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Funny, I suspected that. M in the same thought process as you are. Very similar data from COTA. I thought it was something else. When i looked at the data the car was definitely slower every where as laps progressed.
Yeah, there are enough straights at CMP where it becomes very evident. Its hard to tell in the seat of the pants that you are .7 seconds a lap slower but when you start looking at the data its pretty eye opening.
Is it a heat issue, or something that could be combated with higher-octane race fuel? Possibly both...
If heat, seems like ceramic coating and wrapping headers/cats would be a good place to start, along with dumping a bottle of Redline WaterWetter into the cooling system (which I've already done). The RLWW made a huge impact in my 2014 C7 Z51 which ran notoriously hot from the factory.
Is it a heat issue, or something that could be combated with higher-octane race fuel? Possibly both...
If heat, seems like ceramic coating and wrapping headers/cats would be a good place to start, along with dumping a bottle of Redline WaterWetter into the cooling system (which I've already done). The RLWW made a huge impact in my 2014 C7 Z51 which ran notoriously hot from the factory.
I have header blankets, and my exhaust wrapped, and blankets on my cats as well. The C8 has great cooling from the factory when it comes to its coolant system, that system is quite over engineered when you look at it compared to the C7. I want to actually log the situation on track to show everyone what it is, and then share a solution. Hopefully can do this in the next month.
J5 I don't understand the graph you provided in regards to data points of engine performance, I could use a little help there. I have done quite a bit of logging myself but at the racetrack, my quickest passes have come with a generous cooldown in between. I have hot lapped passes also and datalogged each one, I dont see much difference in engine performance even though my timeslips say I've run slower. I have a hunch the tcm is playing with clutch engagement as temps heat up but I cant log that to verify.
Just putting that out there to see if maybe their is something there that can be identified and remedied.
I'm not going to give the specifics because I'll attempt to address it and will post about the fix when I get it. The car has the ability to pull 15 degrees of timing, that's about 100hp....
And for those that dont think the car is pulling timing, here are 3 laps at CMP this weekend, Green = Lap 1 first line (flat line), Red Lap 2, Blue Lap 3. At a time trial you basically get 1 lap, you have no chance to set a 'good' lap on lap 2 or 3 because the car has pulled so much power out of it, yeah its still fun to drive but when you are going for that ultimate lap it sucks you only get one shot at it. I dont think these results are accurately mimicked on a dyno for multiple reasons.
What tires are you on? You sure they’re not falling off?
What tires are you on? You sure they’re not falling off?
Yes I'm sure the tires werent falling off on the 2nd lap. All indications are that the second lap is actually a better driven lap, most apex speeds are higher on the second lap, as you can see a little bit in those lines as the line dips slightly, and then trends back upwards on each straight.
We'll get it figured out.
Yes I'm sure the tires werent falling off on the 2nd lap. All indications are that the second lap is actually a better driven lap, most apex speeds are higher on the second lap, as you can see a little bit in those lines as the line dips slightly, and then trends back upwards on each straight.
We'll get it figured out.
I thought you ran Yoks and if ambient is hot then I’ve experienced the first lap being the fastest as I run time trials as well and pretty much experience it with all 200tw as they only have a small temperature window of optimum grip, being deeper treaded with grooves increases heat build up as the rubber squirms more. The 3rd lap is consistently slower as well, I thought the C8 was pretty proficient at cooling so can’t imagine ECT is fluctuating that much on 3 laps?
Dyno was completed with these mods added on: Current performance HP/TQ mods added are: Halltech Hornet Cold Air Intake 95mm Gwatney Manifold
95/100mm Soler LT5/ZR1 Throttle Body
Soler Throttle Controller
Fabspeed HJS 200 Cell Cats
Will be doing a comparison Dyno Friday now that the Lingenfelter pTR intake manifold has replaced the 95mm Gwatney intake manifold.
@ArizonaZ06 did you ever get those DYNO #'s after the pTR installation?
Current performance HP/TQ mods added are: Halltech Hornet Cold Air Intake 95mm Gwatney Manifold
95/100mm Soler LT5/ZR1 Throttle Body
Soler Throttle Controller
Fabspeed HJS 200 Cell Cats
RWHP 453.53
RWTQ 437.44 So with the above mods, you picked up about 20Hp. Have I got this right? Thanks.
Not at all. There is no way to know without a baseline.
His runs were done on a dynapak which is a hub dyno. You completely remove 40 plus pounds per corner in wherl and tire to dyno on that dyno. For this reason they read significantly higher than dynos like a dynojet.
Not at all. There is no way to know without a baseline.
His runs were done on a dynapak which is a hub dyno. You completely remove 40 plus pounds per corner in wherl and tire to dyno on that dyno. For this reason they read significantly higher than dynos like a dynojet.
I thought they could be calibrated to take that it into account?
I thought they could be calibrated to take that it into account?
Not necessarily. We routinely use them and theyre plus 10 percent compared to the champion racing big drum dynojet which reads the same as some mustangs (mustang dynos can read all over the place). Theyre 5 percent over dynojet small drums. Dyno dynamics will read upwards of 20 percent lower but those dynos notoriously read way low.
Dynos without baselines are useless. You can get a 30whp difference on the mustang accidentally just from calibration.
Then even if you baseline you need to datalog too. You can get a 50whp difference by not running the two sessions at different intake temps. If you trigger 1 singke degree on the other side of an iat temp safety the car can end up running on a intake temp safety timing map (it wint show timing retard it will just switch over to reduced timing map).
Aside from all that, yes the hub dyno dynapak tends to read quite high. But all dynos are calibrated differently. Heck the mustang dyno in Lexington we used to use read higher than any dynojet or other mustang we used. These are just generalities that the hub dynos read higher. In they do. But that one may not. There's zero information to gleen without a controlled conditions baseline. For all we know the car lost power with those mods or gained. No way to know.
Not necessarily. We routinely use them and theyre plus 10 percent compared to the champion racing big drum dynojet which reads the same as some mustangs (mustang dynos can read all over the place). Theyre 5 percent over dynojet small drums. Dyno dynamics will read upwards of 20 percent lower but those dynos notoriously read way low.
Dynos without baselines are useless. You can get a 30whp difference on the mustang accidentally just from calibration.
Then even if you baseline you need to datalog too. You can get a 50whp difference by not running the two sessions at different intake temps. If you trigger 1 singke degree on the other side of an iat temp safety the car can end up running on a intake temp safety timing map (it wint show timing retard it will just switch over to reduced timing map).
Aside from all that, yes the hub dyno dynapak tends to read quite high. But all dynos are calibrated differently. Heck the mustang dyno in Lexington we used to use read higher than any dynojet or other mustang we used. These are just generalities that the hub dynos read higher. In they do. But that one may not. There's zero information to gleen without a controlled conditions baseline. For all we know the car lost power with those mods or gained. No way to know.
I agree dyno is a tuning tool, so need a baseline and hard to compare numbers from different ones. I understand all the tricks that can be played, but don’t have any experience with this style. The only shop that I know of locally with one says it’s pretty close to their dyno jet, though they probably have it calibrated correctly.
I am going to Dyno my C8 with some other guys on Saturday. We just want to baseline our cars and have a fun day out.
Does it matter what mode I am in?
Is it better in tour, sport...drive or manual...NPP open or shut or doesn't it matter?
I am going to Dyno my C8 with some other guys on Saturday. We just want to baseline our cars and have a fun day out.
Does it matter what mode I am in?
Is it better in tour, sport...drive or manual...NPP open or shut or doesn't it matter?
Track mode, manual, IIRC 4th or whatever is closest to 1 to 1. Track mode should put NPP in open position, plus being at WOT should also make it open in other modes. It needs blowers directed at side intakes, and front.
We’ve tried everything and car keeps going into first gear. Won’t stay in fourth on rev.
is the M lit up on the gear switch. It will start in first, but keep switching up gears until 4th while keeping the revs up above say 1500 rpm. It will not let you lug or over-rev when selecting gears. It will not start from a start except in 1st.
