Lean out on a supercharger with Fensport pulley?

[Pineapplehat]

Hi guys, interested in buying a bigger pulley for some extra boost but I've heard accounts of 4AGZEs encountering lean running in higher rpm when a bigger pulley is used, from what I tell it's more so the USDM models rather than the JDM ones but if anyone's had some first hand experience with it, was it a noticeable issue or non-existent? I've been looking at a piggyback system for the ECU like an E manage Ultimate or something to cure it but they aren't cheap so I'm wondering if it's really necessary or not? Cheers!

[Ben]

Mine ran fine with a 175mm pulley and standard ECU. If anything I think they err towards running slightly rich, but I'm sure someone more knowledgable will be along shortly

I assume you're aware of the corresponding ABV mod that's necessary to make use of the extra boost?

[oukie]

Mine's had the pulley mod, done by woodsport, including ABV mod, I'm interested in this thread, mainly to see where it goes.

[Pineapplehat]

Mine ran fine with a 175mm pulley and standard ECU. If anything I think they err towards running slightly rich, but I'm sure someone more knowledgable will be along shortly

I assume you're aware of the corresponding ABV mod that's necessary to make use of the extra boost?

Yeah I know about the corresponding ABV mod done with bigger pulleys but I know little about what fuelling is like once the boost is upped. I've never heard anything of massive differences apart from the US models which is why they have the gruntbox but we (with the JDM models) don't have an equivalent I assume.

[Lauren]

You need to block off the ABV. Swopping the VSV's round is not the way to do it.

There's not an issue as such with it running lean.

I ran a big pulley with ABV blanked off with no issues and did at least 30 trackdays in it.

[PW@Woodsport]

Agreed, there will be no lean running on a big pulley kit with ABV mod, Oukie what max boost do you see? Is the car fitted with a boost gauge?

[Ben]

If it helps, mine with a boost gauge ran about 1 bar (from memory).

[oukie]

Agreed, there will be no lean running on a big pulley kit with ABV mod, Oukie what max boost do you see? Is the car fitted with a boost gauge?

No boost gauge fitted, is this a must ? Paul my SC is Munters old one (I believe you did the pulley conversion)

[SuperRedMR2]

When my mate was running his mk1a 4agze conversion he was at 12 psi with the oversize pulley.

[PW@Woodsport]

I think a decent boost gauge is a must on a forced induction car, yep i fitted the big pulley on that one, so it will also have my upgraded steel idler on there too.

[oukie]

Any specific, make model gauge etc,

[Lauren]

You can buy TRD ones from the US, though they read in PSI rather than Bar.

The boost gauge is more useful to determine when you are getting heat soak. But really on the road unless you're hammering it, it isn't a big issue. Much more of an issue on the track of course.

When it starts to heatsoak the boost pressure goes up of course but the air density goes down and along with it, the performance.

[PW@Woodsport]

I use this one on my SC, mainly because it has a wide scale on the digits for accurate reading and it has the word "supercharger" on it, which is cool. I have that on a pod just above the wiper switch on the binnacle.

http://www.burtonpower.com/revotec-gaug ... s-psi.html

[greglebon]

That's the one I had in my Mk1 "NightHawk" , Paul...looks the nuts, doesn't it..?

To O/P, As for lean-ness, shouldn't be an issue with the sizes of pulley being talked about here...

The problem, assuming decent intercooling, is more likely to be the actual metering of the fuel, as, iirc, under certain high-boost / temp conditions, the ECU opens the injectors 100% in an attempt to prevent detonation occurring..?

This was always a grey area for me, which is why a standalone is really a must for decent, safe power increases with 4AGZE's....

Anything else is a bit of a compromise, tbh..?

[Lauren]

The biggest issue is intercooling.

Chris is unlikely to track his car I would say, so there is no need to worry about a piggy back ECU or a standalone one. Many, many people have run JDM 4AGZE's with big pulleys without issues for years.

I used my old car a lot on track, with no issues, the intercooling I had to sort though, that was the problem, but there were no other issues and rolling road runs checking the fueling did not reveal issues. I had to use a rising rate fuel pressure regulator as mine was a conversion so NA fuel pump, though it was the NA pressure regulator that was the issue, but obviously Chris won't have this issue.

A JDM AW11 4AGZE will make 180bhp with a bit less torque. I had a later spe GZE so managed 187bhp with a better torque curve than the earlier engine as found in the AW11 SC.

[oukie]

The biggest issue is intercooling.

Chris is unlikely to track his car I would say, so there is no need to worry about a piggy back ECU or a standalone one. Many, many people have run JDM 4AGZE's with big pulleys without issues for years.

I used my old car a lot on track, with no issues, the intercooling I had to sort though, that was the problem, but there were no other issues and rolling road runs checking the fueling did not reveal issues. I had to use a rising rate fuel pressure regulator as mine was a conversion so NA fuel pump, though it was the NA pressure regulator that was the issue, but obviously Chris won't have this issue.

A JDM AW11 4AGZE will make 180bhp with a bit less torque. I had a later spe GZE so managed 187bhp with a better torque curve than the earlier engine as found in the AW11 SC.

Don't mean to thread hijack, I'm very interested in the points the op raised.

Your spot on Lauren,


I won't be doing track days, although I have wondered about the intercooler, interwarmer as I've heard it mentioned before, I was thinking maybe some sort of spal fan set up could help get heat out quicker.

[Pineapplehat]

The biggest issue is intercooling.

Chris is unlikely to track his car I would say, so there is no need to worry about a piggy back ECU or a standalone one. Many, many people have run JDM 4AGZE's with big pulleys without issues for years.

I used my old car a lot on track, with no issues, the intercooling I had to sort though, that was the problem, but there were no other issues and rolling road runs checking the fueling did not reveal issues. I had to use a rising rate fuel pressure regulator as mine was a conversion so NA fuel pump, though it was the NA pressure regulator that was the issue, but obviously Chris won't have this issue.

A JDM AW11 4AGZE will make 180bhp with a bit less torque. I had a later spe GZE so managed 187bhp with a better torque curve than the earlier engine as found in the AW11 SC.

Don't mean to thread hijack, I'm very interested in the points the op raised.

Your spot on Lauren,


I won't be doing track days, although I have wondered about the intercooler, interwarmer as I've heard it mentioned before, I was thinking maybe some sort of spal fan set up could help get heat out quicker.

Intercooler is another good point actually, I've got a fan mounted under mine which seems to help with normal to spirited driving but after long runs the heat soak is still definitely noticeable. Do the Tom's style air scoops I've seen on some MK1s make a reasonable difference?

[oukie]

That answers it then, 12" spal going under mine. Possibly some custom ducting also.

[Lauren]

You will find with a fan mounted under the intercooler, that it actually works against you over around 50mph.

Fans are really only any use for aiding cooling when you're at a standstill.

[oukie]

You will find with a fan mounted under the intercooler, that it actually works against you over around 50mph.

Fans are really only any use for aiding cooling when you're at a standstill.

Does that depend on sucking or blowing? Oh err