1JZ 260KW+ Recipe. Might Need Some Help :)

[chrisrundell69]

manual mate. r154

[MR 1JZ]

yeah...simon will have to whack in some 440's before we tune it

[chrisrundell69]

tr44 looks the go, depending on what soarer dood says about t70, so the shopping list begins
tr44
440cc injectors
SAFC II
FCD
and a wastegate

[MR 1JZ]

SAFC II negates the need for an FCD...they wont work together anyway...as they both bend the map sensor voltage

[chrisrundell69]

shows what i know doesnt it well thats 1 less thing to buy

[chris davey]

AFAIK the safc will increase boost cut by a few psi if you are pulling fuel out of it but I thought you still needed the SAFC. If the FCD clamps the MAP signal at 4.32v (13.7psi IIRC) then you pull 5% fuel out of it then I would think that the MAP signal would then be reduced further. I am sure this is how people in US were running single turbo setups with nothing other than a SAFC and FCD to make 320 oddrwkw on our dynos. 25psi+

[MR 1JZ]

ahhh really...but if you use an FCD you cant put any more fuel in can you?

[chris davey]

nope, have you use bigger injectors.

Not above the FCD clamp point. So if you had no FCD you could run maybe 16psi instead of 14.7psi before boost cut if you are pulling fuel out. If you have a FCD the map wouldn't ever see 14.7psi so you are limited to whatever duty cycle is run at just before the clamp voltage. So if you run bigger injectors it "could" be ok. People in the US seem to like to use 2jz map sensor, 550cc injectors, Safc and FCD. Can work ok as I said but a full ecu would do a more refined job if tuned well.

[Danners]

Good thread - I'm looking at using a TR44 also. Already have the 440cc injectors and SAFCII

I still however don't understand why the US guys use the 2J Map sensor, as tests prove that they are identical to the 1J jobby. Did someone just make up the wives tale one day and everybody else followed it?

[chris davey]

probably.

I don't know much about 2j's so won't comment.

Hearsay on the internet is quite common!

[MR 1JZ]

stupid americans are quite common!

fixed........

[BMWTurbo]

I'd be interested in the results to show the 1jz reads the same as the 2jz MAP sensor.

My test's with one of each showed the 1jz maxed at around 16psi and the 2jz around 19psi... Maybe I had a dud 1jz sensor?

[ReQuieM]

Do a search, was kicking around a few weeks ago.

[2JZR31]

I keep telling everyone that you don't need a FCD if you are using a MAP sensor sender bender like the SAFC. I just built a jaycar DFA and want to test it out on my brothers 1JZ.

You can use it to get rid of the fuel cut totally. Some guys on the soarer forum reckon it causes issues, but the only issue I have seem is wheelspin. The only time it will cause issues is when you are running out of fuel then try to use the SAFC to remove the fuel cut. Or if your tuner is a moron. It will advance timing but that does not seem to cuase any issues.

You can work it out like this.

Max map sensor resolution voltage divided by fuel cut voltage gives the SAFC percentage which will remove the fuel cut altogether.

The SAFC even has a screen where you can monitor the map sensor voltage. I used compressed air to load up my 2JZ sensor. It went to 4.87v @ 1.21 bar according to the SAFC. Fuel cut is around 4.35V

So 4.87 / 4.35 = 1.2
That's 12%

So if you set the SAFC to minus 11% you will raise to boost cut to approx 1.2bar with a 2JZ map sensor which is a lot safer that having no boost cut!

If you set it to minus 12% you will never hit the fuel cut just like a FCD. Since the map sensor will never go above 4.87v (even if you run 30psi) and you are taking away 12% the output can never go above the fuel cut voltage of 4.35v. So when you fit larger injectors you normally minus between 15-20% which means you will not have a fuel cut anymore.

We have my mates T04Z aristo set up with minus 11% and it runs 1.2bar and still has a fuel cut. It has stock injectors, 044 pump and sard PFR with 50psi base pressure.

I am going to fit 550 to my 2J and see how it goes with the SAFC.