T78 Rebuild-Update
10-09-02, 05:01 PM
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T78 Rebuild-Update
The turbo was shipped to Majestic Turbo in Waco, Texas to be fixed. If you saw a previous post, it had a damaged turbine.
The turbine can actually be repaired and is being done currently. Additionally, the turbo was in need of a general rebuild, new bearings, etc...
On top of that, for very little additional money, they can upgrade the compressor side. What they recommended was a T64 wheel of Garrett design (I believe), not Turbonetics.
One of the gentlemen there, Kevin I believe, mentioned that the GReddy T78 was almost identical to his T66 which is used on a drag bike. I'm not sure if he meant compressor diameter or what. If so, then going to a T64 wheel wouldn't be that great of a change. They did say this wheel can support 700hp. It has two additional blades and can flow more cfm per pound of boost than the stock GReddy wheel.
All told, the bill is going to be about $815. Not cheap, but much less expensive than a new T78 at $2500. It should flow much better than the T78 and provide better street manners to boot. I think Gordon's turbo us upgraded similarly but I do not have the specs on his upgrade.
Any thought/opinions on the compressor upgrade appreciated.
Michel
The turbine can actually be repaired and is being done currently. Additionally, the turbo was in need of a general rebuild, new bearings, etc...
On top of that, for very little additional money, they can upgrade the compressor side. What they recommended was a T64 wheel of Garrett design (I believe), not Turbonetics.
One of the gentlemen there, Kevin I believe, mentioned that the GReddy T78 was almost identical to his T66 which is used on a drag bike. I'm not sure if he meant compressor diameter or what. If so, then going to a T64 wheel wouldn't be that great of a change. They did say this wheel can support 700hp. It has two additional blades and can flow more cfm per pound of boost than the stock GReddy wheel.
All told, the bill is going to be about $815. Not cheap, but much less expensive than a new T78 at $2500. It should flow much better than the T78 and provide better street manners to boot. I think Gordon's turbo us upgraded similarly but I do not have the specs on his upgrade.
Any thought/opinions on the compressor upgrade appreciated.
Michel
10-09-02, 05:05 PM
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https://www.rx7club.com/forum/showth...hreadid=120275
That's the link to the original thread with pictures of the damaged turbine.
I'd also like to thank Gordon for pointing me in the right direction :-)
Michel
That's the link to the original thread with pictures of the damaged turbine.
I'd also like to thank Gordon for pointing me in the right direction :-)
Michel
10-10-02, 01:46 AM
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LOL, they made YOU sad...I think it ruined my entire month :-) I just hope I'm making the right choice in terms of compressor and I don't receive a dud.
Michel
Michel
10-18-02, 03:40 PM
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The turbo is on it's way back from Majestic. I just paid for the "damages" which totalled $819. Apparently a Garrett wheel was swapped in. Features more blades. They wouldn't tell me the compressor size nor provide any sort of compressor map. One guy previously mentioned a T64 but he didn't sound too confident. The senior guy (Kenny?) just said it was in fact a Garrett GT series and that they didn't share specs. He did slip and say "79". Not sure. End result, he said, was that I'd be very pleased. It flows more cfm at the same boost levels than a standard T78 and will spool up more quickly.
The $819 included a complete rebuild, the fixing of the turbine blades plus the machining of the compressor housing for the new wheel, and of course the cost of the new wheel. Rebuild alone ran about $650. We'll see how she works! I'll take a few pics when I get it back next week.
Michel
The $819 included a complete rebuild, the fixing of the turbine blades plus the machining of the compressor housing for the new wheel, and of course the cost of the new wheel. Rebuild alone ran about $650. We'll see how she works! I'll take a few pics when I get it back next week.
Michel
10-18-02, 06:52 PM
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majestic won't tell you about the compressor, because they themselves don't know. they don't have compressor maps, because garrett doesn't provide them. in fact the companies that do provided them, like turbonetics, purposely give the wrong numbers. the turbo industry regards compressor maps as proprietary information and they do all they can to hide their actual numbers.
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10-18-02, 08:32 PM
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Yeah I'm not complaining too much...still...I would have preferred to put that money towards a large oil cooler kit and a new differential...or 850 primaries, or a rear wing, or a roll cage...:-)
Thing is, none of the replacement parts are from GReddy. They're sourced elsewhere because they can't seem to get the parts in a reasonable amount of time. Word from GReddy's mouth is that if it goes bad, you're supposed to throw it away and give them $2500 for a new one. Nice marketing strategy.
Yes the words proprietary was mentioned by Majestic. It's nice to know what you're getting however.
Michel
Thing is, none of the replacement parts are from GReddy. They're sourced elsewhere because they can't seem to get the parts in a reasonable amount of time. Word from GReddy's mouth is that if it goes bad, you're supposed to throw it away and give them $2500 for a new one. Nice marketing strategy.
Yes the words proprietary was mentioned by Majestic. It's nice to know what you're getting however.
Michel
10-18-02, 09:48 PM
#10
Originally posted by rx7tt95
Yeah I'm not complaining too much...still...I would have preferred to put that money towards a large oil cooler kit and a new differential...or 850 primaries, or a rear wing, or a roll cage...:-)
Thing is, none of the replacement parts are from GReddy. They're sourced elsewhere because they can't seem to get the parts in a reasonable amount of time. Word from GReddy's mouth is that if it goes bad, you're supposed to throw it away and give them $2500 for a new one. Nice marketing strategy.
Yes the words proprietary was mentioned by Majestic. It's nice to know what you're getting however.
Michel
Yeah I'm not complaining too much...still...I would have preferred to put that money towards a large oil cooler kit and a new differential...or 850 primaries, or a rear wing, or a roll cage...:-)
Thing is, none of the replacement parts are from GReddy. They're sourced elsewhere because they can't seem to get the parts in a reasonable amount of time. Word from GReddy's mouth is that if it goes bad, you're supposed to throw it away and give them $2500 for a new one. Nice marketing strategy.
Yes the words proprietary was mentioned by Majestic. It's nice to know what you're getting however.
Michel
10-18-02, 11:13 PM
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The rebuild actually ran more than $100 less than your rebuild Ernie...the rest was fitting the new compressor :-) Out of the $650 for rebuild, the turbine cost about $150 to be fixed. So figure $500 for a basic rebuild.
10-20-02, 04:44 PM
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Originally posted by rx7tt95
Yes the words proprietary was mentioned by Majestic. It's nice to know what you're getting however.
Michel
Yes the words proprietary was mentioned by Majestic. It's nice to know what you're getting however.
Michel
10-24-02, 04:45 PM
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Turbo arrived today. Visually, you can't tell the turbine was ever damaged. Very nice. The compressor was machined out (you can visually see the machine marks) and, according to the receipt, a GT79 wheel was installed, whatever that is.
I've never taken the compressor housing off a turbine before. Seems simple however and I'd like to measure the diameter of the compressor wheel just for kicks. I'll post pictures when I get back from work. Everything looks really good though...they coated the center section (no more rust) and there's absolutely no play in the shaft. Spins quite easily too. She goes on the car Saturday.
Michel
I've never taken the compressor housing off a turbine before. Seems simple however and I'd like to measure the diameter of the compressor wheel just for kicks. I'll post pictures when I get back from work. Everything looks really good though...they coated the center section (no more rust) and there's absolutely no play in the shaft. Spins quite easily too. She goes on the car Saturday.
Michel
10-24-02, 10:53 PM
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Here's the entire unit sans front and rear housings. Oh, and thanks Gordon for the head's up regarding Majestic and their work with the T78. I should be hitting the dyno within three weeks or so.
Michel
Michel
10-26-02, 08:59 AM
#22
That is a huge compressor wheel. Curious if Majestic bought a new turbine housing and machined it to fit your trimmed turbine, assuming they trimmed the turbine to remove the damage. If they did not custom fit the turbine housing I wonder what affect it will have on response. Straight out of the box I feel the T78 is one of the more responsive large singles sans BB.
10-26-02, 08:11 PM
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Michel, give me a call when you get your car all back together. Looks like I'm gonna be waiting atleast another month for mine to be done. I would love to feel the T78
Mike
Mike
10-27-02, 01:38 AM
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I actually didn't send the turbine housing to them, just the compressor housing, center section and of course the turbine/compressor wheels. I intended to have the turbine housing ceramic coated. This was put on hold due to the cost of rebuilding the turbo.
Essentially what they did was machine out the compressor housing. I can't really gauge how much material was taken out, but it's noticeable. Measurement was taken at the base of the compressor. I'm not sure if this is the correct way to measure it.
I got it installed today (Saturday) and just got home, sigh...started at 8am and finished about 1:30. There were numerous problems with the installation but it's together and running.
I have not tuned it so I was treading lightly on the way home hitting about .8kg/cm2. I have to work out all the bugs here first. Not sure if I have the wastegate hooked up to the boost controller correctly, etc...Just need to double check everything in daylight.
The car is definitely fast although it naturally doesn't build speed as easily as the stock twins. Once this monster spools, it's quite scary to be frank. The sound alone sends chills up your spine.
I added the Borla XR1 midpipe and it does an INCREDIBLE job of sound deadening. Car sounds great with the Borla and a GReddy Power Extreme.
Overall the engine seems to "breathe" much easier and general engine response off boost is improved without a doubt.
Tomorrow the wideband is going on and I'll be trouble shooting that and doing a bit of tuning. More feedback to come! Right now it's too early to tell if I'll like this setup. All I can say is that it's "interesting". A good afternoon of troubleshooting and tuning may of course change all that :-) Mike, if you want to swing by, feel free. I think Joe Castleberry is coming down with his T04s for a bit of tuning as well.
Michel
Essentially what they did was machine out the compressor housing. I can't really gauge how much material was taken out, but it's noticeable. Measurement was taken at the base of the compressor. I'm not sure if this is the correct way to measure it.
I got it installed today (Saturday) and just got home, sigh...started at 8am and finished about 1:30. There were numerous problems with the installation but it's together and running.
I have not tuned it so I was treading lightly on the way home hitting about .8kg/cm2. I have to work out all the bugs here first. Not sure if I have the wastegate hooked up to the boost controller correctly, etc...Just need to double check everything in daylight.
The car is definitely fast although it naturally doesn't build speed as easily as the stock twins. Once this monster spools, it's quite scary to be frank. The sound alone sends chills up your spine.
I added the Borla XR1 midpipe and it does an INCREDIBLE job of sound deadening. Car sounds great with the Borla and a GReddy Power Extreme.
Overall the engine seems to "breathe" much easier and general engine response off boost is improved without a doubt.
Tomorrow the wideband is going on and I'll be trouble shooting that and doing a bit of tuning. More feedback to come! Right now it's too early to tell if I'll like this setup. All I can say is that it's "interesting". A good afternoon of troubleshooting and tuning may of course change all that :-) Mike, if you want to swing by, feel free. I think Joe Castleberry is coming down with his T04s for a bit of tuning as well.
Michel
10-27-02, 11:20 PM
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Managed to get the wideband hooked up, still having problems setting up the map watch. The maps I am running, courtesey of a forum member, were very rich, designed that way, so it'll be a gradual leaning out process to get the car up to speed. I leaned out everything up to 7kg/cm2 tonight. The WB is showing 10.5 and below above that and it stutters if I'm on full throttle. Needs a bit more tuning :-) She's starting to pull nicely however and the speed is very deceiving. Very smooth. The sequentials were more rabid in many ways. Anyway, here's a pic. Work's a bitch right now so it'll be a slow process getting her up to speed.
Michel
Michel