I've made a few more tweaks to my B210. I've installed the 3.54's and switched to a synthetic 75W-90 gear oil this time around. I've also removed the 175/70R13's and mounted a set of 155/80R13's. I am currently lowering the suspension a bit this week as well. Here in the US, we have 10% ethanol blended into our gasoline. This hurts fuel mileage, but there are a few rare stations here and there that sell 100% pure gasoline [no ethanol]. It costs about 15 cents more per gallon. This is what I use for best mpg's.

I am looking forward to testing my car now with the 3.54's in it. I am wondering if there will be any gain in staying in 4th gear when cruising under 50 mph and really going for the big mpg numbers. As many of you know, in our transmissions 4th gear is not really a gear. You are simply locking the mainshaft for a straight 1 to 1 ratio and sending the power flow straight through the transmission and therefore bypassing all of the helical cut gearsets. In 5th [or any other gear], there is a bit more drag because the power flow through the trans has to go through both the main and countershafts, and through the gearsets themsleves.

Earlier in this thread David said that I should be shooting for 70 mpg, and not 50. It now seems that he was right. :)

Mike

Hmm... getting over 60 mpg. Now it is getting interesting.

I've always heard that the highest gear should be used for maximum fuel economy. So I would expect 5th -- even if going through the countershaft -- will result in better economy than direct-drive 4th. You reduce engine pumping and friction losses dramatically at lower RPM.

Let us know how the theory tests out.

Mike,

Are you still looking for anything from an A13 74 B210 engine? Like the single belt pulley? I recently parted one out and have a complete engine.

I saw these plugs on ebay and they really jogged my memory.



I forgot all about the fact that the MPG model B310's had these four grounding tip spark plugs from the factory. Can anyone venture a guess as to why these were spec'ed for the MPG models? Technically, how exactly do the extra electrodes help?

Mike

Quote:Sorry for the late reply. For some reason I did not get an email notice as usual, as I am subscribed to this thread. I ordered a single groove pulley through a dealer and they are on back order from Japan. So I should get one eventually [hopefully].

Thanks for the heads up and if I was anywhere on the west coast, I'd jump on that A13. Yes indeed I'd like to have one [or an A12A also].

Mike

Quote:I'm looking at the 1981 Factory Service Manual. It says
USA BPR5ES-11
Canada MPG BPR5ES-11
Canada except MPG BPR5ES

Where did you see it was four-plug?

Quote:David,

The Nissan part number is 22401-H7285.

Although the picture doesn't match the part number, I saw a them HERE. They list them as being for the GFU model. I don't remember what GFU stands for, but I thought they had something to do with the MPG models?

More ads can be seen for these HERE and HERE.

The info is a bit confusing, as some say all from '76 - '82, when another says just '79 A14.

Mike

I trust the Nissan service manual which lists the normal plugs. Sure you can use the fancy plugs but it won't make any difference.

Quote:David,

Here are the factory plugs I'm referencing.




I don't have a 1981 factory manual, but I found them in the 1980 Datsun 210 manual.




Does anyone know what the "FU" model designation stands for?

FU Engine is the high MPG engine (50 mpg in B210, 47 MPG is B310). "F" means five-speed, and "U" means United States. All five-speed models were fuel-efficiency motors, not performance models.

Which manual do you have? I'm look at the 1980 Datsun 210 factory "Service Manual" (Nissan, Feb. 1980), and it lists BPR5ES-11 for US, and BPR5ES for Canada.