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Sure, I can, but I have Girodisc rotors on all corners. I suppose it'd mean the ducting+directional rotors, if fronts are significantly cooler.
I think I agree on the gearing. There are quite a few corners at my local tracks where I made the same sector time by running through it at 3rd, or by using 2nd with hitting/coasting at redline for a part of it (hard to shift during these sweepers). I think the Z51 ratios could work much better with a 7-7.5K RPM redline.
Sure, I can, but I have Girodisc rotors on all corners. I suppose it'd mean the ducting, of fronts are sufficient l significantly cooler
I think I agree on the gearing. There are quite a few corners at my local tracks where I made the same sector time by running through it at 3rd, or by using 2nd with hitting/coasting at redline for a part of it (hard to shift during these sweepers). I think the Z51 ratios could work much better with a 7-7.5K RPM redline.
That's my plan for the 427 GS project, replace the gearsets with the Z06 gears and have an RPM build on the trans. I really like the closer ratios of the Z06/ZR1 but even then I could use some extra revs in 2/3/4. Luckily the 7000 RPM redline will fix that. Here is a quick analysis I did of the gear rations.
The gear ratios you have in the table under GS are the non-Z51 (standard Stingray) gear ratios. They actually aren’t bad, especially if you had a higher redline.
The GS has the Z51 ratios:
1. 2.97
2. 2.07
3. 1.43
4. 1.00
5. .71
6. .57
7. .48
2nd is too short, the jump from 3rd to 4th is very long and 5th is way too long to be useful.
Originally Posted by Poor-sha
That's my plan for the 427 GS project, replace the gearsets with the Z06 gears and have an RPM build on the trans. I really like the closer ratios of the Z06/ZR1 but even then I could use some extra revs in 2/3/4. Luckily the 7000 RPM redline will fix that. Here is a quick analysis I did of the gear rations.
Indeed, Z51/GS ratios are actually good, but they'd be a better match with a higher redline. This was one of the things I miss from my C6 Z06. LS7 is a beautiful engine for track duty (if it doesn't fail).
That said, since LT4 has so much torque, it might just "pull off" and make a good use of those taller initial gears. I'll hopefully have the sector data to compare once I finally give it a shot.
Indeed, Z51/GS ratios are actually good, but they'd be a better match with a higher redline. This was one of the things I miss from my C6 Z06. LS7 is a beautiful engine for track duty (if it doesn't fail).
That said, since LT4 has so much torque, it might just "pull off" and make a good use of those taller initial gears. I'll hopefully have the sector data to compare once I finally give it a shot.
I also traded in my GS (LT1) for a '19 Z06, about a month ago. Had a nice 650 mile ride home to get a head start on my break-miles. Since then I haven't been to the track, but I have done a little track inspired testing. I'll start a thread on this when I have some useful data, but there's a pic below. I can tell you that I'm thrilled with the gears and the power. 3rd to 5th are very close together, never getting below 5400 RPM if shifting at redline. Or the gearing should allow us to use the wide ranging torque and holding a higher gear to save a shift. Absolutely thrilled.
Can you provide more info on the power steering cooler? Is that a GM piece, aftermarket, or something you concocted?
Thanks.
There's a TSB on this, and the dealers can do this for free for you, if you end up getting power steering overheating warning at the track, and lose power steering boost. http://www.corvetteactioncenter.com/...2016-1271.html
I've already done this for my '16 Z51 at the time, so I just carried over : ) Admittedly, their fabrication looks better than mine.
Looked at the link and the minute I saw the duct I knew right away it was a brake duct. Looks like a fairly simple install. Probably do it myself if I ever get the message. One less visit to the dealer is always good in my book.
I've been talking to the track day organizers (Tom@ Turn2 for Ridge Motorsports Park, and Oregon Raceway Club), and looks like there might soon be winter track days for winter. This means I'd better start working hard on hitting 1500 miles; I'm currently at ~700 miles.
To do list before the first event:
Alignment: I'm trying to get it done ASAP; waiting on my favorite technician to come back from vacation. I had great results with -3/7.5/0 front, -2/0.8/0.05 rear (camber, caster, toe; all in degrees).
The taller drive height will make it harder to hit these numbers, especially at the front. I think -2.5 would normally be about what you can get.
Washers, or lack thereof: In anticipation, as I've mentioned, I've replaced the final set of upper control arm washers with much thinner shims. I'm hoping to gain 0.4 degrees or so of camber with this change, which would bring it back to max -3 degrees range. Looking forward to seeing if it worked.
Adjustable toe link: I've had a long debate re: using the adjustable toe links at the rear. After all, replacing that last washer may just do the trick and let me get to -2 camber, along with 0.8 degrees of caster. The reason for my hesitation is the fact that it changes the toe curve. I've ultimately decided to use it, since I've read in drag racing threads that these toe links also prevent the toe loss that happens during heavy load due to soft bushings on the OEM links. I'm sure this would also be great for road course track use, giving you more traction and thrust, exiting corners.
Switch to the race pads and final bleed (always a good idea to bleed again after a while, after a caliper swap).
Switch to B.C. Forged wheels and track tires: I currently have 315/335 R888Rs on the wheels. I really would like to use the R7s that we can now source even cheaper at Trackdaytire.com with the 10% coupon, but I'll need to get these finished, first. Speaking of which, I would like to try R888Rs at the street in cold weather, too. My brother hated PSS ZP tires on a friend's '17 GS, and thinks I can do much better. Both R888Rs and NT01s provide great traction almost instantly (before the warm-up), so I'm hopeful they might work!
Harness bar and race harness: Finally, I'll install the harness bar and Schroth Profi II ASM race harness. The OEM competition seats come with much stiffer foams. It's all good in terms of support, but it also makes me sit even higher in the car! I've not changed the bottom foam back when I converted my GT seats on my Z51 for this very reason. We'll see if it works out once I install the harness.
Looked at the link and the minute I saw the duct I knew right away it was a brake duct. Looks like a fairly simple install. Probably do it myself if I ever get the message. One less visit to the dealer is always good in my book.
I have all the parts in my garage, I just need to build it. I'm also going to design some type of cap for street driving, so I don't have to take that thing on and off all the time (to keep my engine compartment clean/free of excess water).
Last edited by clarkkent06; 01-04-2019 at 06:16 PM.
I have all the parts in my garage, I just need to build it. I'm also going to design some type of cap for street driving, so I don't have to take that thing on and off all the time (to keep my engine compartment clean/free of excess water).
Yeah, I'd not worry about water at all. There are too many holes to plug in there; water will find its way in. Just make sure you take the SUV for your next off-road outing : )
If anything, it'll keep the engine bay (slightly) cleaner. I thought the TSB said something about removing it for street use. edit: it does. Whatever a cap is no big deal, I'm doing it anyways
Last edited by clarkkent06; 01-04-2019 at 07:51 PM.
If anything, it'll keep the engine bay (slightly) cleaner. I thought the TSB said something about removing it for street use. edit: it does. Whatever a cap is no big deal, I'm doing it anyways
every add on piece will say that because they haven't gone through all their weather tests in case some idiot someone breaks their car and tries to blame gm for it.
Great to read through and loved looking at all the pictures! You don’t do downtime well I can tell lots of different cars and in depth posts give it away haha!
I would just add that when you dyno that you do a couple stock pulls and a couple BMS filter pulls. It just doesn’t work well with dynos and testing given condition differences and small vehicle differences to hope for a stock baseline from someone else and have that be an example for power gain.
Dyno results bone stock engine LT1 vs. w/ BMS drop-in filter
I sourced this filter a while ago, and I was waiting for this day to install it for more accurate before/after dyno results.
Setup:
Bone stock engine
46 lbs rear tires/wheels (vs. ~ 60 lbs stock tires/wheels). Z06 rear brakes w/ Girodisc 2-piece are also ~ 1.5 lbs lighter than stock Z51. Light rotating assembly might have increases the whp readings a bit.
26.1" diameter tires vs. 26.5" stock, so the gearing was 1.5% shorter than stock. In my experience, taller gearing usually generates better results due to increasing the load, but 1.5% in either direction is negligible.
Why BMS: For those who don't know, BMS filter widens the opening (mouth) of the air filter, which improves the air flow by MAF. Since MAF is tuned to accommodate the turbulence caused by restrictions of OEM filter's opening, it ends up undermining the actual air flow. Long story short, this filter causes the engine to run ~8% leaner per those who reported. Since the engine is tuned 10-13% too rich from the factory (per others' opinion), it returns nice gains without introducing knocks (I did not see any puffs or jitters during any pull).
Key for pulls (look-up this list to reference pull #s in charts):
Stock 3rd gear
Stock 4th gear
Stock 5th gear --> Hit speed governor at 187 MPH
BMS 3rd gear --> Right after ECU reset. Highest 3rd reading, and should be discarded since engine did not have a chance to start pulling timing per new flow and A/F ratio. Pull #6 is a better representation of 3rd gear with BMS.
BMS 4th gear
BMS 3rd gear
3rd gear pulls. Disregard pull #4 as explained above. There are very impressive gains in mid-range. They all meet together in the end, so the overall HP increase is almost negligible at peak, but from 4K RPM to 6K RPM, if ECU retains this in future, I'll enjoy around 390 whp, while the stock filter provided around 360 whp; I'll take it : )
4th gear pulls. Similar to 3rd, but the gains are much lower (and much closer to what is expected): ~+8.5 whp and wtq. The gap seems to widen to 10+ as we get closer to redline, and didn't fall off as fast right at the redline.
I am not sure why the gain is very good in 3rd gear, but it will definitely help at the track. Most of my track driving is from 2nd gear to 4th gear, and 3rd gear is likely the most used among them, so these gains might indeed help.
The change did not cause any check engine lights, etc.
It also did not seem to cause any knock (no puffs). Due to the exhaust design, the dyno shop was not comfortable with installing sniffer, so I don't have AFRs. Needless to say, though, they got leaner.
This time around, I'd like to have driven quite a bit after the filter install to make sure any learning would have happened. As such, I actually need to get it dynoed on two different days, but that's too much of a hassle that I don't have time for. One mitigation is that this dyno has been very consistent (I've dynoed many cars, there), and I'm hoping he'll have enough data for analysis.
12-30-2018, 08:15 PM
