ApexCars

I have an 87 951 that the PO did some mods to. He said it has Guru chips, MBC, 928 brake bias adapter and a purple cylinder just behind the air box marked "JET WORKS." Also, the brakes have the raised silver PORSCHE script on them. Does that mean they are turbo S brakes?

pikey7

Is the purple cylinder plumbed into the top intercooler pipe? I'm thinking it might be a modified Blow off valve.?

The script doesn't make the brakes the "turbo S". Check on the label behind the spare wheel for the option codes. You should see M030 for the sport package. Write em all down anyway, and check out what they are on the "general / option decoder" on the menu here.

ApexCars

No, it's not a blow off, I think it's some kind of boost enhancer. Also, I've checked the option codes and it does not have the sport package, however; the PO was turning it into a race car and he was not the original owner so many other things could have been done along the way. I had read somewhere that the regular 951 brakes had Porsche painted on them but the 951 S had the raised silver Porsche on them.

Scootin159

http://www.lindseyracing.com/Merchan...1BOOSTENHANCER Is that the purple cylinder? It's a popular mod & goes right where you're talking.

As for the brakes, all 951 brakes had raised lettering that says PORSCHE on it, the silver paint is probably aftermarket.

ApexCars

Yeah, I'm thinking it's something like that but a different model. I'd like to find out more about it.

yoyoguy2

i don't know what that is. it could be a check valve type boost controller i guess(re: boost enhancer), but i see no way to adjust it. also, if your car has a manual boost controller, the enhancer is redundant, so i don't know why you'd have it. i'm sure i should know this, but where does that line go from/to?

Sam Lin

It's an adjustable boost controller.

http://www.jazzmotorsports.com/shop/...e27c08bb96d021

Sam

pikey7

Maybe that IS the MBC the PO was talking about!? As yoyo says, though, where it is in the grand scheme of things would be better to know to be certain.

ApexCars

Sam - thanks for the link, I've been looking for that info. So this part is actually intended for a jet ski? Weird.

As for where its located - I'm not to familiar with turbo engines yet. I've only had the car a week, but I'm trying to learn. Anyway, there is a large rigid plastic pipe coming of of the left hand side of the IC with a port built into it just behind the airbox. J pipe maybe? Anyway the port has a fitting that connects to a flexible rubber line, then there is the jet works thing and then the line connects to a hard line that runs back under the manifold. The MBC is at the back of the engine bay and looks like this:

pikey7

sounds like the PO has the wierdest thing ever on there. From what I understand you saying on the jet-thingy, it is coupled into the main boost feed (from a Banjo fitting on the LH IC pipe)? If this Jet thing is adjustable, then it sould form something like the reliaboost or LR kit, and be an adjustable boot control. If it's a one way valve, then it's just plain wrong and I personally don't get it's point at all! It's also intersting to here it connects to the stock plumbing. This would probably mean it connects to the cycling valve, which is Porsches method of boost control. That makes two!

Then there's the "farmer Giles"(nice and rusty, yet brand new hose clamps. Interesting......) boost controller (if it is that ) behind the manifold. Can you explain to us where those pipes go to? If it is indeed a THIRD method of boost control, then its either a miracle you get any boost, or a miracle you're not running at 500PSI and blowing things up!

Have a check IF you still have the stock valve too. It's a cream/off white coloured disc, about 1-1/2" diameter and 1" thick under the manifold on the LHS of the engine, close to the firewall.

Olli Snellman

Raised (casted) Porsche text was used between 1985-1987. My 1988 have painted text. 951 S brakes can be found with painted and cast text. I have seen both.

ApexCars

I don't have the car with me at work today to figure where everything runs, but I can tell you that the engine bay is in nice shape. That isn't rust on the MBC, it's a brass valve. Also the car runs like a champ and is very fast. I had BJ at Istook look the car over before I bought it, (Don was out of town.) and he wasn't sure what the part was but he didn't think it was bad. He also said the car was fast and ran well.

pikey7

Fair enough. I personally woudn't trust 3 boost controllers as you don't know which one is doing the work, and what's being fed back to the brain, which tells it to change the fuel and timing settings........

ApexCars

Okay, I talked to Danno today and he pulled up the records on the PO. He said the JetWorks thing was an MBC, then when the PO upgraded to the later chips he was supposed to take it off and install the "farmer Giles" MBC which is apparently an early Reliaboost type controller that Guru was selling. So I pulled the JetWorks and plumbed in a new line there, but the CV is still hooked up. Should I disconect it? If so, how do you go about doing it? I understand I can just by-pass it for the boost line straight to the MBC but what about the other lines coming off it, what do I do about those? I've tried searching for a write up on this but I get tons of posts saying delete it but I haven't found how to actually do it.

So Pikey7 you win the Kewpie doll because you had it spot on.

pikey7

He he! I'll PM you my adress

The MBC replaces the CV. have a search on reliaboost here on the 951 board, and you'll find a ton of info. Alternatively, PM danno.

You will probably need to reset it too, after all that other stuff in there, you'll probably have affected the boost.