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Thread: Gen V Upgrades choosing a cam

  1. #1

    Gen V Upgrades choosing a cam

    I have a GMC Denali Truck 2017 with 6.2L 8L90E
    2.9L Whipple 3.75 pulley 12~lbs boost
    Stainless works headers
    True Dual Exhaust
    X Pipe
    Venom 250 Mufflers

    I have ordered a Circle D 258mm Pro Series 2800-3000 Stall
    Rep said it would drive pretty much stock if I stayed out of the gas. Would not need any extra cooling and would maintain if not exceed the stock tow capabilities.

    What I'm having trouble with is deciding on a Cam
    I like some chop to my cammed Vehicles. But this is a truck and I don't want to lose all of my low end.

    The factory cam is
    200/207 .551/.524 116.5 (DOD/AFM)

    I was looking at the BTR Stage 1 Blower cam
    225/240 .64x/.62X 116+6

    So I called BTR and had them put together a couple of cam specs for me.
    The first cam spec
    215/240 .630/.648 116.5 +3.5 (Noticeable Idle)

    221/247 .638/.645 117 +5 (Rougher Idle)

    I really dont know what the sweep difference in the torque and HP curves differ. My rep says he would go with the first cam but I think I would like the second one thats slightly more aggressive. I feel that BTR knows there stuff. But I crave a bit of the rump at idle.

    Opinions?

  2. #2


    You can get more chop by doing some changes to the idle table that cause timing to swing a bit wildley causing a rougher idle exemplifying the cam characteristics.

    The second cam is adding 6 degrees duration on the intake and 7 on the exhaust.

    Calculations say the stock cam has -29.50 of overlap
    Stage 1 BTR blower cam .5
    Custom Cam 1 -5.50
    Custom Cam 2 0

    Would be interesting to see what the dyno differences are between Stock, Cam 1 and 2.

  3. #3
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    The Stage 1 blower cam will work nicely for your application. It'll still maintain good torque at the flash point of your converter to get that heavy truck moving nicely.

  4. #4
    Senior Tuner SultanHassanMasTuning's Avatar
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    dont forget to look into add the fuel lope. but as mentioned manipulating your idle is easy
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  5. #5
    Quote Originally Posted by SultanHassanMasTuning View Post
    dont forget to look into add the fuel lope. but as mentioned manipulating your idle is easy
    38% fuel lobe on the custom cams.

  6. #6
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    All cams are blower cams. Spend some time on Richard Holdener's channel on YT. This should expand your pool of cams to choose from. Sure seems like a lot of split, maybe it's because the exhaust side of the heads flow so poorly?

  7. #7
    Quote Originally Posted by kevin87turbot View Post
    The Stage 1 blower cam will work nicely for your application. It'll still maintain good torque at the flash point of your converter to get that heavy truck moving nicely.
    I think the stage 1 blower cam is an all around blower cam. Centrifugal, Roots and Twin screw.

    I would hope the custom cams are optimized for Twin Screw as thats what im running and they know that.

    I would also believe its not as optimized for my setup as the heads are different on the trucks from what I understand and that cam is commonly used in Vetts with factory blowers.

    Quote Originally Posted by lucas287 View Post
    All cams are blower cams. Spend some time on Richard Holdener's channel on YT. This should expand your pool of cams to choose from. Sure seems like a lot of split, maybe it's because the exhaust side of the heads flow so poorly?
    I too thought that exhaust duration was Narrly too and I assumed the same thing. I have Stainless works headers and exhaust so the exhaust itself shouldn't be restrictive.

    I have been watching Richard Holdener and his results seem to agree that smaller cams (larger than stock) Tend to do better all the way around even in blown applications.
    Last edited by HellKnightHicks; 04-12-2021 at 12:19 PM.

  8. #8
    Cam numbers

  9. #9
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    The LT1/L86 heads have a strange exhaust port orientation. This is a good nitty-gritty article on it! https://www.onallcylinders.com/2018/...m-gen-v-heads/

    If it were my truck, I'd go for a larger cam too for many reasons:

    *we don't have vacuum brakes any more
    *the whipple will help offset any part throttle torque loss
    *having less dynamic compression down low is a good thing in a truck application - to a certain extent. Think high load-low rpm scenarios where KR is a real concern.
    *real, natural lope instead of fudging the tune
    *absolute SCREAMING top end!

    I just don't know if that's the right cam. Maybe there's something about BTR grinds that I'm not aware of, but that seems like a cam that will be very hard on springs too
    Last edited by lucas287; 04-12-2021 at 12:39 PM.

  10. #10
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    Quote Originally Posted by HellKnightHicks View Post
    heads are different on the trucks

    I have been watching Richard Holdener and his results seem to agree that smaller cams (larger than stock) Tend to do better all the way around even in blown applications.
    Same heads on the LT1

    In a NA, street car application I'd always suggest being conservative with a cam. Part-throttle torque production is king here. But, you're blown and with bolt-ons. Less part-throttle torque (bigger cam, in general) would probably make that truck more driveable honestly. My truck is just e85 converted with a Corsa and I can't hook up in 2wd any any speed under 25 MPH. Can't imagine with your setup lol

  11. #11
    Quote Originally Posted by lucas287 View Post
    Same heads on the LT1

    In a NA, street car application I'd always suggest being conservative with a cam. Part-throttle torque production is king here. But, you're blown and with bolt-ons. Less part-throttle torque (bigger cam, in general) would probably make that truck more driveable honestly. My truck is just e85 converted with a Corsa and I can't hook up in 2wd any any speed under 25 MPH. Can't imagine with your setup lol
    The truck is a crew cab. I think my tune is trash. I don't feel that it has all that much power really. But I drive a 2012 camaro with supercharger cam and full exhaust. its stupid fast in my opinion runs around 600hp.

    Since I plan to use it as a truck and tow with it occasionally that may be the reason for the lower cam specs. But honestly I wont tow with it very often. The 3000 Stall worries me a bit about how it will effect normal driving.

    I've been partial to the second cam specs myself. BTR rep says it will hurt the streetability of the truck. But I cant get any details out of him about how it will effect the power curve down low. I would think regardless with the cam change alone I would be making more than stock down low even before the super charger kicks in.
    Last edited by HellKnightHicks; 04-15-2021 at 08:25 AM.

  12. #12
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    Quote Originally Posted by HellKnightHicks View Post
    The 3000 Stall worries me a bit about how it will effect normal driving.

    I've been partial to the second cam specs myself. BTR rep says it will hurt the streetability of the truck. But I cant get any details out of him about how it will effect the power curve down low. I would think regardless with the cam change alone I would be making more than stock down low even before the super charger kicks in.
    More input torque can actually increase stall speed above what Circle D says, so maybe ask them what it would be with an extra 100 lb ft down low. Too bad you have a '17 because with a good TC strategy, you could indeed make it very driveable. I had a 3500 Edge TC in a Mustang 4.6 2V, mind you it was way overcammed, and the damn thing was a turd down low. But it sure was snappy and 7000 RPM shifts it would only drop about 1500 RPM.

    Either one of those cams will have quite an effect on low-end, part throttle torque in a NA-application. I just don't see how a blower wouldn't MORE than offset those losses. The cam will dynamically lower compression, but the blower will increase it.

  13. #13
    Quote Originally Posted by lucas287 View Post
    Same heads on the LT1

    In a NA, street car application I'd always suggest being conservative with a cam. Part-throttle torque production is king here. But, you're blown and with bolt-ons. Less part-throttle torque (bigger cam, in general) would probably make that truck more driveable honestly. My truck is just e85 converted with a Corsa and I can't hook up in 2wd any any speed under 25 MPH. Can't imagine with your setup lol
    I believe the direct injected version has different ports as discribed in that edilbrock artical.

    After seeing the total failure of Edlebrocks Inline 6 aluminum cylinder head. From thin walls, casting issues and to 0 performance gains over a stock ported cylinder head. I dunno about there opinions.

    Quote Originally Posted by lucas287 View Post
    More input torque can actually increase stall speed above what Circle D says, so maybe ask them what it would be with an extra 100 lb ft down low. Too bad you have a '17 because with a good TC strategy, you could indeed make it very driveable. I had a 3500 Edge TC in a Mustang 4.6 2V, mind you it was way overcammed, and the damn thing was a turd down low. But it sure was snappy and 7000 RPM shifts it would only drop about 1500 RPM.

    Either one of those cams will have quite an effect on low-end, part throttle torque in a NA-application. I just don't see how a blower wouldn't MORE than offset those losses. The cam will dynamically lower compression, but the blower will increase it.
    The stall is actually a 2800-3000.

    Why would a 17 not be able to have a good TC schedule? My trans controller is unlocked?

    I still don't have a final decision on the cam lol its down to 2. I would generally go bigger but its a truck.

  14. #14
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    Quote Originally Posted by HellKnightHicks View Post

    Why would a 17 not be able to have a good TC schedule? My trans controller is unlocked?
    Whoops! Just assumed it was locked because of the ridiculous cost. Then I see no downside to a looser stall!

  15. #15
    Quote Originally Posted by lucas287 View Post
    Whoops! Just assumed it was locked because of the ridiculous cost. Then I see no downside to a looser stall!
    I looked at the AT4's before buying this truck and said no way to that.

    I finally figured out what I was doing wrong with BlueCats Trans tuner. I think I have a good trans tables now.

    Waiting for circle D to finish building my Tq converter before I put the order in for the parts from BTR.

    I like the CHE brass bearings but BTR offers the captured roller bearings. BTR says there both good.

    Though I may have to wait a bit for finances to replenish.
    Last edited by HellKnightHicks; 04-23-2021 at 12:42 AM.

  16. #16
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    Quote Originally Posted by HellKnightHicks View Post
    I looked at the AT4's before buying this truck and said no way to that.

    I finally figured out what I was doing wrong with BlueCats Trans tuner. I think I have a good trans tables now.

    Waiting for circle D to finish building my Tq converter before I put the order in for the parts from BTR.

    I like the CHE brass bearings but BTR offers the captured roller bearings. BTR says there both good.

    Though I may have to wait a bit for finances to replenish.
    Look at the cam this guy is using over at pt.net, stay tuned to see what numbers he gets!

    https://www.performancetrucks.net/fo...verado-558524/

  17. #17
    Quote Originally Posted by lucas287 View Post
    Same heads on the LT1

    In a NA, street car application I'd always suggest being conservative with a cam. Part-throttle torque production is king here. But, you're blown and with bolt-ons. Less part-throttle torque (bigger cam, in general) would probably make that truck more driveable honestly. My truck is just e85 converted with a Corsa and I can't hook up in 2wd any any speed under 25 MPH. Can't imagine with your setup lol
    I see what your saying now. Finally got a good trans tune on my setup as well as a stabilitrack disable switch. It definitely wants to spin the tires as it is right now. Cant belive how much stabilitrack was holding everything back.

    Before it shifted pretty poorly all over the place supercharger would just be hitting and then a gear change would happen.

  18. #18
    Ordered my Cam today.

    Its based on the PDS line of BTR cams with some changes specifically for my application.
    223/247 638/.645 117 +5.5

    I like these cam specs quite a bit better than the others.

    Its basically a modified version of the BTR PDS Stage 3 Cam
    223/246 .610/.600 117 +6

    Gotta call CHE to get my trunnions on order. BTR has some 40+ still on back order. CHE said they could ship within a couple weeks.

    Custom cam will be in in a couple of weeks as well.

  19. #19
    Senior Tuner Ben Charles's Avatar
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    Glad you have a converter with that cam!

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  20. #20
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    If your doing the install your self make sure you measure for the lash cap on the fuel lobe.