Jump to content
SAU Community

Recommended Posts

I am now close to assembling my RB26 lump. Spec is as follows:

New N1 block, Tomei cooling channel forged pistons @ 86.5mm bore. Tomei forged rods, Farndon billet crank at stock stroke (same as HKS steel crank), Tomei high capacity oil pump, Tomei 280 duration cams with 10.8 mm lift, stock valve sizes, in new RB26 head casting, mildly ported and matched to manifolds. Intake side is stock plenum with 50 mm (bored out stock) throttle bodies. I will be running a single TO4 family turbo, and aiming for 600 BHP max. I will be running Motec M600 or M800 ecu. I want to ideally ditch an AFM and run MAP sensor system. has anyone real world experience of a well mapped single turbo engine of broadly similar spec on a MAP sensor system? How was drivability? Throttle response? Do you regret not sticking witha MAF sensored system?

Usage for the engine is track days in a stripped out R33 GTS-t bodyshell, with a possiblity of dropping in an R33 GTR rolling chassis at some future point for some fun on the roads.

Thanks.

I run a single and a Motec M800 on my 32.

The idle, drivability, Throttle response etc will only ever be as good as your Tuner and support systems. If you do go a M600 or M800, spend the extra money on someone who knows how to tune them. Even If that means flying someone over.

I am really happy with my result. However nige & karlos spent a long time getting it perfect. Personally i hate those pesky AFM's :P

:

N1 block has 87 mm bore so how are you using 86.5mm pistons

Well, it's a brand new, in the Nissan box, N1 block, with N1 part number and it's a 96 mm bore. So not sure how to respond to that... :) I chose 96.5 to allow at least one more bore out of it for wear purposes, or a minor whoopsie.

I should state up front we have 2 X GTR's running Motecs, one M600 and one M8. And I have used Motec's of all types on race cars for many years.

Personally i hate those pesky AFM's

Why?

It can't be power, I have seen an RB27 with 2 X Q45 AFM's make 1100 bhp.

It can't be speed, I have seen a 170 mph TS on a GTR with AFM's

It can't be time I have seen an 8 second pass..........

It can't be tuning, there is simply no better way to match fuel to airflow than by measuring the airlfow. Everything else is a compromise.

The idle, drivability, Throttle response etc will only ever be as good as your Tuner and support systems. If you do go a M600 or M800, spend the extra money on someone who knows how to tune them. .......nige & karlos spent a long time getting it perfect.

And that's the problem, I can get a car to run ALMOST as "nice" on the Motec's as I can on the Power FC, but it takes me many many hours (remember I have never claimed to be a good tuner) to tune the stuff that the Power FC comes pre programmed with. Motecs have nothing, you have to start from scratch.

An example, I can plug a Power FC into a suitable RB, drive it to the dyno and tune it for 425 rwkw in under 2 hours. All up cost (PFC & tuning) less than $1,600. It would take me 3 days to do the same with a Motec. I have not seen any evidence of achieving more than a handfull extra power with the Motec, but one thing is for sure I would have to get the car back a couple of times to fine tune the hot run, cold start, aircon compensation, idle quality and cold run that the Power FC has standard. All up cost (Motec M600, sensors & tuning) more than $5,000, depending on the enabled options.

The question for me is "can I spend the extra $3.5K" on something that will give me more bang for my buck?

:P

PS; Chris, if you want to know more about setting up the Motec, please just ask.

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now


  • Similar Content

  • Latest Posts

    • Have a look at that (shitty) pic I posted. You can see AN -4 braided line coming to a -4 to 1/8 BSPT adapter, into a 1/8 BSPT T piece. The Haltech pressure sender is screwed into the long arm of the sender and factory sender (pre your pic) into the T side. You can also see the cable tie holding the whole contraption in place. Is it better than mounting the sender direct to your engine fitting......yes because it removes that vibration as the engine revs out 50 times every lap and that factory sender is pretty big. Is it necessary for you......well I've got no idea, I just don't like something important failing twice so over-engineer it to the moon!
    • Yup. You can get creative and make a sort of "bracket" with cable ties. Put 2 around the sender with a third passing underneath them strapped down against the sender. Then that third one is able to be passed through some hole at right angles to the orientation of the sender. Or some variation on the theme. Yes.... ummm, with caveats? I mean, the sender is BSP and you would likely have AN stuff on the hose, so yes, there would be the adapter you mention. But the block end will either be 1/8 NPT if that thread is still OK in there, or you can drill and tap it out to 1/4 BSP or NPT and use appropriate adapter there. As it stands, your mention of 1/8 BSPT male seems... wrong for the 1/8 NPT female it has to go into. The hose will be better, because even with the bush, the mass of the sender will be "hanging" off a hard threaded connection and will add some stress/strain to that. It might fail in the future. The hose eliminates almost all such risk - but adds in several more threaded connections to leak from! It really should be tapered, but it looks very long in that photo with no taper visible. If you have it in hand you should be able to see if it tapered or not. There technically is no possibility of a mechanical seal with a parallel male in a parallel female, so it is hard to believe that it is parallel male, but weirder things have happened. Maybe it's meant to seat on some surface when screwed in on the original installation? Anyway, at that thread size, parallel in parallel, with tape and goop, will seal just fine.
    • How do you propose I cable tie this: To something securely? Is it really just a case of finding a couple of holes and ziptying it there so it never goes flying or starts dangling around, more or less? Then run a 1/8 BSP Female to [hose adapter of choice?/AN?] and then the opposing fitting at the bush-into-oil-block end? being the hose-into-realistically likely a 1/8 BSPT male) Is this going to provide any real benefit over using a stainless/steel 1/4 to 1/8 BSPT reducing bush? I am making the assumption the OEM sender is BSPT not BSPP/BSP
    • I fashioned a ramp out of a couple of pieces of 140x35 lumber, to get the bumper up slightly, and then one of these is what I use
    • I wouldn't worry about dissimilar metal corrosion, should you just buy/make a steel replacement. There will be thread tape and sealant compound between the metals. The few little spots where they touch each other will be deep inside the joint, unable to get wet. And the alloy block is much much larger than a small steel fitting, so there is plenty of "sacrificial" capacity there. Any bush you put in there will be dissimilar anyway. Either steel or brass. Maybe stainless. All of them are different to the other parts in the chain. But what I said above still applies.
×
×
  • Create New...