Turbo + Catalytic Converter

Cyto · 12-04-2009, 03:05 PM

Okay, well, this might sound dumb, but my recently posted problem might have something to do with my catalytic converter being gutted. So, I ordered a magnaflow converter to replace it.

As far as I know Toyotas don't require back pressure, but as soon as I gutted that converter the turbo went all beserk and yeah. Does the turbo need the catalytic converter? or what?

TripleC · 12-04-2009, 04:29 PM

A lot of people dont have them but it is only required if you have to pass emissions.. If so you may need a high flow cat. Mine has one but it also needed to pass emissions where the cars last home was.
I am not sure if i will take mine out it seems to not have any issues. If i were you i would just take it out or put the gutted unit back in

MA70-3.0GT · 12-04-2009, 05:06 PM

Contrary to popular belief no 4-stroke engine "needs" back pressure, for reasons which I'm not going to bother going into lest I open a whole nasty can of worms...

Anyway, all I'm saying is that removing or gutting a cat should have no effect on your turbo's operation. For the benefit of people who haven't seen your other thread, what is the actual problem you're having? Lack of power?

If so (and I'm guessing you gutted the cat because it was damaged already?) the escaped material from inside the convertor may be blocking the exhaust further down, it usually gets trapped in the back box. Pulling the whole system off & cleaning it out is the solution to this (or ideally replacement).

Let us know what the actual problem is if not that & I'll have another stab at it.

TripleC · 12-04-2009, 05:17 PM

Quote:

Originally Posted by MA70-3.0GT

Contrary to popular belief no 4-stroke engine "needs" back pressure, for reasons which I'm not going to bother going into lest I open a whole nasty can of worms...

Anyway, all I'm saying is that removing or gutting a cat should have no effect on your turbo's operation. For the benefit of people who haven't seen your other thread, what is the actual problem you're having? Lack of power?

If so (and I'm guessing you gutted the cat because it was damaged already?) the escaped material from inside the convertor may be blocking the exhaust further down, it usually gets trapped in the back box. Pulling the whole system off & cleaning it out is the solution to this (or ideally replacement).

Let us know what the actual problem is if not that & I'll have another stab at it.

I agree

check the back Box and see if your missing converter pieces reside inside

MA70-3.0GT · 12-04-2009, 05:19 PM

Never mind, I found the thread & linked it now...

http://www.toyota-supra.info/forums/...o-problem.html

So from what you're saying the boost is going through the roof & then the motor cuts out until it drops off? (known as fuel cut, designed to save the engine in case of a stuck wastegate)

If so then yes, you could have a stuck 'gate but as you say it happened after you gutted the cat you may have damaged/dislodged the actuator pipe or rod whilst working on the exhaust. Look at the bottom of the compressor housing under the intake pipe fitting & you'll see a small diameter (1/2") hose going from the turbo outlet to the wastegate actuator, check this is not split (for what it's worth change it anyway) and is securely clipped on at both ends.

If it is OK then you can do a simple check to see if the actuator is working or not. Apply (using a bicycle pump or similar with a gauge) no more than about 10psi to the actuator. The rod should start to move at about 7psi. I can't stress enough NO MORE than 10psi by the way... (actually the tsrm says 11.4 but hey...)

OK, so if you've done this & the rod IS moving as it should then all I can think of is you may have bent the actuator rod while working on the 'zorst... Either way make sure you fit a good bit of hose to the actuator & clip it on securely & then see if it's cured before spending out on parts you may not need.

Damn I'm crap at describing how to do stuff, hopefully this helps & you can get sorted without spending out again...

cre · 12-04-2009, 08:18 PM

You explained it fine MA70. I thought we'd already gone over this in another thread.

Cyto, a missing cat will not cause any problems... a clogged one will! At this age it's not uncommon at all for a cat to be clogged.

Just an FYI for the benefit of the group - When a cat gets clogged it is usually due to certain chemicals building up and glazing on the catalyst (it's not really something you can clean off). However, it is always worth checking to see if a blockage is actually due to loose debris collecting in front of the catalyst... this can be cleaned out by back flushing the cat with pressurized air (do not spray the catalyst directly with a high pressure blower though, the honeycomb is fragile).

Backpressure is garbage... BUT too large of an exhaust DOES have negative effects on N/A engines and *some* forced induction systems. I'm not going to go into it. The temperature bump exhaust gasses see while passing through a cat make up for what restriction is presented by a *decently flowing* cat. There is no reason not to run a cat other than just being a cheap SOB... if you're concerned about pressure get a high flow cat; it's less headache come emission time and less polution (if you're on of those wackos who doesn't believe humans can create enough polution to cause ecological problems try driving through any major city on a day with low barometric pressure.... F#$%ing idiots...).

Cyto · 12-04-2009, 10:52 PM

I ordered a cheapo Cat, and I've heard from 2 people that the wastegate is stuck. What do I need to buy? Any links of the EXACT part?
And thank you all for the support!

The car does already have a straight pipe out the back, but the Cat was destroyed during the overheating that caused the BHG.

Water got in the Cat and melted everything, he gutted the whole thing and put it back on there.

cre · 12-04-2009, 10:55 PM

You need to TEST the waste gate... don't just throw money at the car or you'll be broke in no time.

Cyto · 12-04-2009, 10:58 PM

Quote:

Originally Posted by cre

You need to TEST the waste gate... don't just throw money at the car or you'll be broke in no time.

We have, we took the little tube that connects to the actuator, put a ton of pressure and nothing happened.

2 different people suggested it was stuck shut.

I have been meaning to replace it for a few months now, but I havent known exactly which part I needed to replace.
Is this the right part?

http://www.ioffer.com/i/Toyota-CT26-...urbo-124287115

cre · 12-04-2009, 11:20 PM

Yeah, I was one of the people who suggested it... or was that someone else's post I responded to... doesn't matter anyway, just wanted to be sure you tested it.

That looks like the right part, but I would ask the the distance from the center of the two mounting holes from each other and the distance from the center of each hole to the center of the bell... just to be 100% sure.

If the gate itself is stuck a new actuator isn't going to help. You'll need to pull the turbo and see what needs cleaned up. You may want to disconnect the actuator's arm and then try moving the waste gate's armature by hand or with pliers. If the waste gate itself is stuck it is possible te actuator is also damaged now as well, so re-test it when it's disconnected.

12-04-2009, 03:05 PM	#1
Cyto 3" Exhaust Join Date: Jul 2009 Location: USA Posts: 103	Turbo + Catalytic Converter Okay, well, this might sound dumb, but my recently posted problem might have something to do with my catalytic converter being gutted. So, I ordered a magnaflow converter to replace it. As far as I know Toyotas don't require back pressure, but as soon as I gutted that converter the turbo went all beserk and yeah. Does the turbo need the catalytic converter? or what? __________________ Proud owner of a 1988 Toyota Supra Turbo, 105k Miles, and great condition. I might have to sell it to help pay for school so here's the link. http://www.toyota-supra.info/forums/...html#post72357

12-04-2009, 05:06 PM	#3
MA70-3.0GT 12psi boost Join Date: Oct 2009 Location: Crewe, England Posts: 356	Contrary to popular belief no 4-stroke engine "needs" back pressure, for reasons which I'm not going to bother going into lest I open a whole nasty can of worms... Anyway, all I'm saying is that removing or gutting a cat should have no effect on your turbo's operation. For the benefit of people who haven't seen your other thread, what is the actual problem you're having? Lack of power? If so (and I'm guessing you gutted the cat because it was damaged already?) the escaped material from inside the convertor may be blocking the exhaust further down, it usually gets trapped in the back box. Pulling the whole system off & cleaning it out is the solution to this (or ideally replacement). Let us know what the actual problem is if not that & I'll have another stab at it. __________________ '89 MA70 Supra GT aero 3.0turbo JDM, Rebuilt motor, K&N intake, 3" stainless turbo-back. New turbo and braided line kit... '89 Honda NC27 400, NC23 cams, open pipe, PC36a shock & possibly Showa USD forks... '83 Yamaha 29R XJ750E-II, number 69 off the line, only runner in the country? Original except Koni shocks '95 Honda PC26 CB500R, Winter hack, hateful, trying to sell it I'm not paranoid, they really ARE after me!!!

12-04-2009, 05:19 PM	#5
MA70-3.0GT 12psi boost Join Date: Oct 2009 Location: Crewe, England Posts: 356	Never mind, I found the thread & linked it now... http://www.toyota-supra.info/forums/...o-problem.html So from what you're saying the boost is going through the roof & then the motor cuts out until it drops off? (known as fuel cut, designed to save the engine in case of a stuck wastegate) If so then yes, you could have a stuck 'gate but as you say it happened after you gutted the cat you may have damaged/dislodged the actuator pipe or rod whilst working on the exhaust. Look at the bottom of the compressor housing under the intake pipe fitting & you'll see a small diameter (1/2") hose going from the turbo outlet to the wastegate actuator, check this is not split (for what it's worth change it anyway) and is securely clipped on at both ends. If it is OK then you can do a simple check to see if the actuator is working or not. Apply (using a bicycle pump or similar with a gauge) no more than about 10psi to the actuator. The rod should start to move at about 7psi. I can't stress enough NO MORE than 10psi by the way... (actually the tsrm says 11.4 but hey...) OK, so if you've done this & the rod IS moving as it should then all I can think of is you may have bent the actuator rod while working on the 'zorst... Either way make sure you fit a good bit of hose to the actuator & clip it on securely & then see if it's cured before spending out on parts you may not need. Damn I'm crap at describing how to do stuff, hopefully this helps & you can get sorted without spending out again... __________________ '89 MA70 Supra GT aero 3.0turbo JDM, Rebuilt motor, K&N intake, 3" stainless turbo-back. New turbo and braided line kit... '89 Honda NC27 400, NC23 cams, open pipe, PC36a shock & possibly Showa USD forks... '83 Yamaha 29R XJ750E-II, number 69 off the line, only runner in the country? Original except Koni shocks '95 Honda PC26 CB500R, Winter hack, hateful, trying to sell it I'm not paranoid, they really ARE after me!!! Last edited by MA70-3.0GT; 12-04-2009 at 05:23 PM.

12-04-2009, 10:52 PM	#7
Cyto 3" Exhaust Join Date: Jul 2009 Location: USA Posts: 103	I ordered a cheapo Cat, and I've heard from 2 people that the wastegate is stuck. What do I need to buy? Any links of the EXACT part? And thank you all for the support! The car does already have a straight pipe out the back, but the Cat was destroyed during the overheating that caused the BHG. Water got in the Cat and melted everything, he gutted the whole thing and put it back on there. __________________ Proud owner of a 1988 Toyota Supra Turbo, 105k Miles, and great condition. I might have to sell it to help pay for school so here's the link. http://www.toyota-supra.info/forums/...html#post72357

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12-04-2009, 04:29 PM	#2
TripleC 3" Exhaust Join Date: Nov 2009 Location: Fort Collins, CO Posts: 103	A lot of people dont have them but it is only required if you have to pass emissions.. If so you may need a high flow cat. Mine has one but it also needed to pass emissions where the cars last home was. I am not sure if i will take mine out it seems to not have any issues. If i were you i would just take it out or put the gutted unit back in

12-04-2009, 08:18 PM	#6
cre Toyota Racing Development Join Date: Apr 2007 Posts: 5,038	You explained it fine MA70. I thought we'd already gone over this in another thread. Cyto, a missing cat will not cause any problems... a clogged one will! At this age it's not uncommon at all for a cat to be clogged. Just an FYI for the benefit of the group - When a cat gets clogged it is usually due to certain chemicals building up and glazing on the catalyst (it's not really something you can clean off). However, it is always worth checking to see if a blockage is actually due to loose debris collecting in front of the catalyst... this can be cleaned out by back flushing the cat with pressurized air (do not spray the catalyst directly with a high pressure blower though, the honeycomb is fragile). Backpressure is garbage... BUT too large of an exhaust DOES have negative effects on N/A engines and some forced induction systems. I'm not going to go into it. The temperature bump exhaust gasses see while passing through a cat make up for what restriction is presented by a decently flowing cat. There is no reason not to run a cat other than just being a cheap SOB... if you're concerned about pressure get a high flow cat; it's less headache come emission time and less polution (if you're on of those wackos who doesn't believe humans can create enough polution to cause ecological problems try driving through any major city on a day with low barometric pressure.... F#$%ing idiots...).

12-04-2009, 10:55 PM	#8
cre Toyota Racing Development Join Date: Apr 2007 Posts: 5,038	You need to TEST the waste gate... don't just throw money at the car or you'll be broke in no time.

12-04-2009, 11:20 PM	#10
cre Toyota Racing Development Join Date: Apr 2007 Posts: 5,038	Yeah, I was one of the people who suggested it... or was that someone else's post I responded to... doesn't matter anyway, just wanted to be sure you tested it. That looks like the right part, but I would ask the the distance from the center of the two mounting holes from each other and the distance from the center of each hole to the center of the bell... just to be 100% sure. If the gate itself is stuck a new actuator isn't going to help. You'll need to pull the turbo and see what needs cleaned up. You may want to disconnect the actuator's arm and then try moving the waste gate's armature by hand or with pliers. If the waste gate itself is stuck it is possible te actuator is also damaged now as well, so re-test it when it's disconnected.