8000 RPM LT4, inside a Katech powered ZL1
 

Good Morning everyone and happy friday! My name is Zach and I am an engineer over at Katech in Clinton Township, MI. If you don't know who Katech is, we are one of the premier performance engine and vehicle builders that have been in the industry for more than 40 years. Our roots are deep with Corvette Racing, a majority of our innovation comes from our experience developing race engines with GM.

I am in the engineering department and also do a lot of work with our vehicle shop. My goal when working with customers is to make sure they understand the type of package they are getting into, and it meets all of their expectations upon pickup.

With that said, we do a lot of cool development work in the shadows to ensure we are competing with the best of the best in this exponentially growing industry. I purchased a 2018 ZL1 1LE personally with the original goal to make it our version of a gen 6 Z/28. Take the LT4 out, put a dry-sumped naturally aspirated 427 in, and let it rip on the track. After driving the supercharged motor on track and overlaying some dyno data between a few of our engine packages, I determined that I will save that project for another vehicle because this car had to stay with a supercharged engine.

I set the new goal to develop a high-rpm package with a relatively stock engine that could be used for multiple applications. The new target was making 800whp at 8000 RPM. In this thread, I plan on posting the engineering behind what it takes to do something like this, the contents of this package, and the results it produced.

To start, here is a picture of the car when I first purchased it. I bought this from a former road racing form member Mark of W2W racing. It had 3500 miles on it from a dedicated life at COTA. It was gutted with AP racing brakes, a cool suit chiller, a trunk meth tank, and some mild bolt-on/exhaust work. My first project for the car was reverting this back to stock with the interior, trunk, and fueling modifications. I removed the meth system, I reinstalled all of the factory interior, and put the stock brakes (for the time being) back onto the vehicle. Afterwards, I had our calibrator tune the vehicle and it made a stout 600rwhp with the only modifications being a rotofab intake, ARH headers, and Borla S-Type exhaust.

https://i.ibb.co/m6N3hFS/IMG-E4434.jpg

I will continue to update this post with discussion topics, results, and finding as I get the time. This car is levels better than my 5th gen, and I can't wait to get out to some events with all of you

Cool.

I’m in for all the updates you want to post OP. Can’t wait to see the finished car.

Subscribed :)

Good Morning guys, happy monday! The first step to doing any of these types of projects is having a good cup of coffee and getting right into the teardown process. Here are some pictures of the car when we pulled the engine.

Whenever doing any work involving tearing into the stock shortblock (any sort of cover, oil pan, etc), we highly suggest pulling the engine. These engines are glued together with RTV unlike their older LS siblings. The issue with this is that it is very difficult to get the engine to reseal properly without thoroughly cleaning everything before reassembly. When you pull these apart in the car, it is an oily mess that almost guarantees you to have oil leaks during the reassembly process.

Another issue is with the large single bolt camshaft. You are suppose to brace the back of the camshaft when torqueing this bolt. If you do this in the car, you are putting all of that torque through the timing chain. Doing so makes you at risk of having a timing chain failure even when you have a stronger aftermarket chain like our C5R chain.

Vehicle on the hoist
https://i.ibb.co/xC2bLt0/IMG-5697.jpg
Rough disassembly
https://i.ibb.co/qkhsvcb/IMG-5704.jpg
Front bumper off, further disassembly
https://i.ibb.co/r2ygkf3/IMG-5706.jpg
Engine on the lift table
https://i.ibb.co/ZT2vZRk/IMG-5709.jpg
LT4 longblock on an engine stand
https://i.ibb.co/V2KsRSz/IMG-5714.jpg

Good Afternoon guys,

Here are some pictures from the teardown. For this build, this involved getting the engine down to a bare block. The only modification that I plan on doing to the shortblock is adding ARP connecting rod bolts to the factory rods. We have tested the factory rotating assembly to nearly 1500HP around 7000rpm, somewhere between 1300 and 1500 we began to bend rods. I am adding ARP connecting rod bolts to ensure that the factory rod bolts do not break when spinning this engine at 8000 RPM. I am testing no-mans land on this stock bottom end, so I would not take this as "Katech's signoff to spin the SBE to 8000 RPM w/ ARP Rod Bolts", but take it as "This is what Katech's engineer Zach is doing in his personal project car"

Supercharger Off
https://i.ibb.co/XXfBsx2/GM8A1124.jpg
Factory Valvetrain
https://i.ibb.co/sqpWMT0/GM8A1149.jpg
Cylinder Heads Off
https://i.ibb.co/SJwKnBr/GM8A1169.jpg
Piston/Rod Assembly Removal
https://i.ibb.co/PNcTLSc/GM8A1193.jpg
Piston/Rod Assembly Removal
https://i.ibb.co/PGJT9wY/GM8A1198.jpg

Following! Love this thread :burnrubber:

Hey Zach! Following this thread too.

So did I read this right or wrong? ARP connecting bolts only? Further down you mentioned adding ARP connecting rods.

Mistype, good catch! I edited it, It is only ARP connecting rod bolts

I am so stoked for this build!!

Ken

Watching this with great interest Zach. I myself am having a BLAST road racing my LME 416 NA SS 1LE HYBRID. As a matter of fact I call it my 2019 Z28. The ONLY time it went into REDUCED POWER mode is when I broke an AC belt and it tore a wiring harness off the front of the engine. Water temps even at 105 degrees outside down here and 30 minute sessions NEVER gets about 10 degrees warmer than normal.

It will rip, thats for sure :cool:

AC belt breaking is no fun! by any chance was the AC accidentally engaged while racing? or was it turned off the entire time? Very cool build. I will eventually build a Z/28 spec build when the time is right

Very interested in this one, thx for posting Zach

On the stock cars, the AC automatically turns off under power demands, like racing. Many cars/manufacturers are doing this these days.