BigJim

So i went to the drag strip today.

4th run, 1/8 mile mark aprox one of my intercooler couplers blows. @ndary turbo overspools and starts whining.

So i fix the coupler so i can make it home but if i get near 4500 rpm with to much throttle all i hear is whining. It sucks

Then, for some reason, reverse wont go in at all. It feels like a bar is locking me out.

Yea if anyone has ideas let me know.

BigJim

any chance it is rebuildable? Not that these turbos only have 12000 miles on. Previous owner had them replaced by the Mazda Dealership shortly before i bought the car.

BoostedTimmy

I highly doubt your turbos are shot from blowing a coupler!

You probably blew a vacuum hose, luckily you can get to most/all of the turbo oriented ones without even removing the uim. Try and find one of the twins troubleshooting guides here on the forums.

I have no idea why you cant shift into reverse...

BigJim

pretty sure my 5th gear synchro went. But as for turbo, would a vac leak cause it to whine like that? never heard that before so i dont know.

BoostedTimmy

Yeah it will cause all kinds of wierd ****

What happens when you get on it? Does the primary hold and the secondary just never come on or makes noise?

BigJim

to afraid to really get on it. primary boosted fine. Then around the time the secondary starts to spool, vacuum nearing 0 i hear this fairly loud whine so i let off.

BigJim

anything specific i should look for in terms of the cause of the whine. ps it sounds like a high pitched vacuum when it starts to spool.

dgeesaman

iTrader: (7)

Remove the front and rear inlet pipes to the turbo and see how much shaft play is there. If it's rubbing the housing then the turbos are definitely shot.

But I think you still should look for a boost leak of some kind.

Dave

BigJim

any ideas on where to start for a leak? how can i go about pressure testing the system?

4CN A1R

iTrader: (6)

maybe you should just check all yer hoses for a leak or a break? did you ever get the hoses replaced with silicone ones? they tend to harden and crack when under heat for long periods of time...

but with the milage you have on the car, i dont think it would be nessesary yet. maybe it was ran hard many times and due to constant heat, this sped up the process? could you supply more info?

BigJim

Yea Heres my Details on the car

1993 Rx-7 Touring
~21k on KDR Rebuild with Streetport
~11k on new turbos from mazda dealership
Apexi Power FC (dynotuned at 310 rwhp)
Mazdaspeed radiator
Mazdaspeed short shifter
Silicone vacuum hoses
M2 Intake
Greddy elbow, all hard pipes to Peter Farrel Supercars SMIC
Bonez downpipe
High flow cat
Custom catback exhaust
Supra TT fuel pump

All the hoses i can see are silicone. I looked around the turbo solenoids and and everything is still connected so now to start trying to find cracks. Can someone explain why a vac leak would cause it to whine though? If i understand how it would cause the whine i will know more precisely where i should be looking

as for being run hard, not so much. The previous owner only drove it 2k miles in 2 years. That was just around chicago. As for me, i usually stay out of boost because gas is to damn expensive. If i did run it hard it was only for short periods of time and few and far between.

thanks in advance guys.

4CN A1R

iTrader: (6)

there are propane and dye tests that i know of...but a friend of mine sugested using a spay bottle with a little bit of soap mixed in. spraying down all the hoses and then turning on the car...it should bubble where the leak is. only problem with this is, its very hard to spray around all the hoses.

4CN A1R

iTrader: (6)

dave from kdr told me that the hoses by the turbo housing, even being silicone and heat resistant, will still harden and crack. you most likely have a blown or cracked hose down there with a restrictor pill that is not getting air to it.

my best guess dude...

wReX

iTrader: (6)

http://www.autosportracetech.com/RX-...leshooting.htm

...or just go non-seq, hah

BigJim

so i removed the intake from the turbo closest to the front of my car which i understand to be the secondary. Please tell me im right in believing that. Well i noticed some oil near the impeller but no shaft play and everything looked fine. How do i go about getting to the exhaust side?

BigJim

yup, im retarded, that front one is the primary. Well i took the 2ndary intake off and there was some oil. And then i grabbed the shaft and went at it. In and out just a little bit. Up and down, enough to make a click click noise as i pushed it each direction. Such a fresh rebuild on them and already dead. What sucks is, im really broke right now so i have 3 options. Put it up till i can afford to fix it(income taxes), sell it, or have you all chip in to buy me the rebuild kit for the turbo. And since the latter probably isnt much of an option, if it is let me know though, it sounds like ill be selling it. Cant afford to keep full coverage on it and have a 2nd insurance to pay for.

BigJim

today is a sad sad day.

gainer_reniag

You can mess up your turbos from having a boost leak? I shot one of my intercooler couplings off the other day because some ******* didnt put it back on right.... ahem the next day i boosted a little bit to pass someone. went up to about 6 psi and heard a noise that kind of sounded like a cobra superchager. i also have a exhaust leak somewhere i need to get fixed. but today i went WOT and it pulled like a champ and i didnt hear the noise so hmmmmmmmmmmmmmm.

BigJim

this is what happened in my mind...

Going at 12 psi in 2nd gear. Turbo is spooled, intercooler and everything is pressurized. This pressure is keeping the turbo at x rpm. The intercooler piping goes and theres no longer pressure after the turbo. This lack of pressure allows the turbo to go from x rpm to x+ way to much rpm and burn out the bearing. If anythign thinks this isnt possible let me know. Lotsa play and oil that wasnt there the other day though

dgeesaman

iTrader: (7)

Two points:

Yes, a boost leak can overrev the turbos and damage them.

Also, rebuilt turbos typically don't have the success rate that new or good lightly used turbos do. Something about the design of the bearings that makes replacing them a dicey proposition, plus the fact you have to have *two* perfect rebuilds working together. So if you think about it, if the bearing install fails 25% of the time then rebuilding the set will not be successful 75% of the time.

dontlift

Your description is accurate, but I've always thought it would just add to the wear on the turbo rather than a sudden failure. Just about every FD out there has probably had it happen without blowing a turbo.

Rather than a rebuild kit, I'd suggest picking up a good used set of twins.

s-thetikz

iTrader: (1)

used twins don't go for more than 400 (ive seen them go for 200-300)- pick up a decent set and install it yourself.

BigJim

so im looking at like a grand to get it on the road again. 400 for turbos and 600 for transmission. this sucks. by the time i get that all done itl be winter. maybe ill get the trans now and save up for single turbo. maybe try and trade my first gen -se for a turbo kit.

dgeesaman

iTrader: (7)

Your 5th synchro is probably brokena nd the pieces are blocking reverse.

If you DIY it's not a $600 job at all.

Dave

recon fd

Man you already put it up for sale?