Early Callaway Twin Turbo Maintenance and Performance checkl

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boostedmaxPSI
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Early Callaway Twin Turbo Maintenance and Performance checkl

Post by boostedmaxPSI » Sat Aug 02, 2014 11:58 am

Hopefully we can make this a sticky at some point.

I have been asked from time to time by would be buyers and even new owners whose Callaway Twin Turbo might not be running as hard as it should what should they do to fix their issue or look at when buying. I can share what I have done with my B2K to provide a reliable vehicle that allows me to purposely look for those extra 3 inches of bumper and 11” wheels found on those other C4 Vettes : )

25 years of road action will have its toll on these cars given the technology at the time, ethanol blended gas we use today and heat cycles generated from WOT blasts and the occasional drives.

Maintenance items:

Fluids, I personally give all my new (used) car purchases 100% fluid changes. This gives me a known starting point with the car and I get to use the fluids of my choice
Injectors, I used GEN III 22lbs injectors to replace the factory units. The pre-92 injectors are not rated for Ethanol blended fuel and are subject to corrosion causing idle misses and hesitation on “tip in” among other issues. You can use a mulitmeter to OHM out each injector to find out if your current injectors are having any issues. There are parts of the country that still offer Ethanol free gas…
Spark Plugs, fresh spark plugs and wires are almost a must. I found with my car at 19,000 miles, the boots on the spark plug wires were worn from heat causing a spark arc/jump to the head creating a misfire. I upgraded my spark plug wires to a product called Live Wire which handles high heat situations and is low impedance giving maximum energy to the spark plug. Additionally, I added thermal heat sox to protect the spark plug boot to mitigate any future issues of heat degradation
• The oil scavenger pump on the ’88 and ’89 cars use an AN Earls fittings to connect and route the oil lines from the scavenger pump to the return tank near the K member. The Earl fittings were rubbing on my water pump pulley when I go WOT. I “upgraded” my system with bango fittings to match the style found on the ’90 and ’91 CTTC.
Distributor gear. Some cars will have brass gear and some will have a steel gear. The steel gear will only last about 10,000 miles before the hardened cam gear eats thru the softer steel gear on the distributor. Make sure you have the brass gear for longevity. The potential danger is the steel gear will literally wear to nothing and jump timing. I have been left on the side of the road twice because of this.
Coolant lines and Oil lines are easy to replace and should be done as soon as possible. These lines are 25 years old and are degrading with the heat cycles of the engine. I have upgraded mine to steel braided lines rated at 2,000 PSI and 450*. I found a local hydraulic line manufacture company to make me a new set. Callaway Cars still sells these as well.
Oil, my neighbor is in the oil industry and he’s a gear head. He has convinced me to start using Castrol EDGE Professional TWS 10w-60. This is the oil that BMW uses in their M Series cars. This particular oil is engineered for 15,000miles. It’s expensive, very expensive. But has served me well so far. Oil technology has come a long way from Mobile 1 15w-50. I personally use Mobil 1 in all of my other vehicles except the Callaway Twin Turbo.
Serpentine belt, good to have a new one and use the old one as a spare. Callaway Cars sells these for ~$40 and they are very specific to our cars. You will hard pressed to find this belt size at any local auto part store. I haven’t been successful…
• Check for boost leaks that might be robbing you of quicker spool and escaping pressure in the throttle body and hose clamps. I found that my throttle body was bleeding boost at the throttle plate’s shaft as they exit the throttle body housing.
Wastegate gaskets and cleaning, the wastegate gaskets will crack causing boost leaks in either the diagram side or the exhaust side. Depending on the type of leak you have the symptoms will range from laggy boost/spooling, uncontrolled boost or boost creep or simple exhaust leak before the 02 sensor causing issues with the ECM. The stainless steel wastegate lines run from the wastegates and join together at the top of the bellhousing into one line that goes into the upper manifold vacuum ports. These lines have been known to get clogged and create boost control issues.

Performance Upgrades:

BIG Wonderbar, this upgrade can still be done based on Callaway Cars product availability. Callaway Cars will make these from time to time when their stock is low. The kit consists of a new wonder bar and 3” piping along with new wastegate springs and gaskets. The flow is substantially better over the stock unit. The only difference between the two units is the inlet on the wonderbar. The old unit found on my ’88 chokes down to 2” with the cast aluminum piping. The BIG wonderbar keeps the air flow size to about 3”. Now the chokepoint has moved to the MAF sensor.
Exhaust, I currently have a 2.5” Corsa Sport system with high flow cats and an H pipe. All I can say is “YES”. This is a must have upgrade over the stock system or any after market system. The 2.5” system flows 144% over a stock system and has a nice rumble to it giving the car a Corvette sound again. You can clearly hear the turbos spooling up while the boost gauge is still on the vacuum side. Get ready to re-adjust the wastegate springs again. This exhaust can flow…
X Pipe. If you are currently running an aftermarket exhaust system that has dual pipe system, make sure that you have either an X pipe or H pipe. I found with my dual exhaust system without either X pipe or H pipe that my turbo spool was slow. This was the result of the exhaust pulsating and creating pressure back on the turbo. Once I added a X pipe, spool up became much faster.
• The microfueler is set by the Callaway Cars team using specialized bench test equipment to dial in the injector pulse width and timing vs. boost. I highly recommend that you never open nor touch the dash pods inside. They are super sensitive and as stated previously, you need the right test equipment to read the signal output response of the adjustment. That stated, the stock boost setting is 10psi and the microfueler can support about 12psi before going too lean. This will vary by location and car. Tune at your own risk.
AIC upgrade, 25 years of technology advancement has helped with getting more performance out these cars. 8 years ago I changed out my dated Microfueler with a new Aux Inj Controller. This allows me to manually adjust the setting point for turn on and how much fuel is to be used. The result is, this allows me to run higher levels of boost with the twist of knob. There are better units on the market today from my purchase 8 years ago that allow for fuel mapping and data logging. It might be time for me to upgrade again to ensure even safer boosting…
5 Speed, although this is an intrusive upgrade that most folks would be owners or current owners would not undertake. I can tell you this was probably the best thing I ever did to my 4+3 car. For the first few years of ownership, I felt like I was rowing a boat when shifting a transmission that dates back to the ‘60’s. to shift from 1st gear to 2nd, there was 7” of shifting. I used the Keisler TKO600 perfect fit solution which uses a Tremec 5 speed and a .68 overdrive. This allowed me to retain the stock bellhousing and clutch system along with the C beam and 3.07:1 gears. I’m not going to attempt to describe the installation process in this post, as mentioned it might not be the upgrade for most folks. It was for me, and I haven’t looked back. Again, this was probably the single best upgrade I have done to help with overall drivability and driver friendly shifting.
Cooling, my car came with a Callaway installed 3 row brass radiator. My radiator has been “rodded” and rebuilt when I first purchased my car. It’s time to do this again, however this time, I will forego the brass radiator for a DeWitt Aluminum 2 row with extra wide rows that out flow a 3 row system and upgraded fans for enhanced cooling. I live in Texas and just because it’s 100+ degrees outside, doesn’t mean I’m not going to drive my car. It’s not uncommon to see 230+ degree temps in these cars with the stock system in 100% condition. I think I can do better with an Aluminum setup. This is next on my list of upgrades. C4 Vettes are bottom feeders and trash and debris will get sucked up between the radiator and condenser. Inspecting and cleaning from time to time will help with cooling.
Custom Tune, I’m still using my Callaway supplied Phase IV tune with no modifications or program adjustments. I have spoken directly to the individual that Callaway used to program these tunes and there are additional performance benefits that can be had with a custom tune. I personally have not done this yet. Perhaps in the near future. Some forum members have used Hyperchip and even custom tunes. I hope these folks will chime in and post their experiences.
Cam, I spoke to Reeves Callaway about this once and he recommended a ZZ3 or ZZ4 cam to help “wake up” the car. My car is basically stock mechanically speaking. If the need ever arises that the motor needs to come out. This will be something I consider.

Lastly, get some tires. It is my opinion that the goal is to replace the tires due to being worn-out not because they are dry rotted from sitting.

I hope this helps would be buyers looking for a Callaway Twin Turbo car. I have owned LT5, LT1 and L98 (B2K) cars and I hear about the reliability of the B2K cars not up to par with the LT1/LT5 cars. With only 500 Twin Turbo cars built, with fewer then that actually driven, it’s tough to get a good sample to say whether that statement is correct or not. I can share from my personal experience; I have not had any such challenges in my B2K that did not exist in my LT1 car or LT5 car. Hoses, belts, plugs, plug wires, C4 Electrical Gremlins… These things simply exist in this model year Vette.

In 2013 I jumped in my Callaway Twin Turbo literally spur of the moment and drove it 1600+miles round trip in a very spirited manner and even raced it at the final destination. The only problem I experienced was a broken exhaust hanger; I still don’t understand that one to this day. I was intending on driving my LT5 car on this road trip but to prove a point of reliability, I drove the B2K instead and I’m glad I did so.

Feel free to comment or add to the list of items to check or upgrade, this is a list based on my personal experience of 8 years of active driving ownership. I have clocked over 50,000+ miles over 3 Callaway Corvettes with 15,000 of them coming from the B2K. Everyone will have a slightly different experience and I hope those experiences are shared so we can document them for future owners.

All this talk about CTTC...I'm going out for a drive now in hopes of finding a Z06 or Viper or Porsche or...

Callaway Chris
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Re: Early Callaway Twin Turbo Maintenance and Performance ch

Post by Callaway Chris » Sat Aug 02, 2014 1:26 pm

boostedmaxPSI wrote:Hopefully we can make this a sticky at some point.

Great summary, Frank. Thank you for consolidating into a great primer for new or prospective owners :cool

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SurfnSun
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Re: Early Callaway Twin Turbo Maintenance and Performance ch

Post by SurfnSun » Sat Aug 02, 2014 10:32 pm

Great post.

Over boosting- make sure your EGR valve is functioning properly. Remember a vacuum leak will keep your wastegates from opening, like a manual boost controller. If your EGR is stuck open, you will over boost.

Custom tune- I see the value in it. Remember Callaway had to warranty these cars. Was there power left on the table? Absolutely, just make sure you find someone who can burn for old school computers. When my car was tuned, the local LSx guy brought in someone to tune my car bc he didn't have the equipment to do it. Wideband is a must when dyno tuning IMO.

MarkSS
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Re: Early Callaway Twin Turbo Maintenance and Performance ch

Post by MarkSS » Mon Aug 04, 2014 5:18 pm

Thanks for posting this... as a relatively new B2K owner, it gives me a checklist of stuff to do over the winter if not sooner.

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Dakota Aero
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Re: Early Callaway Twin Turbo Maintenance and Performance ch

Post by Dakota Aero » Tue Aug 05, 2014 12:37 am

Please give information on:

1- scavenger pump specs and if operating normally what measurements to check for normalcy.

2-gil4seamentioned that valve seals will wear out. Please give information on the seals and what to watch for, best way to fix, etc.

Thanks, DA!

Cp

gils4sea
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Re: Early Callaway Twin Turbo Maintenance and Performance ch

Post by gils4sea » Wed Aug 06, 2014 7:21 am

CP,
I can help with #2. Usually, when valve stem seals start leaking, you'll notice some blue smoke coming from the exhaust on cold startups. Valve stem seals can be replaced without removing the heads through the use of compressed air in each cylinder which will secure the valves in place while the valve springs are removed. Once the valve springs are removed, the valve stem seals can then be replaced.
Gil
2010 CRM SC652

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Dakota Aero
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Re: Early Callaway Twin Turbo Maintenance and Performance ch

Post by Dakota Aero » Wed Aug 06, 2014 12:42 pm

Gil

Did I hear you say something like doing something for exhaust valve but not the intake or vice versa.?

Thanks!

Cp

boostedmaxPSI
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Re: Early Callaway Twin Turbo Maintenance and Performance ch

Post by boostedmaxPSI » Wed Aug 06, 2014 3:46 pm

Valve Springs and Seals I replaced my valve stem seals at 22,000 back in 2010. The condition will be blue smoke during start up and more notably after the car is fully warmed and just sat for about 10-20 minutes and more smoke is noticed then on cold startups. Callaway owners manual says some oil at startup is normal. When I replaced my Valve Seals, Callaway part# 502.00.2250 for the Intake and Callaway part# 502.00.2251 for exhaust. I also replaced the Valve Springs, Callaway part# 202.42.2400. The only reason I replaced the Valve Springs was due to cost. They were cheap and I was removing them anyway.

I will comment that Callaway uses a specific Valve Spring. I'm not sure what the load rate is or how it is different from a stock L98 but I can say they use dual valve spring solution.

Finally, when I did my valve stem seals, there was nothing left of the original units. The rubber had broken apart and rested in the rear of the head before the oil galley. I'm certain this was due to low mileage and the seals dried out.

Callaway Chris
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Re: Early Callaway Twin Turbo Maintenance and Performance ch

Post by Callaway Chris » Thu Aug 07, 2014 3:03 pm

Valve Guide Seals were notoriously bad on TPI engines. The seals often failed within a couple of years. The fix back then, was to install "umbrella" seals, which in speaking with Gil, he mentioned an oiling issue with that type of "fix" and as such, I would not perform such a thing on my own car. Rather, I'd replace them, like Frank and Gil have.

gils4sea
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Re: Early Callaway Twin Turbo Maintenance and Performance ch

Post by gils4sea » Thu Aug 07, 2014 7:39 pm

When I replaced the head gaskets on the Export CTTC, I used the valve stem seals supplied with the Felpro Gasket Set, which consisted of teflon intake seals which fit under the valve springs but over the valve guide and square "o" ring seals which are installed on the exhaust valve. The teflon intake seals are mushroom in shape. Chris, I believe the mushroom "fix" you were referring to consisted of a huge umbrella shaped seal that fit over the outside of the valve springs.
Gil
2010 CRM SC652

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