Datsun Roadster Forum-311s.org

Also, just because you cannot use the Autech header, doesn't mean you cannot make the motor breathe.. I used a local fabricator, and had a header made that fit the roadster engine bay. And I think it is decent looking myself..

so is the s15 autech ECU hard to crack ? ... will the tuning down for 91 reduce the HP or how will it affect the engine ?

sorry for the newbie questions, i'm just new in this roadster and sr world.

BTW RCMike those headers are gorgeous !!! what did that work cost ? .. if you don't mind me asking.

Truly amazing you can run that kind of compression Mike. A testament to how far engine management has come. My mega jolt allows me to (barely) run 92 on my U20 at 11.7 to 1, but 13 to 1 is wild. The point of detonation varies engine design to engine design, but regardless you're still compressing the fuel very hard, and detonation is not due to a spark event (i.e. timing) but compression. I highly doubt a U20 would live long at that compression regardless. Very impressive.

As promised, here are some pics with the Autech header trying to go into place. I don't have the tranny mount in and it might affect somewhat, but you can see some major frame interference beyond the issue of the steering column.

RCMike wrote: I am planning to shift it to a flex fuel system soon, to allow the motor to use higher octane fuel to make more power. Our tuner wanted e-85 the minute he heard the motor was close to 13:1.. But I told him it had to be useful for long drives through back country, where 'fuel' might not be available. So he is really happy that I want to go to flex fuel. Should be interesting to see what the fuel will do to power..

I've been wanting to go flexfuel too but I'm not sure I can do it with Autech ECU. New flexfuel cars can do either since the sensor measures the amount of ethanol in it. Flexfuel is cheaper too. It isn't cheaper when compared to regular (given the loss of fuel mileage with E85) but it is when compared to premium. I have access to 93 octane here in Ohio, but would love to do flexfuel as well. I thought about going megasquirt to try and do that, but the guy that did my LSx told me to get it running first with the Autech ECU, and then try to do other things. So that is my current route.

If anyone has any recommended gurus to tell me how to get to E85 sooner, I'm all ears!

RCMike wrote:Also, just because you cannot use the Autech header, doesn't mean you cannot make the motor breathe.. I used a local fabricator, and had a header made that fit the roadster engine bay. And I think it is decent looking myself..

What diameter are the primary tubes in your car?

I think I remember 1 7/8"? It has been a long time..

any photos on how far back the autech's 6 speed shifter sits ?

You can look at my build thread over in the member's ride section for the autech engine/tranny mounted on the frame.
http://www.311s.org/phpBB3/viewtopic.ph ... 4&start=30

The 6-speed is only 10mm longer than the standard SR 5-speed and the shifter works out in the 1600 position just fine.

Michael

Right on! thanks guys. I ended up taking my roadster to schaders to get the SR swap done, I hope all goes well.
Thanks again guys.

Watch out with the efi tuner talk
Who are you getting to do it?...no dont say
Any tampering with the fuel setting counts anymore
I got indited in 97 at an Eagle dealer for using a different # efi reflash rom pac ( it was part of the update ,just wrong for the ser#) ..scared the crap out of me

Redroadster , So you also have an autech version? Yea that programing has me a bit worried.

I think redroadster is concerned, in general, with the legality of modifying ecus.

In our case, we don't have emission-controlled cars and we are usually improving emissions drastically so I don't see a legal issue.

My Autech was missing the ECU so I converted to a coil-on-plug system and used a haltech Platinum Pro Plug and Play ECU. Haltech also gave me a solution if you want to continue to use a distributor too. Let me know if you are interested and I'll dig out the email from Haltech.

Even though I was forced to go aftermarket, there are plenty of advantages. 1) You can tune it to match YOUR car modifications and altitude; 2) You can tune it to handle lower octane fuel; 3) It removes factory speed controls; 4) You can convert to flex-fuel.

I'm sure there are more advantages. Disadvantages . . . cost.

Shannon

Ok cool, Thanks Shannon. I appreciate it, I will get back to you when I hear from the shop.