RECollecter

iTrader: (11)

Hey has anybody rebuilt there HT-12 assy. If so, what is the level of difficulty? and Where is the cheapest place to get parts such as rebuild kit, compressor upgrade.

Mahjik

iTrader: (1)

Good luck. That's the problem which is finding the kit to it. Bryan at BNR stopped rebuilding them because of the difficulty in finding parts. Turbo City used to carry them, but they stopped a few years ago.

Try this thread and see if some of the info is still valid:

https://www.rx7club.com/3rd-generation-specific-1993-2002-16/stock-sequantial-turbocharger-rebuilder-612254/

IRPerformance

iTrader: (41)

Don't bother. The rebuilds always fail. Go with a set of BNRs, 99 twins, or a known good set of stock whens if youre on a tight budget.

Andrew

iTrader: (1)

This seems to be the prevailing opinion here, but I haven't seen anybody back it up. I'm not trying to call anybody out, but I want to know what people's experience has been. Are most of the failures a result of DIY, or a bad shop, or perhaps poor parts?

I have the engine in my FD out for a rebuild and need to do something with the turbos. G-Pop Shop is not too far away, so I could get a rebuild there but I don't want to base my decision on everyone's opinion unless it's based on real experience.

katit

iTrader: (1)

My rebuild failed. Shaft broke. Not sure if it was due to rebuild

dgeesaman

iTrader: (7)

The best "prevailing opinion" to listen to is probably Bryan @ BNR or someone else who's rebuilt many FD turbos. His opinion is that rebuilding the stockers usually doesn't work. Keep in mind that the distortion he mentions is due to the fact that FDs create such insanely high EGTs.

https://www.rx7club.com/showthread.p...ld#post7563768
https://www.rx7club.com/showthread.p...hlight=rebuild

TpCpLaYa

iTrader: (10)

sounds about right /\

theorie

iTrader: (31)

if you want to keep the stock twins, just buy a used working set off another forum member.

i am currently using the stock twins, but i combined the front CHRA from one set and the rear CHRA from the other set. i also ported the wastegate + the manifold before putting the whole assembly back together. works great for me

baggedoutmazda

look in the f/s sale section, there is a few sets of low milage twins for sale cheap. i picked up a used set cheap just so i had spares for when mine fail.

Mahjik

iTrader: (1)

From what I've observed over the years, the people who had their turbos balanced after the rebuild had a much higher percentage of success than those that didn't. The problem is, the majority of people who did their own rebuilds never rebalanced the turbos which is most likely why there was a such a high ratio of early failures.

I think the other side of it was shady shop work. Some of the shops, you never knew if they balanced the turbos or not (most likely most of them didn't).

dgeesaman

iTrader: (7)

While that's no doubt a factor, when you consider that guys like Bryan are unwilling to rebuild them there is more to it than missed balancing.

Dave

Mahjik

iTrader: (1)

I've never seen Bryan mention anything other then the difficulty in getting the HT12 parts which is why he switched to the newer style BNR's (which was coincidentally when he stopped doing stock rebuilds).

smoke wagon

iTrader: (4)

I rebuilt my primary turbo. I haven’t had any problem with it so far, it boosts great. I went ahead and rebuilt the turbo because I had to remove the exhaust turbine for another one because an apex seal turned it into hamburger. The rebuild kit was $150 and if I can remember came from Turbo City or Turbonetics. I think Turbo City no longer carries the kit. The link I had to whomever I used to buy them from is not responding. While I was rebuilding it I sent the impeller along with the replacement turbine wheel off to Turbo City for balancing. I attached some pics of the rebuild. Also the attached web link sells them but at a hefty price.

http://www.gpopshop.com/hitachikits.html

Andrew

iTrader: (1)

I called them recently to see what they would charge to rebuild mine since they're in the next town over from me. The good news is that the person I talked to seemed familiar with the FD twins - at least he knew they were HT-12s. The bad news is that he said it would cost nearly a grand to rebuild them. That would be an expensive mistake if they end up failing especially considering that 99 spec twins are $2,000 or less. I've decided to just look for a set of good used ones.

Nathan Kwok

I'm probably the exception to the rule but I had my turbos rebuilt by Turbo City at 36k miles due to some leaking/smoking, and I am at 74k miles now and everything is still perfect. However, at that time they did warn me that the rebuildability was subject to the housing condition. It turned out my housings looked perfect and it was just the seals that were shot, making my turbos good candidates for rebuilds. I suspect a lot of the failed rebuilds were due to badly cracked housings, which cannot be repaired.

Xeros

what are the HT-12 units comparable to in GT garret turbo sizes?

Hi Im Simon

iTrader: (6)

I sent them an email regarding rebuilding the twins. They said it would cost 500+ shipping cost. anyone have any feedback for them?

I eventually plan on going single turbo later, but want to get the car running in the mean time.

DaleClark

iTrader: (55)

Talking with Bryan at BNR a while back, the big problem is the HT-12 center sections themselves. The clearances in the cast center section get hogged out and the center section is junk and they're not available new. You could rebuild the turbo but it would have a short life.

Best bet is just buying used twins. Good thing is a lot of low mileage JDM twins are out there, that's a killer option. You can easily get a good set of low mileage twins for $300 or so.

Dale

potatochobit

iTrader: (1)

that's right the center cartridge is the problem
it is also whats gonna smoke like puff the magic dragon
there are plenty of used manifolds to replace any cracked parts

repairing these cars is expensive and I hate my car right now, but you really shouldnt be surprised at paying 1000$ to rebuild two turbos.
if your car is in bad condition and you need to get to work you might want to first spend that 1000$ on a daily driver. I recently sold my toyota solara which was one of the first ones available for 1500$ and that was a steal.

this car is getting old and people going single turbo no longer have decent twin cores so I would try to find a JDM salvage first - though not sure where to get those anymore
2500$ for a new set is not really that bad if you plan to keep the car forever
though you might also want to save some money for an engine rebuild...

RotaryEvolution

iTrader: (30)

if they're low mile units and failed for ambiguous reasons then they can be rebuilt, just about anything beyond 75k miles is going to fail prematurely.

Hi Im Simon

iTrader: (6)

hmm... i have a set of working twins, but they have minor lateral shaft play. i was just thinking might as well rebuild it while the engine is out being rebuilt.

DaleClark

iTrader: (55)

All turbos will have some shaft play, that's totally normal. There is some space between the turbine shaft and the bearings that is normally filled with oil.

The only point where I'd look at doing something to the turbos is when you have chipped compressor or turbine wheels or they're barfing oil. If not, run 'em.

Many times you can also make one good set of turbos out of a pair of twins.

Spending $1000 to rebuild a set of stock turbos is foolish money. Put that money somewhere smarter, get a good used set, or go BNR's, 99 twins, or single.

Back in my FC days I've seen turbos rebuilt that then had problems shortly thereafter from a poor rebuild or from some problem the rebuilder didn't see at the time. I had an upgraded hybrid turbo that constantly barfed oil after several returns to the turbo shop - that was a royal pain. It's nice thinking you could easily and cheaply rebuild them and have nice fresh turbos but that isn't gonna happen. Closest you can come to that is some new '99 twins.

Dale

Hi Im Simon

iTrader: (6)

thanks for the input.

sc_frontier

iTrader: (3)

Will the stock twins eventually start burning oil? How would you know it is the turbo and not an oil seal in the engine?

Tem120

iTrader: (5)

Hey My twins have a little shaft play first turbo i've ever held in my hands so i'm completely numb and dumb to what is good or bad But I was told by other people that there was excessive shaft play.


the turbos dont seem chipped or anything . should I just leave them until they go bad ? if they go bad is there danger in it blowing my motor ? or will there be obvious signs that I need ot change them ?