CTTC / B2K turbo removal and rebuild

Discussion of Corvette based Callaway Cars including: 1987-1991 RPO B2K Callaway Twin Turbo Corvettes (C4); Callaway SuperNatural Corvettes (CL-1/CR-1); Callaway C12; Supercharged Corvettes; Callaway C16; 6th Generation Callaway Corvettes (SC560, SC580, SC606, SC616, SC620, SC652); 7th Generation Callaway Corvettes (SC627/SC757); NEW Callaway C8 Corvettes - and more!
sjandras
4-PSI
4-PSI
Posts: 29
Joined: Mon May 17, 2021 10:01 pm

CTTC / B2K turbo removal and rebuild

Post by sjandras »

I'm starting a separate thread on the turbo removal, rebuild, and eventual reinstall for a 1988 B2K Callaway. I've searched all the forums going back 20+ years and there isn't really any detail for the DIY'er to show this job.

My process started with the basics:

1) remove convertible x-brace
2) drop the exhaust from the turbos back
3) drain the coolant and engine oil

Now the fun starts:

1) remove the banjo bolts using a 22mm wrench from both sides of both turbine housings. There will be some coolant mess.
2) remove the oil drain lines to the sump. A bit more mess here.
3) remove the wastegates, this greatly improves access to the header flange nuts.
4) remove the compressor inlet ducts and compressor outlets. The passenger side requires a long ball nose Allen wrench.
5) remove the oil feed lines on top of the turbine housings using a 9/16 shorty wrench.
6) start on the header flange nuts and be patient. One per turbo has direct access. I ended up using a combination of 17mm tools: a short swivel socket, a traditional crow foot socket, and a flange nut crowfoot. I had to use the flange nut crowfoot for the inner forward nut on the passenger side because the casting is so close to the nut. Most of the nuts will be 1/6 turn at a time all the way off.

No need to drop the starter or to drop the manifolds. So far I'm into it for about four hours excluding the prep work, most of which was spent thinking and strategizing (and a fair amount of cussing).

I also spent quite a but of time calling around to find a rebuilder. I thought it would be easy, just call Rotomaster. Not so much.... After leaving four voicemails, I was finally able to catch the rebuild guy. They have decided that they are out of the Callaway rebuild business, they absolutely will not do anymore of them after some recent bad experiences and obsolete parts.

After a few more dead-ends, I talked to Charlie at Evergreen. He has everything except bearings and they can be made if needed but are very expensive. Hoping mine only need seals, we'll see in a few weeks! I'll post further updates as I get them back and start reinstall.
Attachments
20231027_094820.jpg
20231015_130433.jpg
20231027_094843.jpg
20231027_095522.jpg
20231027_095611.jpg
User avatar
Dakota Aero
VIP COG Brother
VIP COG Brother
Posts: 761
Joined: Fri Nov 28, 2008 10:24 pm
Location: Black Hills

Re: CTTC / B2K turbo removal and rebuild

Post by Dakota Aero »

Excellent ! Thanks for helping the Brotherhood! :help Are there more pictures of the steps you can share?

DA
sjandras
4-PSI
4-PSI
Posts: 29
Joined: Mon May 17, 2021 10:01 pm

Re: CTTC / B2K turbo removal and rebuild

Post by sjandras »

Dakota Aero wrote: Fri Oct 27, 2023 12:10 pm Excellent ! Thanks for helping the Brotherhood! :help Are there more pictures of the steps you can share?

DA
I don't have many good pics in process, because I was focused on just getting them out and it was a pretty messy job. I'll take some documentation pics as I start to reassemble with cleaner parts.
User avatar
SurfnSun
Site Admin
Site Admin
Posts: 2340
Joined: Wed Aug 27, 2008 9:44 pm
Location: Central FL
Contact:

Re: CTTC / B2K turbo removal and rebuild

Post by SurfnSun »

Wow Rotomaster didn't stay in the rebuild business very long. That is disappointing. They only did a few sets and called it quits.
callaway4fun
VIP COG Brother
VIP COG Brother
Posts: 390
Joined: Wed Aug 27, 2008 8:12 pm

Re: CTTC / B2K turbo removal and rebuild

Post by callaway4fun »

That sucks that they will not support their product anymore. I guess finding turbos is going to be a big problem now
sjandras
4-PSI
4-PSI
Posts: 29
Joined: Mon May 17, 2021 10:01 pm

Re: CTTC / B2K turbo removal and rebuild

Post by sjandras »

callaway4fun wrote: Fri Oct 27, 2023 4:50 pm That sucks that they will not support their product anymore. I guess finding turbos is going to be a big problem now
I'm optimistic about what Charlie at Evergreen can do based on our few phone calls and what I've read. He seems to know these turbos well and has done a bunch of them. He also has a great reputation in the Porsche forums. He indicated he can fix anything on these very reasonably, except the bearings which can be custom machined if needed. I'll keep the group posted.

My goal in starting this thread is to make people less afraid of these cars, they are machines that can be maintained and fixed without breaking the bank. I hope....
User avatar
1988Callaway#16
5-PSI
5-PSI
Posts: 80
Joined: Mon Jan 01, 2018 10:50 pm
Location: Bellevue NE

Re: CTTC / B2K turbo removal and rebuild

Post by 1988Callaway#16 »

Thanks for the info! Kevin
632C2
4-PSI
4-PSI
Posts: 31
Joined: Mon Oct 20, 2008 3:38 pm

Re: CTTC / B2K turbo removal and rebuild

Post by 632C2 »

Back on 5/16/2005 Charlie rebuilt both of the turbos on my 1990 Aerobody and they are still operating perfectly today. His work is incredible!

The car now has a little over 2200 miles on it! Last time I had it on my DynoJet it made over 720 rwhp.
sjandras
4-PSI
4-PSI
Posts: 29
Joined: Mon May 17, 2021 10:01 pm

Re: CTTC / B2K turbo removal and rebuild

Post by sjandras »

The turbos are through rebuild by Charlie (Evergreen Turbo). I can't say enough good things about him. He sent play-by-play photos of the rebuild process as he was going through them, it was great to watch! Great news is that all the hard parts cleaned up like new, right on spec. He has the original reference data for these turbos, so you know what you're getting.

The only issues he saw were the carbon seals on the impeller side of the shafts were gummed up and sticking. He referenced a change to Mobil1 specs that happened around 2008, where it is no longer approriate for turbo cars because you get this kind of varnishing. He has seen the same on all the Porsche turbos he builds and can tell when they've been running Mobil1 vs something like Brad Penn oil. I'll need to do some more research on that before spring.

I've attached a couple of his pics below just for reference of the great work that he does. Can't wait to get them back and get it all bolted together. While apart, I also replaced the manifold flange studs with some grade 10.9 studs from BelMetric that appear to match originals exactly.
Attachments
IMG_2885.jpg
722891090.jpg
722891731.jpg
722893926.jpg
TrippleLift
Guest
Guest
Posts: 5
Joined: Sat Dec 18, 2021 6:42 pm

Re: CTTC / B2K turbo removal and rebuild

Post by TrippleLift »

I have to pull off my turbos on my 87'. Reading around I think they are from IHI RHB52. They seem to be common enough, think any turbo shop around Ct can habdle rebuilding them?
TrippleLift
Guest
Guest
Posts: 5
Joined: Sat Dec 18, 2021 6:42 pm

Re: CTTC / B2K turbo removal and rebuild

Post by TrippleLift »

Well I have been inspired to start working in my 1987 #184, Finally got some sort of lift in the garage.
632C2 wrote: Mon Oct 30, 2023 10:03 pm Back on 5/16/2005 Charlie rebuilt both of the turbos on my 1990 Aerobody and they are still operating perfectly today. His work is incredible!

The car now has a little over 2200 miles on it! Last time I had it on my DynoJet it made over 720 rwhp.
I would love to see 500 whp. Think you can point me in the right direction for tuning this thing? Like stock injectors, should I keep the microfueler? Can the fuel pump keep up with more power?

I need to start my own thread for this car.
632C2
4-PSI
4-PSI
Posts: 31
Joined: Mon Oct 20, 2008 3:38 pm

Re: CTTC / B2K turbo removal and rebuild

Post by 632C2 »

TrippleLift wrote: Sun Dec 03, 2023 5:53 pm I would love to see 500 whp. Think you can point me in the right direction for tuning this thing? Like stock injectors, should I keep the microfueler? Can the fuel pump keep up with more power?

I need to start my own thread for this car.
I've done quite a bit of work to this car. I have two fuel pumps, a pair of huge injectors for the turbos, a full 3" exhaust system, a Split Second Additional Injector controller, and tons of runs and Tuner Pro tuning on my DynoJet.
User avatar
SurfnSun
Site Admin
Site Admin
Posts: 2340
Joined: Wed Aug 27, 2008 9:44 pm
Location: Central FL
Contact:

Re: CTTC / B2K turbo removal and rebuild

Post by SurfnSun »

TrippleLift wrote: Wed Nov 29, 2023 9:01 pm I have to pull off my turbos on my 87'. Reading around I think they are from IHI RHB52. They seem to be common enough, think any turbo shop around Ct can habdle rebuilding them?
Yes any good shop can do those. They are still in production and parts would be readily available...I assume.
User avatar
SurfnSun
Site Admin
Site Admin
Posts: 2340
Joined: Wed Aug 27, 2008 9:44 pm
Location: Central FL
Contact:

Re: CTTC / B2K turbo removal and rebuild

Post by SurfnSun »

632C2 wrote: Mon Oct 30, 2023 10:03 pm Back on 5/16/2005 Charlie rebuilt both of the turbos on my 1990 Aerobody and they are still operating perfectly today. His work is incredible!

The car now has a little over 2200 miles on it! Last time I had it on my DynoJet it made over 720 rwhp.
720!! Wow.

Good to see you checking in!
sjandras
4-PSI
4-PSI
Posts: 29
Joined: Mon May 17, 2021 10:01 pm

Re: CTTC / B2K turbo removal and rebuild

Post by sjandras »

I have the turbos back in-hand and I'm still slowly working on the car. I pulled a few more hoses out last night to have them re- made. I am going to re-route the scavenge pump return line to fix a tight clearance issue to the water pump pulley (it was rubbing when i got the car!) and the power steering lines. My nightmare is seeing this thing burn down due to a brittle old line breaking. I'll post a few more pics as I go.

I have no affiliation and have never met the guy, but Matt Garrett (ultraslow) has been busy with his C4's. Quite a collection and some pretty good technical content in his videos. No rattle cans involved!

https://youtube.com/@gm-classics?si=GFuzRYHkoxWP8e8s
Attachments
20231209_145340.jpg
User avatar
SurfnSun
Site Admin
Site Admin
Posts: 2340
Joined: Wed Aug 27, 2008 9:44 pm
Location: Central FL
Contact:

Re: CTTC / B2K turbo removal and rebuild

Post by SurfnSun »

sjandras wrote: Sun Dec 10, 2023 10:06 am I have the turbos back in-hand and I'm still slowly working on the car. I pulled a few more hoses out last night to have them re- made. I am going to re-route the scavenge pump return line to fix a tight clearance issue to the water pump pulley (it was rubbing when i got the car!) and the power steering lines. My nightmare is seeing this thing burn down due to a brittle old line breaking. I'll post a few more pics as I go.

I have no affiliation and have never met the guy, but Matt Garrett (ultraslow) has been busy with his C4's. Quite a collection and some pretty good technical content in his videos. No rattle cans involved!

https://youtube.com/@gm-classics?si=GFuzRYHkoxWP8e8s
The wrong belt will cause the lines to hit the pulley. You have to use a Callaway belt.

The 91 b2k got different routing lines from the scavenge pump. The eliminate the close tolerance and are a better design all in all. We had a former forum member update his 88 to the 91 style.

Ultraslow does good work on his b2ks. The numbers he professes are wildly exaggerated with no dyno numbers to back them up, but he does seem to turn a good wrench.
sjandras
4-PSI
4-PSI
Posts: 29
Joined: Mon May 17, 2021 10:01 pm

Re: CTTC / B2K turbo removal and rebuild

Post by sjandras »

Agreed re: the belt. I replaced it when I went through the water pump and rad replacement. It's as short as it can be and still get it on, but the clearance is still way too close for me. I'm having a new hose made and switching to an ORB banjo fitting similar to what the later cars had as part of my fixes. I've been doing a lot of bringatrailer photo album benchmarking to learn all the subtle changes that happened after 88.

I talked to Wayne at Callaway yesterday to order all the gaskets and a few random things, it's amazing the detail that guy can pull up. For example, my car was missing one of the four oddball sheeetmetal screws that hold the scavenge sump to the frame, and he knew immediately what I needed and found the bin in the stock room. Great service!
TrippleLift
Guest
Guest
Posts: 5
Joined: Sat Dec 18, 2021 6:42 pm

Re: CTTC / B2K turbo removal and rebuild

Post by TrippleLift »

I'm working on pulling mine now, off of a 1987. I just got all the bolts on the headers loose, as I was hoping you could just drop the headers and pull them out from the bottom. I doubt my abilities to get the bolts that connect the turbo to the header off.
User avatar
SurfnSun
Site Admin
Site Admin
Posts: 2340
Joined: Wed Aug 27, 2008 9:44 pm
Location: Central FL
Contact:

Re: CTTC / B2K turbo removal and rebuild

Post by SurfnSun »

Turbo removal is no small task, most don’t remove the manifolds
TrippleLift
Guest
Guest
Posts: 5
Joined: Sat Dec 18, 2021 6:42 pm

Re: CTTC / B2K turbo removal and rebuild

Post by TrippleLift »

I'll make my own topic/help thread tonight, but for now ill post here. What is this line for on the exhaust and how do I remove it. Its on the rear cat and I see some type of crimp on what appears to be a flare?
Attachments
20240615_183130.jpg
20240615_183123.jpg
Post Reply