Janspeed turbo boost

[glyn]

I've just fitted a boost gauge to my car which has a Janspeed turbo and i want to make sure everything is running hunky dorey so can anyone tell me what the boost gauge should be reading, at tick over its at .6 vac and am i right in thinking that at around 60mph it should go up to between 0.5 and 1 bar boost?
Is it possible to turn the boost up on these?
Plus are there any serviceable parts on the Janspeed turbo that might need looking at?
As you can probably tell this is my first motor with an aftermarket turbo on.

[Mr.G]

Glyn,

What kind of set up do you have, are you running efi or carbs?

If you have a pop off valve on the end of your J pipe going to the turbo you can fit an adjustable pressure relief valve. Before you up the boost I'd recommend you fit an Air Fuel Ratio Gauge to make sure you are not leaning out. You shouldnt increase the boost too much or you increase the chances of detonating, I would also recommend you fit an intercooler. I have for sale an alloy radiator/intercooler set up that was used with a Janspeed system which may be of use, it fits in place of your radiator.

With regards to serviceable parts - the pop off valve usually leaks, the rotomaster turbo may need a rebuild and I'd recommend replacing gaskets. You may have to get gaskets specially made, if you need a contact let me know and I will try and dig you out a company i have dealt with before, all they need is a pattern to work with.

[bpaccaudjanspeedZ]

Hum turbo Janspeed here?

Hi all, the boost pressure is 5 psi for a carby set up, on this you can't put an intercooler because of fuel is also compress

But if this is a 280Zx set up, you could add an intercooler because only air is compress, don't know the pressure for this kit but this is a low pressure set up also

I am ok with MR G for the air fuel ratio gauge, and be carfull with overpressure...

[Mr.F]

You need to know the build data for your engine. The original kits fitted by Janspeed were designed to work safely with the unmodified original engines, so boost levels were very modest - 4 - psi at most.
However, many owners have later built lower compression engines using the early dished piston in the bottom end and adding the P90 "turbo" head. I have seen these run 0.5 bar safely. This requires modification of the original pop-off valve or replacement with an aftermarket adjustable version. It is unlikely that you could achieve and/or support the fuel and timing requirements of 1 bar boost with the original ECU, injectors etc.
The very last of the Janspeed turbos used a completely different system with a more sophisticated electronic control of the extra injector.

In essence, people will need more info / pictures of you version to be able to make informed comments and suggestions.

[glyn]

Thanks for the replies, i have only just bought the car so i can only assume the engine is stock, it runs the EFI not carbs. I took it out today after fitting the boost gauge and on tick over its about .6 vac and when i give it some welly it only goes up to about 0.2-0.3 bar which would be about the 4psi. It does have a micro dynamics EMS6 box.
Basically i just want to make sure everything is working as it should, i don't really want to modify the engine to take more boost because i just couldn't afford it, i was just expecting a bit of a kit up the arse when i put my foot down which it doesn't seem to have.
There is a slight whistle so i assume i must have a seal leaking slightly.
Is the pop off valve the same as a dump valve? and what would be the consequence of it leaking?
Plus Mr G how much would you want for the intercooler.
Sorry for all the questions and sorry if some of them are dumb but like i said i'm still trying to get my head around this turbo lark.

[Mr.G]

Glyn, this is what it looks like 240Z, 260Z, S30, , Aluminium Intercooler and radiator for Turbo system, janspeed etc.. - Z Club Classifieds

Not looking for a lot of money, just send me an offer via Private Messaging. If interested it can stay with my until you visit London.