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C6 Corvette ZR1 & Z06General info about GM’s Corvette Supercar, LS9 Corvette Technical Info, Performance Upgrades, Suspension Setup for Street or Track
Soon. I am still putting some miles on this new motor to break it in. I am dropping it off with my turner on December 26th to finish up my N/A tune and Nitrous tune.
I have a new TSP cam that Pat G spec'd for me and I will most likely switch this cam next week as well. I am pretty **** about how my car drives so I am trying to get a max effort N/A with what I consider good drivability. I am also going to switch my plugs and I think that I have a vacuum leak that is causing some backfiring that needs to be addressed.
However, if all goes well, I should have some dyno numbers within the next 2 weeks. I will share my N/A dyno as well as my dyno on a 300 shot once I get them.
What's the new cam's numbers?
"Good drivability" is so objective, it's nearly impossible to define....
I did not like how my car drove with what I consider an aggressive camshaft, and spent two solid years trying to make it behave better with tuning. Gave up and pulled it out last spring. Went with a different camshaft and am much happier. Didn't take much effort at all to re-calibrate it for the smaller cam either.
It does not pull as hard over 4500 as the first cam did, but it pulls harder off idle to ~3500.
An acquaintance that I was sorta helping out with tuning and engine configuration for his Z06 just sent me an update with dyno sheet. He was tired of the BS you get from a big camshaft and wanted his Z06 to drive near stock. Went with a very mild EPS camshaft (226/236 .630/.605 118 lsa) and it still made 551/510 rwhp.
"Good drivability" is so objective, it's nearly impossible to define....
I did not like how my car drove with what I consider an aggressive camshaft, and spent two solid years trying to make it behave better with tuning. Gave up and pulled it out last spring. Went with a different camshaft and am much happier. Didn't take much effort at all to re-calibrate it for the smaller cam either.
It does not pull as hard over 4500 as the first cam did, but it pulls harder off idle to ~3500.
An acquaintance that I was sorta helping out with tuning and engine configuration for his Z06 just sent me an update with dyno sheet. He was tired of the BS you get from a big camshaft and wanted his Z06 to drive near stock. Went with a very mild EPS camshaft (226/236 .630/.605 118 lsa) and it still made 551/510 rwhp.
This cam was cut by TSP with their TSP353 custom lobes using 8620. Pat G said that he is making more power with their cams and recommended that I go with TSP, which I did.
My tuner should be e-mailing me the Winpep files today.
I have been through a handful of cams to get my car to drive like I want it to and it is now perfect to me. I can drive in 6th at 1200 rpms and it won't surge. However, it feels like it has more torque than any of the other cams that I used. I highly recommend Pat G to spec a cam if you are looking for a custom cam. I haven't driven it hard at high rpms so I can't speak to what the power is like at 7000 rpms, but it is great driving on the street, which is what I was looking for. That is why I like a NA/Nitrous setup because you can get the best of both worlds.
I also plan to road race this car some and I did not want a super aggressive cam. My car is street driven 80% of the time and the other 20% will be spent at 1/4 mile, 1/2 mile and road race events.
I'm really curious what is meant by rod "bushing?" Built several engines and I've never heard of a rod bushing. Maybe another term for piston pin??? Excuse my ignorance.
I'm really curious what is meant by rod "bushing?" Built several engines and I've never heard of a rod bushing. Maybe another term for piston pin??? Excuse my ignorance.
In the small end of the connecting rod there is typically a bronze or brass bushing to help keep the piston pin from galling. There are a few exceptions to this in some race applications but it requires either a very hard piston pin or one that has been coated with something like a DLC coating to do this.
When you might see either detonation or possibly a case like lifting the head you will generally see even material transfer from the bushing to the pin or from the piston to the pin when they start to flex, which is why attention must be given to the clearance at the pin boss as well as the material type and wall thickness of the pin.
The bushings can be replaced, or in most cases just honed to the next size or you can use a custom pin so as not to have to re-bush the rod.
In the case of the LS7 stock small end is 0.9252 and most pins sold for LS are 0.927 so it is easy to use an off the shelf pin and just slightly oversize the pin boss in the rod and clean up the bushing to fit a slightly larger pin without having to go through the cost to re-bush the rod and risk damage to the OE Ti rods in the process.
Long story short:
HPR 454 with forged crank, rods and pistons for about 7k
Rebuild LS7, reusing rods (bushed) and crank for about 5k
I suspect that I can probably sell my LS7 for more than the cost difference.
If I go with a 454 and reuse my LS7 heads will I notice much difference with how this engined revs vs. my LS7. If not, then I see no reason to rebuild my LS7.
In the small end of the connecting rod there is typically a bronze or brass bushing to help keep the piston pin from galling. There are a few exceptions to this in some race applications but it requires either a very hard piston pin or one that has been coated with something like a DLC coating to do this.
When you might see either detonation or possibly a case like lifting the head you will generally see even material transfer from the bushing to the pin or from the piston to the pin when they start to flex, which is why attention must be given to the clearance at the pin boss as well as the material type and wall thickness of the pin.
The bushings can be replaced, or in most cases just honed to the next size or you can use a custom pin so as not to have to re-bush the rod.
In the case of the LS7 stock small end is 0.9252 and most pins sold for LS are 0.927 so it is easy to use an off the shelf pin and just slightly oversize the pin boss in the rod and clean up the bushing to fit a slightly larger pin without having to go through the cost to re-bush the rod and risk damage to the OE Ti rods in the process.
looks like those head dowels that hold the head in place
FYI... The stock LS7's TI rod uses a split wrist pin bushing. Under severe rod loading the split bushing has been known to squirm and ultimately deform. Katech replaces that bushing with a solid bushing which cures the squirm and deformation issues.
I decided not to replace my rod bushing as I had a hard time finding an example where a failure was caused by this bushing.
I would absolutely choose the same build again and I am very happy that I reused the TI Rods and OEM crank with light weight forged CP pistons. I think that I reduced the rotating assembly by a few lbs and I can certainly tell during acceleration. I am using a relatively conservative cam because I wanted to be able to cruise in my car without having to deal with any surging. I can drive at 1200 rpms in 6th and it won't buck or surge at all.
However, I also wanted to be able to road race my car some and also get into the upper 170's or low 180's in 1/2 mile event on Nitrous and I can absolutely do it with my setup. My cam makes lots of power under the curve and it will hold 580whp to redline. IMO it is perfect for my goals.
There is one thing that I would have done different and I am going to have to spend some more money to change. I originally went with a nitrous plate setup because I didn't think that I would want to run more than a 150 shot (laugh). I can safely run a 250 shot right now, but I can't go any higher with a plate system. I plan to switch to a direct port setup in the next few months so I can run whatever shot I want to run. If anyone is interested an an almost new Nitrous Outlet plate for a MSD intake, a set of nitrous and fuel solenoids, hardlines and brackets for solenoids, they will be for sale shortly
Last edited by lamboworld; 03-05-2018 at 05:43 PM.
I had my tuner put my car back on his dyno to just make sure that my tune is spot on because I have a few upcoming road race events and a 1/2 mile event. I plan to have my car on some type of track a few time a month through September. My final numbers are 564whp/502wtq with this cam 236/250 .635"/.635" 115LSA +4. My car drives fantastic and will cruise in 6th gear as low as 1400 rpm's without surging. This is a custom cam that was spec'd by Pat G based on the goals that I gave him.
My previous cam was a Mamo spec'd cam 236/250 .650"/.650" 114LSA +3 This cam was in my LS7 block and it put down 580whp/515whp.
These dyno numbers are from the same dyno and the same tuner. Both cams drive good, but my current cam will cruise a little better in 6th gear.
I might switch back to the Mamo cam or maybe even a little more aggressive cam but I plan to drive on this one for at least this year.
With a 250 shot through a Nitrous Outlet plate setup I put down 780whp/850wtq. It actually probably puts down a little more whp than what is shown on the dyno but all I asked my tuner to do was to make sure that tune was good to go when on the bottle.
Lastly, my engine runs much quieter since I switched from an LS7 block to a TSP Darton Sleeved block and Johnson 2110 lifters. I have decided to switch from the B&B Fusion Gen 3 to the Borla ATAK exhaust. This ATAK seems to be pretty loud but it sounds really good based on what I have heard.
12-21-2017, 11:04 AM
