12-29-2023, 06:37 PM | #1 |
Drives: Chevrolet Camaro Z28 (2015) Join Date: Feb 2023
Location: Washington state
Posts: 124
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Making LS7 more reliable and faster ? I hope so
Hey folks,
starting this thread to share my journey with LS7 mods. Disclaimer: I AM AGAINST ALL MODS on a well engineered car. I use my Z/28 on the racetrack only (and to drive to/from there) and after reading here in the forum and talking with other LS7 owners (although Z06 vette ones, which is different vintage of LS7) I got quite scared about head problems. Btw It was also surprising to learn that there are rods problems too , but I am not willing to think about opening the block. Anyway, in order to mitigate the risk of valve issues I decided to buy heads. When I got the car, I also got some performance pieces with it (but uninstalled): a TSP BFD cam with all necessary accessories to install (pushrods, all bolts, gaskets...) here's the cam specs: https://imgur.com/JCy2ZfZ I was looking around for heads, given that I will replace them and I have a cam already, it makes sense to install everything at once, right? I'm not looking for horsepower but I suspect that this cam will still give me plenty. I've looked to various heads and I was interested in the trickflow ones but then on black friday MAST motorsport made a 50% discount on the "factory" heads. https://www.mastmotorsports.com/coll...-mast-head-305 I've purchased it with:
here's the cam specs: Dimensional Specs Bore Size: 4.125 (+) Weight: 28 lbs. Intake Valve Size: 2.250" Exhaust Valve Size: 1.600" Valve Stem Diameter: 5/16" Valve Length: 5.450" Valve Angle: 12° Valve Spring Pocket Diameter: 1.580" Valve Spring Install Height: 1.800" Head Stud Size: .4375" Valve Guide OD: .502" Valve Job Type: As Cast Air Flow & Performance Criteria Intake Max. Flow: 375 CFM @ 1.000" Exhaust Max. Flow: 192 CFM @ 1.000" Intake Average Flow: 288 CFM Exhaust Average Flow: 165 CFM Intake Seat Material: High Chrome Alloy Steel Intake Port Volume: 292cc Exhaust Port Volume: 104cc Standard Chamber Volume: 71cc Port Type: As Cast Materials Cylinder Head Material: A356-T6 Aluminum Intake Valve Seat Material: High Chrome Alloy Steel Exhaust Valve Seat Material: High Chrome Alloy Steel Deck Thickness: .750" Rocker Stand Type: Mast Billet Rocker Arm Type: OE LS7 1.8 or Aftermarket Guide Material: Bronze General Rocker Stand Type: Mast Billet Rocker Stands Included: Yes Rocker Stand Dowels Included: Yes Uses Stock Rocker Bolts: No Rocker Bolts Included: No Rocker Arm Type: OE LS7 1.8 or Aftermarket Head Bolt QTY: 6 Bolt Style Valve Cover Rail Height: + ½ inch Can use OE Valve Cover: Yes the interesting part of the heads is the smaller valve angle compared to the stock one and the fact that they flow quite well. I'm waiting for headers, I didn't buy a 102mm Throttle body and intake as I've read various VERY contrasting opinions about it. I plan to dyno before and after, I'll post here to keep everyone updated
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2015 Red Z/28. Seattle area |
12-31-2023, 06:40 AM | #2 |
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Drives: 2015 Camaro 2LS, 2015 Camaro Z/28 Join Date: Nov 2019
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Wow, that is a pretty stout cam! I'd be a bit apprehensive about that much lift, valve train stress and longevity but I guess you're going for MAX N/A power. Can't wait to see some dyno and track results.
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2LS: a TREMENDOUS machine. Z/28: it's a BIT MORE POWERFUL, of course.
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12-31-2023, 12:52 PM | #3 | |
Drives: Chevrolet Camaro Z28 (2015) Join Date: Feb 2023
Location: Washington state
Posts: 124
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here's an interesting YT video about various LS7 heads , how they compare and how much CFM (flow rate) influences power output.
A bit on the nerdy side for most of us, but there's a gold mine of information here for those who want to learn.
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2015 Red Z/28. Seattle area |
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01-01-2024, 11:15 PM | #4 |
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Drives: 2015 Camaro 2LS, 2015 Camaro Z/28 Join Date: Nov 2019
Location: Mesa, Az
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That's a good vid. Wish they included Katech. In the back of my mind I fantasize about Katech heads, the LS7 570 HP cam, Caddy lifters, Kooks or ARH headers, cat delete and a good tune. Then I get in the car and drive it and say "damn, this thing runs SO good as it is". That makes it difficult for me to crack into it AND I've already got a high maintenance LS3 powered C5 Z06 for track duty. I don't have the time and/or patience for another project vehicle.
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2LS: a TREMENDOUS machine. Z/28: it's a BIT MORE POWERFUL, of course.
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01-02-2024, 05:38 AM | #5 |
Drives: 2012 Chevrolet Camaro l99 Join Date: Aug 2020
Location: Austin, TX
Posts: 2,189
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Man that's a huge cam! Can't wait to see the results.
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DSS FX Forged Pistons, Eagle ESP L19 Forged Rods, ARP Head and Main Studs, TSP PRC 260 CNC Ported Heads milled .030, Cometic .040 Head Gaskets, GPI SS3 VVT Camshaft, GM Performance Racing Lifters, CHE Trunnions , Molly Pushrods, Melling 10355HV Oil Pump, Cold Air Inductions CAI, Fast LSXR Intake Manifold, Nick Williams 103 TB, TSP 1 7/8" Longtubes with 3" TSP Exhaust, ZL1 Fuel Pump, Mishimoto Radiator, Mishimoto Oil Cooler, Tru Cool 40k Tranny Cooler, 3600 Circle D Converter, Fluid Dynamics Balancer
Build Thread https://www.camaro5.com/forums/showthread.php?t=609817 |
01-03-2024, 08:46 AM | #6 |
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What valves did you get? I hope not the stainless option - that's going to be a heavy valve with a fairly modest spring.
The cam is a really interesting grind - it's got a pretty early IVC and late EVO, which is going to keep it from wanting to do big rpm in a 427, but it has ridiculous amounts of overlap (34.5*) that's going to make a pretty focused powerband in the 5800-7000 range. Reading the advertisement, the marketing matches - it seems primarily focused on sounding super aggressive. No doubt it will achieve that with the overlap, but it's gonna drive very aggressive in a manual car. I would not expect to enjoy just cruising around under 2600rpm anywhere. I'm curious about your valve angle comment. Both the heads your bought and the factory LS7 cylinder head utilize a 12* valve angle, so not sure what you're seeing as different there. It'll be an interesting combination - let us know how it turns out!
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GPI Max Package 2.0: Brodix BR7 heads/GPI porting, MAX3 cam, ST2116LSR, BSR Max Lift rockers, LS7 LSXR with 103mm TB, Vararam OTR, Mcleod RXT, G-Force/Strange 9" IRS setup with 4.63 gear. 551whp, 11.1@124mph.
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01-03-2024, 09:48 PM | #7 | ||||
Drives: Chevrolet Camaro Z28 (2015) Join Date: Feb 2023
Location: Washington state
Posts: 124
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the titanium valves were waaaaaay too expensive. Also, consider that the TSP kit came from an "insider" and they ok perfectly ok (from a reliability perspective too) to install it on standard heads+valves+valvesprings. Quote:
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Status update: 1/ I've inspected the heads and one of two seems to have a bit too many "Flaws" so I've reached out to MAST to get an explanation and potentially a substitution. The other head is perfect. 2/ the shop that will assemble everything recommended to not use the TSP head bolts (one time bolts) but to get some ARP ones: "the ARP bolts are a hardened bolt with a recommend torque spec so we can get equal torque on all the bolts". I don't have any experience with either but what they explained to me about the head bolts made sense. I plan to take their advice.
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2015 Red Z/28. Seattle area |
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01-04-2024, 02:31 AM | #8 |
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Drives: 2015 Camaro 2LS, 2015 Camaro Z/28 Join Date: Nov 2019
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That cam seems like more of a profile suited for drag racing. 10 seconds at max power then coasting for a cool down. Not sure what tracks you'll be running but when I'm on track I spend a LOT of time in the 3-5000 RPM range in both 3rd and 4th gear and my Z06 and Z/28 have similar RPMs/MPH in those gears. You'll need to be fairly skilled to keep downshifting to keep the engine in that rather high power band. Oil temps will probably need to be addressed. I'm keeping in mind your quest for reliability. With all of those aftermarket variables in place that may prove to be difficult. A few years back I talked to a gent with a gutted and caged Z/28. Engine was stock. He told me the reason he could compete with the Vettes, BMWs and Porches was because of the brakes as he could carry so much more speed into the turns and brake much later then use the big 427 to pull away on the straights. The Z with the LS7 was designed and engineered fairly well. Just watch that Nurburgring video and ask yourself if major improvements are really necessary.
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2LS: a TREMENDOUS machine. Z/28: it's a BIT MORE POWERFUL, of course.
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01-04-2024, 06:44 AM | #9 | |||
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I'd have like to seen similar durations, but split a few degrees from the intake to the exhaust, and on a 112ish LSA. It would top end better (with some more spring and/or ligther valves), and pick up the mid-range a earlier, not to mention drive nicer. I do think a cam like you have has the potential to make a pretty good dyno number, I just worry about the narrowness of the power band. Definitely interested to see your results. It should sound monstrous! Quote:
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GPI Max Package 2.0: Brodix BR7 heads/GPI porting, MAX3 cam, ST2116LSR, BSR Max Lift rockers, LS7 LSXR with 103mm TB, Vararam OTR, Mcleod RXT, G-Force/Strange 9" IRS setup with 4.63 gear. 551whp, 11.1@124mph.
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01-04-2024, 08:24 PM | #10 | |||||||
Drives: Chevrolet Camaro Z28 (2015) Join Date: Feb 2023
Location: Washington state
Posts: 124
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my 2 main points are: 1/ will this engine have LESS torque in low end? I expect it to be quite similar, the main problem will be that the engine will "tend to stall" and the output will be irregular instead of smooth, but from a "time on track" perspective I'm not sure it will be much worse. 2/ I've checked some data and in the Seattle area there are 2 main tracks I'll use: The Ridge motorsport (fantastic) and Pacific Raceways. I've downloaded data from my telemetry and at the Ridge I spend ~13.18% of the lap time below 3000rpm. I expect similar data to be at Pacific Raceways (won't download telemetry do to the same analysis right now). These are 2 hairpins that are usually done in 2nd gear (or 3rd if you want to be REALLY low revs) and will probably call for a 1st gear if you are as slow as I am. For racetrack usage I think I should be ok... if it will become a hassle I will change cam in future. Quote:
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the only thing that comes to my mind is that if you do mistakes when torquing the OEM/TSP ones you cannot recover from mistake and have to replace them... while the ARP can be fixed But this is me speculating. I can't wait to share more info/data. For the time being I am manging a replacement of one of the heads and the rocker arms because the rocker arms are wrong (LS3 instead of LS7) and one of the heads have some imperfections that I don't want to deal with, so they are replacing it. My appointment to put everything together is on 3/12 , if the headers will come on time as well as the head replacement, we should be ok.
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2015 Red Z/28. Seattle area |
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01-05-2024, 08:26 AM | #11 | ||
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Average power is a critical piece to any sort of circle track or circuit car, where the engine has to operate over a sometimes fairly wide range - much wider than a drag engine that will have at most a 2400rpm window of operation for stick cars, and often under 1000rpm for really aggressive stall converter auto cars. This does make a case for cams that might actually sacrifice a bit of peak power from a broader curve that makes a better average. The "equalizer" in your case, to some extent, is the displacement, which will help torque production, and keep the RPM window modest. A FAST LSXR or MSD Atomic Airforce with a 103mm throttle body would compliment that setup well. adding power across the curve. I agree that the big TB on the stock intake likely is worth little to no power. I tested this on an LS3 - results here if you're interested:
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GPI Max Package 2.0: Brodix BR7 heads/GPI porting, MAX3 cam, ST2116LSR, BSR Max Lift rockers, LS7 LSXR with 103mm TB, Vararam OTR, Mcleod RXT, G-Force/Strange 9" IRS setup with 4.63 gear. 551whp, 11.1@124mph.
Got a question about a GPI product? Feel free to shoot me a message! |
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01-06-2024, 12:42 AM | #12 | ||
Drives: Chevrolet Camaro Z28 (2015) Join Date: Feb 2023
Location: Washington state
Posts: 124
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I always suspected that increasing TB size wouldn't provide significant benefits For the time being I am not going to replace intake manifold... maybe in future.
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2015 Red Z/28. Seattle area |
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01-06-2024, 01:18 AM | #13 | |
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Drives: 2015 Camaro 2LS, 2015 Camaro Z/28 Join Date: Nov 2019
Location: Mesa, Az
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Quote:
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2LS: a TREMENDOUS machine. Z/28: it's a BIT MORE POWERFUL, of course.
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01-06-2024, 01:09 PM | #14 | |
Drives: Chevrolet Camaro Z28 (2015) Join Date: Feb 2023
Location: Washington state
Posts: 124
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Quote:
I'm sure some guru in the forum will have the answer
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2015 Red Z/28. Seattle area |
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