Montego

iTrader: (1)

lol... I have the money. I just don't want this to be a regular occurence.

CantGoStraight

About the only way you can pevent overboost is with a mechanical popoff valve that will dump enough air to maintain your max boost level, of course even these can fail so there just really isn't a fix for failure. I can see the lure for the LS-1 easy 400rwhp with minmal effort good gas milage with the 6 speed. N/A so no boost issues to worry with.

Monsterbox

iTrader: (6)

where do you purchase a "pop off valve" that will release all boost to atmosphere if exceeded by value

dgeesaman

iTrader: (7)

You mean other than the apex seals?

Montego

iTrader: (1)

I mean early death by crazy boost.

Edit- I just thought of something: People bag on the Apex'i BOV and how it does not hold boost. If found this not to be the case.

adam c

iTrader: (2)

It appears that cold temps have nothing to do with this, and it isn't that cold in San Diego!!!!

alexdimen

iTrader: (13)

Montego, do you have a boost gauge? If so, how quickly did the boost get out of control after there was a malfunction? I'm really sorry to hear of your bad luck, but I'm trying to learn from it.

+1 I'm interested in this as well.

Rotary4tw

iTrader: (3)

It's really unfortunate what happened to Montego. I just wanted to clear up a few things, and if I'm wrong, I want them corrected by the longtime forum members, so others don't repeat the same mistakes.

1) Overboost from a wastegate failure can can be prevented.



Every wastegate setup I have seen on the 3rd gen has some sort of vaccum line(s) running to it. These lines are often within a few inches of the turbo, downpipe, manifold. If these lines are compromised, the wastegate is compromised, creating overboost if you hammer on the gas.

When I first saw my downpipe and manifold glowing magma hot red on the dyno with Steve, I knew there was way too much heat for anything important to be near that area.



I have seen lots of people mount their MBC's and EBC's right under the stock ABS sheild, or very near it. This is probably unwise, considering if the solenoid goes (melts), your wastegate is also compromised.

Conclusion. Don't mount EBC or MBC near the hot turbo area. If you do, make sure it is sheilded properly, with very high temp hose guards or some other solution.

But what if despite your best efforts, something melts, the wastegate just fails internally, or you are "mechanically challenged" (like myself most of the time) and hook the system up wrong?

1) As Rynberg said, if you are using a PFC, set the fuel cut to be a few pounds under what you are running. You probably don't want anything over 16.5 psi if you normally have pump gas in the car. The lower the better... Somebody can chime in the specifics on where the setting is, but I know it's fairly easy to do yourself.

2) When you have your car tuned, set the car up with a crazy fuel dump as you pass your desired boost. This will choke the car out with too much gas, and your chances of engine failure should choke out with it. I'm not sure if 1) and 2) are redundant, but both seem to be accomplishing the same thing, one is just automaticly, and one is hardwired into your map.

3) Install a pop off valve. They cost about $125 bucks, and will prevent you from overboosting. They do not fail, it's a simple mechancial valve that opens your intake at the desired pressure. Set it for 2-3 pounds over your limit, and as above, under 16.5 on pump gas to be safe.
I ordered mine from Jason @ Rx7store.net $125 seems like a good insurance policy to me!

Also, for a wide assortment of high temp protective material (which IMO you should line everything important near the "magma zone" with this stuff) check out Speedzone.

4) If there are more options, please chime in!!!



In conclusion...

OVERBOOST can be prevented. Not only can it be prevented... you are foolish if you don't take some measure to prevent it. Every local Rx-7 owner I know has overboosted over 20psi at one point, for various reasons. (4 for 4 100% being hooking up their boost controllers backwards, but I won't use any names!)

Good luck, hopefully no more engines see 24psi on pump gas... unless they are running a Howard Colemanesque Auxillary Injection system and making stupid crazy rwhp. (For more info check out that A.I. subforum, lol)

-R4tw

RX7 RAGE

iTrader: (22)

good info rotary4tw, i might have to invest in a pop off valve myself.

dgeesaman

iTrader: (7)

I agree - I would never put a boost controller near the hot zone.

Also, check on the boost controller hoses. On stock turbos, there is no reason for the wastegate hose to be near the hot zone. You just have to do your best to ensure it's airtight and secure.

The popoff is not a bad idea, and yes it is very reliable.

Dave

mdpalmer

iTrader: (24)

Elliot!!!! Noooooooo!

Man I'm so bummed to hear of your misfortune. Keep us updated on what you find out about the nature of the failure (wastegate line coming undone, etc.). I know you've had a strong motor for a good while thanks to Steve and R&R.

FWIW, this could have happened to ANY turbocharged engine, not just a rotary! Good luck and let us know what happens, we'll keep our fingers crossed for you!

dubulup

no that's not the only way...about the easiest way has already been stated...a properly operating FUEL CUT!!
which will scare the **** out of you...but stop boost from rising. I've seen this personally many times to the XX.1psi

Montego

iTrader: (1)

found the culprit:

It was the hose that controls the wastegate. It popped off right at the turbo, the zip tie was missing and the nipple had oil all over it. Most likely the oil came from leaky turbos since other than the nipple, the turbos are free from oil. bummer.

Since this is totally preventable (pop off valve for safety) rotary is staying.

there ya have it.

RotaryEvolution

iTrader: (30)

sucks to hear, i personally try to keep the original spring clamps as much as possible for that reason. zip ties are just unreliable but they do work.

Maximum

iTrader: (5)

Too bad about that wastegate line but good to hear you're sticking with the rotary. I realized there was no way you'd creep 13 psi about 30 seconds after I posted the comment about the wategate porting. Good luck with the rebuild!

RX7UP

Sorry about the loss...

Good to hear about your "reliable" come back!...

Enjoy every stage of it... It's like moving, you get a chance to through out what you don't need.

Dwayne

Rotary4tw

iTrader: (3)

Right before winter this year, we had a local guy named Bruce fire up his new single turbo setup for the first time. He hit about 7psi and then lost all power in the car.

I came over and listended to it, and it sounded blown. Couldn't idle, chugged, huge vacuum jumps...

Then we found out he simply blew off some hoses on his manifold (Thanks GooRoo), which caused it to run really poorly. I felt like a total idiot because I was sure it was blown from seeing it in person.

Do a compression test. If you don't have a compression tester, pull the plugs and turn the car over and just listen for the pulses.

It may not be blown!

-R4tw

RotaryEvolution

iTrader: (30)

to be honest... and after having been through this, he is right for thinking the engine is toast. anything over 18PSI on pump fuel(even with the appropriate fuel upgrades) you can pretty much consider a goner.

njstreetrx7

i always hated the stock twins SO MANY PROBLEMS

Sobr609

iTrader: (2)

atleast it wasn the motor, keepin fingers crossed

rynberg

This problem has NOTHING to do with the stock twins and could have occured with any turbo setup on any car.

alexdimen

iTrader: (13)

Where do you install one of these and how do you adapt it to the stock intake system?

njstreetrx7

im just talkin in general not this current issue

GoodfellaFD3S

iTrader: (213)

Thank God for water injection . I recently saw 23 psi on pump fuel with my 500R because I didn't change my dipswitch settings (of all things) hidden on the back of my profec B. The setting for internal wg is different than the setting for external wg, and I found out the hard way. Motor took it like a champ, so I can joke about it now, lesson learned

Montego

iTrader: (1)

sorry I missed this post.

I got three . one on the pillar, the boost controller, and the PFC. But I don't monitor everytime I WOT. I look at them all the time. Just not this time

This is the way it happened:

Intake temps 18C, WOT on third gear at around 3500 RPMs. Car responded well, as expected it was cold outside. Then I'd say around 5-6K the car got darn fast for a couple of seconds no more. Before I got my foot off the gas nor realized that it was "too fast" the car fell flat on it's face. I don't think I remember seeing my boost controller flashing red maybe it did. It all happened too fast.

The only way I would had a chance IMO is if I would had been looking at my gauge at the time.