the truth about 3.2 turbo conversions

[WydRyd]

Nope, my OEM FPR was removed and I guess my ex-mechanic added it to his spare parts collection Looked everywhere for it to no avail

Or do you think I'm better off going with the MR2035 that does it all in the one FMU and trashing the Proto FPR?

What size fittings are the stock lines? 1/4 NPT or 1/8?

Which model Autometer A/F gauge did you buy, with the telltale?

[greglepore]

Merv-I believe the stock fittings are metric, but any good hydraulic shop should be able to either put npt fittings on your hoses or make up custom hoses using the existing fittings, new hoses and new crimps.

Question for you guys-what does Proto charge for their rebuild kit? What symptoms does a fpr in need of rebuild exhibit? Mine seems to "stick" occasionally-ie. sometimes, usually the first time I make a hard run into boost, the boost comes up but the power is off, then "whoosh", while subsequent hits seem fine-not sure if something is sticking or not.

Merv, given the location of the Proto fpr and the pain it is to install, I'd give serious consideration to mounting a new one in a more easily accessible place. You'll need to have at least 3 custom hoses made to do that, but it'd be worth it, given that the hoses are likely in need of replacement as a preventive deal anyway.

[raceman]

Proto modifies the stock Porsche FPR to be a boost sensitve rising rate unit at a claimed 3.82-1 ratio. lf Merv`s needs a rebuild already...l think the whole idea is clever and a great way to make tons of money for Proto but consider the dangers here. l really can`t see this unit being even close in reliability and build quality the the BEGI unit.This is Corky Bell we`re talking about here amigos.His FMU`s are the best available and are proven to do what`s needed of them,and more.The quality,reliability,ADJUSTABILITY,and warranty plus dependable tech support.Call BEGI,talk to Corky yourself like l did,several times.l`ll say it again though Merv,get the guages.Tuning took me three hours blasting through the gears on a remote desert hiway with some hand tools and an apprentice along to watch the guages for me.There is no way l could take in the tach,boost,fuel pressure and A/F ratio when l was caning it.That`s where a more sophisticated data logging system would be helpful but l just didn`t want the extra bother.lf this was a twin turbo Supra l`d go with the Japanese space program system but for this car plain guages are fine.l`ll get the model #`s of what l`ve installed if you want to follow suit with an affordable and simple set up like mine.My cockpit looks pretty cool right now

[david.avery]

Greg, a thought for you: There is a recent thread around about the traces in the air flow meter, that are commuted by some "wipers". They wear out and cause bad part throttle response. There is a tech article about moving them to work on fresh substrate that improves the throttle response (on my list to do). This could be amplifying our issues, mine seems a bit "sticky" too...

[greglepore]

The Protomotive unit I have isn't a modified Porsche unit by any stretch-its probably one of the "copies" Corky mentions, but it is a large billet alu fpr, not at all like the stock unit. I think I still have a stock unit somewhere.

David-Yeah, I know about the wiper; mine likely needs a tune (actually I keep a spare afm, may just swap that) but this isn't that, I don't think. The afm issue is usually off idle or consistent flat spots, this is more like the first time you hit real boost in say, 2nd gear, the engine seems to bog a bit, the rate of boost rise falls off, then POW, its back to normal with no change in throttle position. Feels very much to me like the fuel pressure isn't going up, then wham, it does. Need to get a cockpit fp gauge, I have one on the rail but its not useful for anything other than idle.

Raceman, yeah, I'd like to know what you're using.

[WydRyd]

Originally posted by greglepore
The Protomotive unit I have isn't a modified Porsche unit by any stretch-its probably one of the "copies" Corky mentions, but it is a large billet alu fpr, not at all like the stock unit. I think I still have a stock unit somewhere.

David-Yeah, I know about the wiper; mine likely needs a tune (actually I keep a spare afm, may just swap that) but this isn't that, I don't think. The afm issue is usually off idle or consistent flat spots, this is more like the first time you hit real boost in say, 2nd gear, the engine seems to bog a bit, the rate of boost rise falls off, then POW, its back to normal with no change in throttle position. Feels very much to me like the fuel pressure isn't going up, then wham, it does. Need to get a cockpit fp gauge, I have one on the rail but its not useful for anything other than idle.

Raceman, yeah, I'd like to know what you're using.

Greg, I agree, the Proto FPR is a custom aluminium unit. It's huge! It's not a crimped OEM FPR.

Todd replied to my query and he said to remove the FPR, pull the top off and check that the diaphragm isn't stuck or torn and to also check that the piston moves up and down freely. If not, it may just need to be removed, cleaned and lubed.

The diapgragm is made of Viton material, about 0.060" thick. It's simply cut to size for their custom regulator.

Under NA driving conditions, it operates at 1:1 with a base pressure of 2.8bar (40psi). Under boost, the check-valve closes off and runs a 3.8:1 ratio with a base pressure of 2.8bar.

My fuel pressure gauge on the rail is showing me an idle pressure of 43psi!!! And I can also hear buzzing from what I think is the FPR under load. This typically means the diaphragm is torn.

Wouldn't surprise me, since the diaphragm in the fuel damper was torn too a short while back and pissing fuel into the vacuum port and flooding the engine Something's seriously gone wrong with the FPR I suspect

EDIT: Raceman, post some pics of your cockpit

[raceman]

l`ll get some cockpit pics on here one day.My info about the modded Porsche FMU comes from T.knighton.According to him they take the stock Porsche unit and mod it to be rising rate.This procedure involves somewhat of a transformation,not just crimping the thing to raise the base pressure.lf the units you guys refer to mounts in the stock location then most likely at it`s core is a factory part or not,l`d have to see it to know.

[Peppy57]

raceman: Thanks for all the help on the door sills you sold me
amigo