1974 Datsun 260Z, RB25DET, MS1/E

Nissan, Infiniti, Datsun
510rob
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1974 Datsun 260Z, RB25DET, MS1/E

Post by 510rob » Mon Oct 01, 2007 12:25 am

First and foremost, I want to thank Bruce, Al, Eric, Phil, Lance, James, Ken, Glen, and all of the other talented and intelligent people from the forums and community, including the foundations started in the DIY-EFI and EFI332 days so many years ago (I've been a very long-term lurker!)

Being able to fuel inject a motor like an RB25DET with an open-source community developed engine management system is a dream come true. To be in the car, logging, tuning, and living the reality of such a successful group project is, in one word, electrifying! I see the completion of this project as another victory for the whole Megasquirt community! Enough victory celebration and champagne, let's get on with some details of the car and MS...

Car's Owner : Ray S.

MS build and install = Robert F.

1974 Datsun 260Z with a Nissan RB25DET controlled by MS1/E-029v

The JDM motor set came "complete" with a slightly fubar'd wiring harness and the incorrect stock ECU. I was contracted to "solve the problems and make it all work" - I made a new CAS wheel, rewired everything, and set the car up with a nice Megasquirt system. The car won 1st place in the "Modified Z-Car" class at the 2007 All Nissan meet in Vancouver. Yay! All that fiddle-farting to keep the wiring and installation clean, neat, and tidy paid off in the end!

About the MS stuff (that's what you really want to know about, isn't it?)

MS DETAILS...

V3.0 MS basic kit from Glen's Garage, running MS1/E-029v code.

IGNITION : Six VB921s running the stock COP ignition coils - keeps the install very clean. The VBs are wired to Spark A, B, & C in pseudo wasted spark mode. I did this because I wanted to have knock detection and ignition retard capability... (see next blurb on knock sensing for more details). We suffered from a nasty ignition miss near the torque peak when running 0.038" plug gaps, but when we dropped the plug gaps down to 0.032", all the ignition problems cleared up nicely.

KNOCK SENSING : The Spark_F/Knock_In pin can be used as either the Spark_F output, or as the Knock_In line, but not both! If you want to use knock sensing features, you can't use 6-channel ignition!!! The RB25DET has two knock sensors, so I used a pair of Boris' nice little KnockSenseMS boxes. (note - the knock-induced ignition retard isn't completely implemented yet - our street tuning sessions have been rained out by Vancouver weather!)

VARIABLE CAM TIMING : The variable cam timing solenoid is driven by a TIP120 on Output2 (X5 / JS3). I set the solenoid for 4500rom and 200rpm hysteresis. This might be wrong, but it is a starting point for now. If anyone knows what the "correct" VCT rpm setting should be, please let me know.

BOOST CONTROL : The boost control solenoid is driven by a TIP120 on output ___ ??? (not implemented just yet - more bugs to sort out elsewhere)

IDLE CONTROL : The idle air solenoid is driven by a TIP120
on output ___ ??? (not implemented just yet - more bugs to sort out elsewhere)

FAN CONTROL : The fan relay is driven by one of the 2N2222s used for one of the original LED outputs.

TACH OUTPUT : The tach is driven by a 2N5551 installed in one of the transistor spots for the original LED outputs. I used the higher voltage transistor in case I had to install an external choke. I didn't need any choke, so the 2N2222 would have been fine.

CAS SENSOR : The biggest stumbling block for the install was the CAS sensor - I made a new proprietary CAS opto interruptor wheel for the RB25DET, and it works great! If there is any demand for these wheels, I might have some more made, then offer them to the community for a modest/fair price - it's good for karma!

After a few initial teething issues, everything is running like a charm. I haven't set up the parameters for the boost control yet, nor the parameters for idle control. The rainy weather seems to have come to Vancouver, so that might have to wait until next year...

Post questions if you'd like...

I will try to post some pictures of the car elsewhere and link them here.

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hightuner
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Post by hightuner » Tue Oct 02, 2007 12:42 pm

Hey congrat on getting the Rb running !!

Sequential COP EDIT:oupps read too fast
Vtc
CAS opto interruptor

geez i have to learn from you
good job :D
Nissan Vq35de 02 (maxima96) :RTFM:

510rob
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Post by 510rob » Tue Oct 02, 2007 6:26 pm

Thanks for the thanks - it's about time us MS'ers cracked the RB series code so to speak. Anyone else that needs some help with RB engines can PM or e-mail me, and I'll share what I can.

I made a little video compilation with pictures from the build and install. The video also shows the car's maiden voyage (into the driveway). I figured that would be one of the best pieces of footage to capture. Unfortunately, it's the only video I've grabbed of the car running because every other time, I've been sitting with a computer in my lap. I will record some more video of the car the next chance I get, and post it on Youtube. Until then, here's the first video...

http://www.youtube.com/watch?v=AJ3Wya2Hzzk

Does anyone have any suggestions for a better turbo for this engine? The owner's goals are not dyno queen, and more like fun weekend car/autocross car. I was thinking it would be a good motor for a T04E-50 trim compressor with the T3 "Stage3" turbine, with a 0.82 A/R housing.

midnightsliding
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Post by midnightsliding » Mon Nov 05, 2007 11:51 pm

man this is sweet im looking into going this route with my RB25.

PUMPISH
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Post by PUMPISH » Fri Feb 15, 2008 3:16 pm

Looks great!!!!

Did you find some turbo?
How much Hp are you searching?

Do you have space enough for twinentry manifold with twin WG pipes?

Thanks! /Roman

Krita
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Re: 1974 Datsun 260Z, RB25DET, MS1/E

Post by Krita » Sat Apr 12, 2008 8:05 pm

to calculate the vct activation point run a full pass on a dyno with vct deactivated then a full pass with it activated where the power curves cross over is the point of activation possibly minus a few rpm to cater for the time it taks for the cam to move.

hoe that makes sense, you may need to re tune on each pass to find the optimum cros over point.

note: this if for a crude rpm based switchover, dont ask me how to set it up dependant on engine load......anyone????

devojet
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Re: 1974 Datsun 260Z, RB25DET, MS1/E

Post by devojet » Mon Jun 23, 2008 3:26 am

Could you please post some pictures and details of your CAS wheel? I might be interested in one in the future.
A shed is never big enough.

50trims
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Re:

Post by 50trims » Sat Nov 22, 2008 11:27 am

510rob wrote:Does anyone have any suggestions for a better turbo for this engine? The owner's goals are not dyno queen, and more like fun weekend car/autocross car. I was thinking it would be a good motor for a T04E-50 trim compressor with the T3 "Stage3" turbine, with a 0.82 A/R housing.
well that turbo you mentioned has a great compressor map and is good to almost 500 whp on race gas and alot of boost id say it would be a good choice the only thing i would change is that since that turbo is used by a lot of 1.8l 4 cylinders i would get it just like you said exept with a stg5 wheel

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Re: 1974 Datsun 260Z, RB25DET, MS1/E

Post by abustiffy » Sat Nov 22, 2008 10:46 pm

For turbo I would suggest a full t4. t04e p trim .58 exhaust and a 60 trim compressor. I ran this combo but with a .70 exhaust housing on a 7mgte (3l) and loved it. The smaller housing will help with spoolup. The 50 trim will also work well but at the lower pressure ratios you will be at compared to a 2 liter I feel the 60 is a better wheel.

67greenio
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Re: 1974 Datsun 260Z, RB25DET, MS1/E

Post by 67greenio » Sat May 23, 2009 3:14 pm

May I ask what are your AE,timing, constants, etc...

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