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Taking a bone stock C6 Z06 and trying to make it faster
about 6 months ago I purchased a c6z with the intention of building a street car that would be competitive in time attack, autocross and maybe the optima ultimate Street car series.
It has turned into a bit of a project and I thought I would share some of that here.
I bought this car after considering other cars up to about $30k: cayman, mustang, Camaro, Elise, 996 and a few others. But the corvette just seemed like the best on track while having a high “not everyday” factor on the street.
I found a good deal on an 06 and got it, even though the miles were high.
I immediately decided to partly address the oil starvation issue (although I didn’t fully understand that it wouldn’t be an issue for me unless I ever got to high lateral loads). I had the oil tank enlarged and installed a baffle in it. I hadn’t wanted to wrench on this car ever (well, at least not for a little while) but this was a good example of what is called foreshadowing.
I also learned about the npp and the switches that manually manually control them and figured it could only help with power and would sound better so I grabbed one used from here.
I put about a tank tank of gas through it when I pulled it into the garage for the last time 5 months ago.
Lost on this once, since all you need to do is change out the tires to R compounds, and the car is fully track ready as is.
As for the oil starvation in the dry sump motors, 10.5 oil tank solved this problem for long high G corners.
Also, until you can play rev ranger through a entire track (technical sections as well) while holding the car to to it's handing capabilities edge, nothing need to be mod'd on the car.
If you are trying to throw money at the car, isntead of at your driving skills instead, to make you and the car faster on the track, your wasting money.
I'll be blunt and a T1 C6 vet is only making around 600hp, and the amount of money spent to increase down force and handing on the car to just use the extra 100hp in a skilled drivers hand, is the only reason that the mods are done in the first place.
Hell, I'll take it a step farther, and in the hands of a novice driver, they are faster around a road coarse track in a Z51 option car, then a Z06 instead. The reason, the z51 will give plenty notice when you are hanging it to the edge, while the Z06 gives now when you are getting close to its edge, and just bites you hard when you push it past the edge instead (puts you in the ditch).
So from the start, post your lap times around a high speed road course like Laguna Seca running R compound tires as your bench mark, then as you are making mods, post your times again with each mod.
The thin cylinder walls of the ls7 427 can’t hold blown pressure that well.
If 505 hp isn’t enough then buy a car that has more like a ZR1
If you are keeping the c6 z06 then just have cow send you cow booster to remap the throttle position sensor...and it ll be more reactive to your throttle inputs.
I think that’s what you are looking for...as it’s 505 hp in 3100 lbs....
GM dumbs the initial throttle response down big time...to keep their lawyers happy...
The cow booster creates a more linear throttle response and i believe that’s what your missing.
After the 200 dollar mod to remap the throttle response and if your still not satisfied...remove the mod, get your money back and just sell the car..
It’s a mid 20 grand car maybe 30 grand ....with high mileage..
Leave as it is...for the most part...or sell it..
Top speed 198 mph..zero to sixty in the mid 3s...
It’s the throttle response you need to modify...that’s what your missing.
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Last edited by JerriVette; 05-24-2018 at 02:38 AM.
Now I had done some research before I bought the car and had heard about some people having head and valve issues and others had talked about brakes overheating and the oil issue had come up but I figured I would be just fine.
Well, I did all the research after the fact and not before so I found myself looking at a few not-cheap issues that I felt it would be wise to address.
I also had been talking to some friends who have more experience than I in the professional racing world and they suggested that some companies might be interested in helping with the build so I decided that I had nothing to lose and started to contact those that seemed like they were very good to gauge their interest.
It was difficult for me to do as I do not like to ask for help. But I found that many companies were very willing to help. Luckily for me, my job is a big draw for this. For almost 20 years, I have been working in the film and television world as a professional stuntman, and for the last 10 or so, primarily as a stunt driver.
I have been very fortunate and done some really fun jobs, including doubling Keanu in both John Wick movies driving the Mustang and in Baby Driver doubling the lead, Ansel. I have done a bunch of other movies that have not received the notariety that these have such as Drive, Hit and Run and The Last Stand.
For those who haven’t seen The Last Stand, the villain (whom I doubled) drove a c6 zr1. I can’t say that I fell in love with the car on the show and had to have one, but I did really enjoy it and it is very funny to me that I have a c6 now.
For those interested, you can see some of the stuff I’ve done here: http://www.imdb.com/name/nm0296758/?ref_=fn_al_nm_1
I realize that the stuff we do on screen does not translate to fast on the track. But I spend a lot of time training in a lot of different areas, from stunt driving to drifting to stage rally to autocross to road racing. And I have found that I can put down a pretty decent lap.
I have taken my Nissan 240sx to the Camarillo auto cross twice and set the official fast time of day in it. In full disclosure, a guy in a c5 one time and another in a 350z the second time both were a bit faster but their times for some reason didn’t count - I assume they were connected to the organizer. So second-fastest technically
It was mentioned that I should have got a zr1 if I wanted to go fast, and maybe they would be faster around a track, but there is a serious cost associated with that car and I simply could not afford the cost of admission. In retrospect,with the amount I have sunk into this, I should have bought one already built and been ahead of the game, but I do enjoy building cars and driving something that I have built myself, so it isn’t a the worst decision I’ve made
i also should clarify the title a little - i didn’t set out to make the car faster per se, but rather I wanted to address the issues that seem to come up that could either end a day early or fail and cause damage to either my wallet or myself .
anyway, I will share which companies agreed to help so that there is full disclosure. I’ll continue soon, but leave by saying that I consider myself extremely fortunate that American Heritage Performance is pretty close by, is an amazing shop and agreed to help out with the build a little. So operation queen of hearts started and off went her heads!
Congrats on the purchase. The C6Z is still to this day a legendary sports car. With very minimal effort it can become an absolute monster.
I think you're on the right path of addressing known issues and replacing things as you go. Any new (used) car purchase is trail and error for the first couple of months of ownership.
As others have mentioned sometimes throwing good money at the wind doesn't always pay off. If it isn't broke don't fix it. Good luck and happy modding!
Low down on the valve problem in the Ls7, it all boils down to a rapid wear/less than ideal fit of the valve stems to the valve guides causing a great deal of lash/slop of the valve stems to the valve guides.
The OEM valves are sodium fulled, so as the valves are no longer cleanly returning to the seats square on closer do the excess slop between the stems and guides , this can cause the valve head to snap off the stem, into the motor, and destroy the motor.
So the solution is a two part one on a motor that will rev to 7K, being the first it to replace the valve guides so they fit the valve stems correctly. The second it to replace the sodium filled valves with solid SS valves at the same time as the guides, so they can can be matched to the guides. Hence It's not due to the SS valves begin better, it due to the fact that the guides to stem fit will wear again, and with a solid SS valve, less likely to snap the head off the valve instead.
As for the #1 mod to the C6 (all C6's), it's all has to do with them having lift at speeds. So a couple of ways to pull such off, but its getting the car to have down force at speeds, the best bang for the buck to improve handling from the start. To be blunt, the only reason that the T1 suspension (needed parts can be bought OEM from GM) works on the T1 cars, is due to the amount of down force the T1 cars have. Without that amount of down force, the car would be over sprung with a T1 suspension parts, and you will never be able front weight transfer for any corner as well.
At this point in the story, I was talked into doing a Cam at the same time as getting the heads fixed. So I started pulling the stuff off to allow access to the cam.
It seemed that everything I pulled off I thought I should replace because of the high miles and my goal to prevent mechanical failures on the track.
I got a brand brand new newer style water pump from a guy on the forum who pulled it off of a new crate motor. I got a new set of silicone hoses for the newer style from another forum member.
Dewitts radiator said they’d help with a radiator and I bought their fans to go along with it.
I contemplated moving the steering rack but decided to drop the cradle to allow access to the harmonic balancer. I decided to do this because I was learning about some issues including the impossible-to-reach bleeder on the slave cylinder and figured if I dropped the cradle, maybe I could lower the motor enough to swap it out for a remote bleeder.
Then I got word from a friend who has connections that if I wanted a clutch, Centerforce would be interested in helping with the build.
So my hand was forced and and I decided to pull the motor.
Yeah, it sure isn’t a quick pull that’s for sure.
I just do all my own work so i couldn’t get it out and in very quickly. 30 minutes before the kids wake up, 15 maybe during naps, another 15 at night..... slowly but surely, it came out!
the first thing I did (after dropping the heads off) was to replace the slave cylinder and throwout bearing. I bought a gm replacement but in looking around, I learned about the plastic bushing/retainer being problematic and that a few companies offered a metal replacement. Quartermaster supplied one of their retainers and it went on pretty easily.
There are videos and posts on swapping them and it’s pretty easy. I’d suggest popping the retaining ring off by putting a screwdriver through the tube from the backside of the cylinder and hitting the clip forward.
Also, keep pressure on the bellows and the spring inside while swapping the retainers. The spring can unseat the bellows if you let it go and getting it all together after is a unnecessary little challenge.
To remove the original, you have to pull the bellhousing off of the torque tube. Even with the motor out and the tube lowered a bit, this wasn’t super easy. Not the most difficult but still challenging.
Also, be very careful when attaching the slave cylinder line to the fitting on the master’s line. I thought I had it but after reading about people having difficulty, I double checked and sure enough: mine had not snapped together. I had good access with the motor out and could not get it so I swapped the piece on the end off of the new with the piece off of the old. The new one had an oblong shape to it and was likely why it wasn’t connecting. The old one snapped into place easily.
I bit the bullet and bought a nice remote bleeder - as suggested, it is a good addition and now was the time to do it.
I wish i had done the rear main seal but it isn’t leaking and I figured why fix what ain’t broke. Maybe not the best plan, but so far so good.
While it was out I figured it would be foolish not to pull the pan and fit some sort of baffle. So improved racing helped out a bit with the pan baffle and their crank scraper and windage tray.
i put a new harmonic balancer on and pinned it with a kit from lsxinnovations. They sent me one to test on the ls7 and the jig worked but the bolt was too short. They will get a proper kit together but I just used the stud I made to install the balancer to hold it on.
I took the original balancer bolt (which is a one-time tty bolt), cut the head off and welded a threaded high-strength stud to the end to make my own installation tool.
I had to seal up the keyway on the new balancer to keep it from leaking, and it seems to be holding up.
I got a new Centerforce clutch and aluminum flywheel and it all went together really easily, as expected.
Getting the motor back in and lined up wasn’t fun but it eventually went together well. I found that disconnecting the power steering pump reservoir and one of the cooler lines made it easy to get the pump in place on the bracket. And tightening the bracket was enormously easier as well, compared to taking it off. I notched the mounting tab for the reservoir so it just slides off of the bolt that had previously entrapped it.
I got a new, unused water pump from the forum as well as a new silicone hose kit. Both were the newer style and went together with no problem.
I also talked to dewitts and they supplied a radiator and I opted to get their fans as well. I don’t think there is an easy way to get that in but it certainly wasn’t any more difficult than stock.
I am very happy with their fit and finish - a fantastic product.
It fired right up and after after a few seconds of a noisy lifter or two, settled right in. The only issue I had was with my starter: It started the car fine the first and second time after getting it together. The third time, it made a horrible crunching noise and then just spun.
I figured i lost a starter but couldnt couldn’t figure out why. I started to pull the starter and saw something amiss.
It looked like the starter’s guts were being spit out. Turns out I discovered where lost socks go: they find their way into wayward starters apparently.
Once I pulled out what was left of the sock and blew out the remnants, it starts up as it should.
I am currently at izzy performance in Carson awaiting the magic of their tuner, Tom. I just want a reliable motor, numbers are not important to me.
Thanks for the heads up - I’ll definitely keep an eye on temps and those fans. They are such a pain to get in and out that I will just leave them for now but I’ll keep an eye out for any issue.
And i hope to have better luck with the competition clutch. Hopefully your problems were anomalies
I had an intermittent cam position sensor code throwing during the dyno test and after buying a new $50 sensor and breaking the tab on the old one getting it out, I discovered that while the sensor was plugged in well, the pigtail that connects the sensor to the wiring harness had come loose at the harness.
at least it was a pretty easy fix and I shouldn’t have to worry about that sensor for another 80k miles!
I had an intermittent cam position sensor code throwing during the dyno test and after buying a new $50 sensor and breaking the tab on the old one getting it out, I discovered that while the sensor was plugged in well, the pigtail that connects the sensor to the wiring harness had come loose at the harness.
at least it was a pretty easy fix and I shouldn’t have to worry about that sensor for another 80k miles!
Ain't that the chitz! Anyone who's worked on just about anything has fixed something that wasn't broken. As you can attest, oft times, the correct fix is cheaper than the "first fix". At that point, all you can hang your hat on is that the thing you fixed, that wasn't broken, won't soon break. Shoot.....
05-23-2018, 09:57 PM
Taking a bone stock C6 Z06 and trying to make it faster
