Ethyl's Twins - Precision 6266 and 408 Ci

[wrp]

I appreciate you guys and gals following us on the Whipple build. We had a lot of fun with the Whipple and learned a lot of things. In all, over 750,000 views were logged against the Whipple build through several of the top sites. For five years now we have dealt with the Whipple and watched our build go from a one of a kind to seeing the COPO Camaro 4.0 Liter Upgrade using much of the same things we discovered, though to a much better result. I'd have to declare the Whipple a success. We decided to go a different direction after many hours of discussions with Mike@Whipple and Brent@CBM. Both of those guys helped us many ways over the years to overcome problems and come to solutions. The result is if/when I buy a Camaro, the 4.0 liter Whipple, 170mm TB and Crusher intake will be my choice.

For now, we wanted to go a different route. SNL Performance has long been heavily engaged in Turbocharged applications and we really wanted to apply the same level of effort to a Twin Turbo Setup with as much passion as we put the Whipple package together. Steve Addison of SNL had studied the twin turbo applications found in some of the rear mount technology and the APS kits. Over the years we have helped customers with Twin Turbos replace kit designs with larger turbos, we've ported Turbos and accomplished a dozen other tweaks. In many cases constraints in the customer goals limited the outcomes. On this build Steve made a special effort to understand my goals and then set out to have my fabrication done in a manner that is consistently high in quality and easily repeatable.

We chose to fabricate the installation so that it fit the existing 2004 GTO (Ethyl). We did not want to spend a large amount of time moving brake lines and electrical fuze boxes. If you are looking for exotic and innovative ways to tuck the ABS, we were not interested in solving the problem so you won't see it emerge here. My goals are somewhat more modest than with the Whipple. I am looking for a solid performing car in the 800 rwhp range with improved reliability and that we do not have to accomplish custom fabrication for the core system components beyond the initial Turbo build.

Steve chose the Precision units that have really had a positive reliability and quality reputation in the Honda and Supra world. After several communications with Aaron at Precision we settled on two options, twin 6266 or twin 6766. I chose the 6266 giving up potential growth for a better spool. The units have a 0.81 AR with a T4 flange.

Before we could get to the good stuff we had some cleanup to do with Ethyl.

First, the Mosier pumpkin with the Wavetrac 35 spline Diff could not handle the power the Whipple made. On the fourth 60% throttle pass the Wavetrac disintegrated. There were less than 1000 miles on the unit. At our power level, Mosier/Wavetrac agreed to fix the rear end one time but advised my they could not continue the lifetime warranty. After a very amiable conversation with a gracious representative from Mosier we opted to get our money back on the Wavetrac.

Chris Nichols at GForce Engineering recommended we try a Strange S-Trac. I had considered a spool which I had run successfully at this power level on the OEM differential. However, I broke an LCA while running the spool and prefer not to use one with the IRS. If the S-Trac cannot hold I am going to an SRA.

Next, the battery relocate done when the Whipple was on the car was my first and it was not well done. SNL has taken a couple of weeks to sort out the wiring problems we encountered as we began to bolt the Twins up. We stopped the install on the Twins and went through the entire car rerouting, wrapping, and reconnecting the wiring.

We also pulled the Nitrous kit. That may have been a mistake but for now we are just going to see what the Twins can do. I know where Waco is if I need to reinstall it.

In addition to the above, one of the driving factors on the twins was to have a hood back on the car. So I have bought my eighth hood and it is waiting patiently to be installed.

Most of the Fabrication and patch up work is done. We expect to start tuning next week. Here are a few teaser pictures of the car with the mockups and in some cases, the final fabrication, in place.

[wrp]

We pulled the heads just to take a look inside, 5000 miles later everything looked okay.










.

[wrp]

Here she is with her hood test fitted




.

[wrp]

After less than 1000 miles and 4 passes at 60% throttle the Wavetrac unit took a *** on me. At 900+ rwhp and 1110 ft lbs of torque and since I am using a trans brake, the lifetime warranty was only a one time fix warranty. It was a great unit I would highly recommend to anyone running less than 600 whp and no trans brake but I only bought it for the warranty, never considering it might not be able to hold up. We've replaced it with a strange S-Trac and I am looking forward to see how that is going to work.
Got the rebuilt 9 inch back with the Strange S-Track Differential
.



.

[camcojb]

That'll be a lot of fun. I had an APS twin kit on my 05 GTO with a built motor. Nowhere near the level of your build, but a heck of a ride.

[wrp]

There is at least one APS with 800+ right now. We upgraded the turbos on some of those kits. I am hoping for a little less time fabricating and a little more time getting in trouble

[camcojb]

Originally Posted by wrp

There is at least one APS with 800+ right now. We upgraded the turbos on some of those kits. I am hoping for a little less time fabricating and a little more time getting in trouble

My kit came with the larger GT3072's instead of the 28's. Still pretty small for a 402 LS2.

[MattO]

Has anyone checked to make sure you've been taking your meds, because you must be bat s**t crazy to give it even more power.


I bow to you sir

[wrp]

Originally Posted by MattO

Has anyone checked to make sure you've been taking your meds, because you must be bat s**t crazy to give it even more power.


I bow to you sir

As I get older the insanity seems to spread. Maybe its my memory going away. I will be actually stepping down about 150 rwhp and about 300 foot pounds of torque with this setup. Problem was wavetrac couldn't handle the power and wouldn't honor the warranty more than once. I decided on this config for two reasons. First, everytime I had a problem I wound up having to do custom fab work on things to fit the Whipple. Second, I am hoping this lower power setup will be less stress on the driveline and give me more opportunity to have fun.

Most of what you are hearing about Turbo power is coming from people with experience putting them on Hondas and Supras as singles. They multiply those reports times 2 and assume 1000 hp which I haven't seen anyone make with this size turbo on a v8. I saw one LSX 427 making 850 ish but that is the highest HP app I've seen short of 78mm/88mm or larger turbos which would have required major reconstruction of the car once cut up to fit..

I honestly am looking for a pre 74 roller to ditch the GTO and put the good stuff into. JMHO

[wrp]

Buttoned the engine back up today. Starting to find small things displaced over time, minor delays, yet irritating. For instance we sat on the fuel rails for three months before discovering the wrong thing was sent.