However, you can use the AT ecu with the MT. You will be rev limited to 7,500 rpm though.

As for number two, you can use your AT engine harness no problem.

@Big McLargeHuge

 

[stevecct]

I have a bit of experience on this. As to number one, I don't know what the E-manage ultimate is. However, you can use the AT ecu with the MT. You will be rev limited to 7,500 rpm though.

As for number two, you can use your AT engine harness no problem.

@Big McLargeHuge

its an aftermarket piggyback unit, to adjust the data of ecu

https://en.trust-power.com/products/electronics/greddy-e-manage-ultimate

That would be a problem if limited the rev to 7K5.....

so MT ecu is the only way out?

 

[stevecct]

or i just simply swap the ecu mode to manual by removing the R4 resistor?

 

[drew]

Unless you have changed out the AT camshafts to the MT version, you should leave the AT ECU alone.

You can modify the RPM limit with a PROM burner using the AT fuel maps.

I would also say that the main MT harness is a subset of the main AT harness, so no problem going from AT to MT

 

[Honcho]

or i just simply swap the ecu mode to manual by removing the R4 resistor?

Following on what Drew said, you can easily convert the AT ECU to MT by removing the R4 resistor. However, the AT heads in the engine use different cams and single-spring intake valve springs- running at 8,000 on these springs could break them or cause valve float (though knowing Honda, those springs probably would last a while before letting go). Thus, I'd be worried about bumping the rev limit before addressing that.

• If you keep your AT engine, then stick with the AT ECU- it will work fine with the MT with a couple of wiring tweaks.
• If you swap the MT double valve springs and cams, then just clip your R4 resistor and you're in business.
• While it is technically possible to burn a EPROM chip that raises RPM and keeps the AT fuel maps, it would be an "at your own risk" type of deal, since those valve springs were not designed for that RPM.

 

[stevecct]

Following on what Drew said, you can easily convert the AT ECU to MT by removing the R4 resistor. However, the AT heads in the engine use different cams and single-spring intake valve springs- running at 8,000 on these springs could break them or cause valve float (though knowing Honda, those springs probably would last a while before letting go). Thus, I'd be worried about bumping the rev limit before addressing that.

• If you keep your AT engine, then stick with the AT ECU- it will work fine with the MT with a couple of wiring tweaks.
• If you swap the MT double valve springs and cams, then just clip your R4 resistor and you're in business.
• While it is technically possible to burn a EPROM chip that raises RPM and keeps the AT fuel maps, it would be an "at your own risk" type of deal, since those valve springs were not designed for that RPM.

So there’s two solutions for me

1: keep at ecu and at ecu
2: change the camshafts and valve springs to mt, remove the r4 resistor

 

[stevecct]

Unless you have changed out the AT camshafts to the MT version, you should leave the AT ECU alone.

You can modify the RPM limit with a PROM burner using the AT fuel maps.

I would also say that the main MT harness is a subset of the main AT harness, so no problem going from AT to MT

Doubt if the spring are the same or not

 

[Honcho]

So there’s two solutions for me

1: keep at ecu and at ecu
2: change the camshafts and valve springs to mt, remove the r4 resistor

Yeah those are the two safe options.

 

[stevecct]

Yeah those are the two safe options.

Quick notes for the coming people

Honda NSX C30A Camshaft Spring Model​
AT		Parts No.	Qty	Factory
Front	In	14761-PR7-A11	6	NHK Spring
		14761-PR7-A12	6	CHUO Spring
	Ex	14762-PR7-A11	6	NHK Spring
		14762-PR7-A12	6	CHUO Spring
Rear	In	14761-PR7-A11	6	NHK Spring
		14761-PR7-A12	6	CHUO Spring
	Ex	14762-PR7-A11	6	NHK Spring
		14762-PR7-A12	6	CHUO Spring
MT		Parts No.	Qty	Factory
Front	In	14761-PR7-A01	6	NHK Spring
		14761-PR7-A02	6	CHUO Spring
	Ex	14762-PR7-A01	6	NHK Spring
		14762-PR7-A02	6	CHUO Spring
Rear	In	14761-PR7-A01	6	NHK Spring
		14761-PR7-A02	6	CHUO Spring
	Ex	14762-PR7-A01	6	NHK Spring
		14762-PR7-A02	6	CHUO Spring

 

[MotorMouth93]

The best way to run AT cams and valvetrain on an MT-converted car would be to take the AT fuel maps and rev limit and transplant them into the factory MT calibration, there's a lot of minor differences between the AT and MT logic particularly around idle control so this would allow the car to run properly without the expense of buying cams and valvetrain components. The timing maps are identical, it's only the fueling that is (very marginally) different.

 

[stevecct]

The best way to run AT cams and valvetrain on an MT-converted car would be to take the AT fuel maps and rev limit and transplant them into the factory MT calibration, there's a lot of minor differences between the AT and MT logic particularly around idle control so this would allow the car to run properly without the expense of buying cams and valvetrain components. The timing maps are identical, it's only the fueling that is (very marginally) different.

Ummmmm…. You mean running the mt map?

 

[MotorMouth93]

No. I mean making a custom chip that combines the MT and AT calibrations to allow the car to run properly with AT cams/valvetrain and a manual transmission bolted up. The AT valvetrain wasn't meant to handle 8000rpm+ hence lowering the rev limit, and the non-vtec lobes are larger and the vtec lobes are smaller so fueling should be adjusted accordingly.

 

[stevecct]

No. I mean making a custom chip that combines the MT and AT calibrations to allow the car to run properly with AT cams/valvetrain and a manual transmission bolted up. The AT valvetrain wasn't meant to handle 8000rpm+ hence lowering the rev limit, and the non-vtec lobes are larger and the vtec lobes are smaller so fueling should be adjusted accordingly.

at ecu rev 7500 only

 

[Honcho]

at ecu rev 7500 only

John is saying that the MT ECU contains several tweaks (mostly idle stuff) to make the car run smoother, so you should use a MT chip that swaps the AT fueling and AT rev limit (7500) to get the best outcome without having to open up the engine. Otherwise, it's best to stick with the AT ECU. @Big McLargeHuge is running his MT conversion that way and the car is fine, though I believe he plans to swap the MT cams and valve springs this summer.

 

[drew]

@MotorMouth93 you selling these AT map with MT idle prom chips by any chance?

 

[MotorMouth93]

I wasn't really planning on it but I could probably make them for $30-40. Basically the cost of the chip ($20 - the legit SST chips are discontinued and new old stock is now very pricey) and the cost of shipping. Or I could just email you a bin file if you have a way to write a chip yourself.

Honestly, I don't know that the benefits are great enough to warrant actually doing it vs just using the AT ECU unless you just like to tinker (or make other changes like converting to newer coils like Kseries or getting rid of EGR) and can't stand the idea of something being sub-optimal.

 

[stevecct]

John is saying that the MT ECU contains several tweaks (mostly idle stuff) to make the car run smoother, so you should use a MT chip that swaps the AT fueling and AT rev limit (7500) to get the best outcome without having to open up the engine. Otherwise, it's best to stick with the AT ECU. @Big McLargeHuge is running his MT conversion that way and the car is fine, though I believe he plans to swap the MT cams and valve springs this summer.

That means even changing the camshafts and springs to MT version.
A Ecu without R4 resistor wont make the car run smoothers?
The best solution of this case, is rewrite the map?

 

[stevecct]

I wasn't really planning on it but I could probably make them for $30-40. Basically the cost of the chip ($20 - the legit SST chips are discontinued and new old stock is now very pricey) and the cost of shipping. Or I could just email you a bin file if you have a way to write a chip yourself.

Honestly, I don't know that the benefits are great enough to warrant actually doing it vs just using the AT ECU unless you just like to tinker (or make other changes like converting to newer coils like Kseries or getting rid of EGR) and can't stand the idea of something being sub-optimal.

cool, let me know when you've developed them!

 

[YellowTwinTurbo]

That means even changing the camshafts and springs to MT version.
A Ecu without R4 resistor wont make the car run smoothers?
The best solution of this case, is rewrite the map?

I just did this conversion, changed all 4 auto cams to manual cams. Also, changed all single intake springs to double intake springs and all single exhaust springs. I still have my auto ECM and drove just fine on highway for 7hrs. I think RPM max out around 7ish RPM on my current auto ECM and we didn't touch the auto ECM R4.

 

[stevecct]

I just did this conversion, changed all 4 auto cams to manual cams. Also, changed all single intake springs to double intake springs and all single exhaust springs. I still have my auto ECM and drove just fine on highway for 7hrs. I think RPM max out around 7ish RPM on my current auto ECM and we didn't touch the auto ECM R4.

So basically you can the camshaft and springs to mt ver. But ecu remain AT

 

[YellowTwinTurbo]

So basically you can the camshaft and springs to mt ver. But ecu remain AT

So basically you can the camshaft and springs to mt ver. But ecu remain AT

yes for now since we were doing TM/WP, LMAs etc in that area. I will probably go with standalone ECU when I change the tranny.

 

[Honcho]

yes for now since we were doing TM/WP, LMAs etc in that area. I will probably go with standalone ECU when I change the tranny.

The car will run ok with the AT map and MT cams because in closed loop the ECU will compensate for the changed airflow via the O2 feedback. I would avoid open loop driving because there is less fuel in the AT map then the MT and you could run dangerously lean.

 

[MotorMouth93]

yes for now since we were doing TM/WP, LMAs etc in that area. I will probably go with standalone ECU when I change the tranny.

Unless you're boosting or having some problem with the stock ECU a standalone will be a few thousand dollars minimum for no gains in power.

 

[YellowTwinTurbo]

Unless you're boosting or having some problem with the stock ECU a standalone will be a few thousand dollars minimum for no gains in power.

Yes, my plan is to boost in the near future.