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The mkiv Supra Owners Club

Advice on running 1.1 bar.


Andrew

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Fitted a boost gauge at the weekend, so now I can see exactly what I'm running.

 

Sunday was fairly warm and the gauge showed 1.05 bar, this morning I ran 1.1 bar as it was fairly cold.

 

I was told my Sup was full decat but I have discovered that it has the first cat still in, this is obviously restricting the boost a bit, but I'm happy running 1.1 bar.

 

Do I need to start looking at cooling things down with an intercooler or an intercooler pipe upgrade, or can I run 1.1 bar safely as it is?

 

Would I need to upgrade my fuelling system to a UK spec pump? UK injectors?

 

Also do MKIVs have steel head gaskets?

 

 

 

Thanks,

Andrew.

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Do I need to start looking at cooling things down with an intercooler or an intercooler pipe upgrade, or can I run 1.1 bar safely as it is?

 

I'm pretty sure that a lot of people on here are running 1.1 bar without an FMIC.

I think the pipes are more susceptible to splitting when running increased boost and this risk will obviously be higher if they've never been changed before.

Hard pipe upgrade kits are available but not cheap from what I've seen.

 

Would I need to upgrade my fuelling system to a UK spec pump? UK injectors?

 

There's a recent thread which discusses at length the various fuel pump options here:

 

http://www.mkivsupra.net/vbb/showthread.php?s=&threadid=6915&highlight=fuel+pump

 

Again though I think lot's of owners are running your boost levels using the standard one.

 

Also do MKIVs have steel head gaskets?

 

Don't if the head gasket is steel but the MKIV is not known for suffering BHG so you should'nt need to worry about that at this stage.

 

HTH

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Originally posted by SMW

Hard pipe upgrade kits are available but not cheap from what I've seen.

 

I have been looking at some this morning, and you're dead right £350 isn't cheap. Look good though ;)

I read that link on the pump upgrades, interesting read.

Thanks for the answers just the ones I was looking for, I very rarely run 1.1 bar and have the warning set at stock 11 psi so try to lay off the pedal when I hit that.

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The Multi Layered Head gasket seems to allow people to run upto 2bar without it blowing...Toyota did a very good job with it!

 

If you want to upgrade your cooling without impacting on your insurance I would suggest you get a Chris Wilson stock replacment IC with ERL or similar Water injection. Hard Pipes are not necessary...they just look pretty! :)

 

A UK spec/TDI fuel pump would also be worth while.

 

How have you decatted it?? An HKS Mid-pipe? Or a CW pipe?

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Well the head gasket taking 2 bar puts my mind at rest, as I now plan on staying at 1.1 bar.

Toyota obviously learnt a lesson from the MKIII, I modded mine to around 300bhp and shortly after it was sold it went BHG, told him to fit a steal HG and not to boot it until he had :innocent:

 

The prices I'm getting on water injectors is around £300, not bad if they do a good job.

 

I have been toying with the idea of an upgraded fuel pump, as they seem a cheap upgrade. Would I need to upgrade to bigger injectors too?

 

AFAIK it has a Trial exhaust mid pipe, replacing the 2nd cat, looks like a 4 inch pipe.

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Well with that mid pipe if you take out the other cat you will face severe overboosting.

 

So I would do as you've suggested and cool the charge as much as possible.

 

You won't need to replace the injectors yet. Just get a better one which pumps at a higher pressure. The UK spec/TDI one will be fine for this. A fuel dampner bypass may also be worthwhile. Ask TDI/CW/Leon or Paul Whiffin for one of these.

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Originally posted by Alex Holdroyd

Well with that mid pipe if you take out the other cat you will face severe overboosting.

 

That's what I was afraid of Alex, fortunatly cat one still remains in place and I won't be taking that out following your advice and others.

 

The fuel pump and cooling mods will follow maybe later this year, just glad to hear I'm safe with my current set up.

 

Thanks again for all the info.

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Originally posted by gwillson75

Oh, and removing that cat will make it louder.

 

Well you know the cat has to come out now :)

 

Interesting to know the restrictors can be set to what boost you want, would this be something easy to alter yourself if you wanted to up the boost?

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You can specify what Boost you want to have with the restrictor ring although its not 100% accurate, i said i wanted no higer than 1.2 Bar, and mine boosts to 1.22 so its fairly accurate.. When i get Water Injection and a few other things i''l file out the restrictor ring a bit to maybe 1.25Bar or 1.3Bar

 

As for the fuel pump being necessary, its advised due to more fuel required for the upgrade can account to detonation at high revs.

Upgraded Spark Plugs solved mine when i 1st raised the boost...

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Yer it is, he doesnt live far from me......I know from EGT temps without the CAT that on full thrash i can reach 920 degrees darent think about what this would be with CAT in place, it did reach 980 once when i was running 1.4Bar for a bit... :blink:

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