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Assistance Please - Supercharger Build

33K views 26 replies 8 participants last post by  dcmx5 
#1 · (Edited)
I am just a few months away from the next steps in my build and am looking for specific guidance - Ideally from those with real world experience. I'm happy to hear from others without real world experience, but I would appreciate you detailing why you suggest what you suggest.

I have a 2017 Charger R/T with just over 50k miles. Current noteworthy mods are a 2.9L Whipple Stage 2 kit w/ CAI, 3.09 gears, Troy Ding TCM tune and Mike Doban OST ECM tune. Car is my daily driver and runs great, no issues.

I have a budget for the coming project - Let's call it $10k max. I am 100% committed to forging the rotating assembly, to include the pistons, rods, crank and all new premium bearings. At the time of writing this, I am also pretty committed to upgrading from the MSD boost-a-pump to a quality drop-in fuel pump rated for 700rwhp (the API or Pettys Garage offerings are in consideration as of now), 1050 injectors and a complete exhaust system (manifolds back). I am also leaning towards machining the block to a 392 during this time since I am getting a pretty reasonable estimate as to what that would cost.

With all of that said, and understanding I will also have to buy new tunes and other things that may come up... What stock components will kill this build if overlooked?

In other words, I understand it is beneficial to upgrade to a custom cam and ported heads, and if I had a bottomless budget I wouldn't hesitate to upgrade both, but since I don't.. Can I still enjoy the above modifications I'm committed to without upgrading either/both of these things? I understand the block will be open so now would be the time to do them, but a limited budget is a limited budget. I'm asking anyone offering input to account for that. I also appreciate that when I reach my 2020 goal of around ~650rwhp, my HP70 and stock R/T drivetrain may not love me. My hope, based on my research until this point, is that those components can hold strong and perform well until at least a year from now (when I get to my "phase 3" of this build).

If a new cam and upgraded heads are absolutely necessary, what are the most budget-friendly offerings you have seen that you could recommend?
 
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#2 ·
I am now just a few months away from the next steps in my build and am looking for specific guidance - Ideally from those with real world experience. I'm happy to hear from others without real world experience, but I would appreciate you detailing why you suggest what you suggest.

I have a 2017 Charger R/T with just over 50k miles. Current noteworthy mods are a 2.9L Whipple Stage kit w/ CAI, 3.09 gears, Troy Ding TCM tune and OST ECM tune. Car is my daily driver and runs great, no issues.

I have a budget for the coming project - Let's call it $10k max. I am 100% committed to forging the rotating assembly, to include the pistons, rods, crank and all new premium bearings. At the time of writing this, I am also pretty committed to upgrading from the MSD boost-a-pump to a quality drop-in fuel pump rated for 700rwhp (the API or Pettys Garage offerings are in consideration as of now), 1050 injectors and a complete exhaust system (manifolds back). I am also leaning towards machining the block to a 392 during this time since I am getting a pretty reasonable estimate as to what that would cost.

With all of that said, and understanding I will also have to buy new tunes and other things that may come up... What stock components will kill this build if overlooked?

In other words, I understand it is beneficial to upgrade to a custom cam and ported heads, and if I had a bottomless budget I wouldn't hesitate to upgrade both of these components, but since I don't.. Can I still enjoy the above modifications I'm committed to without upgrading either/both of these things? I understand the block will be open so now would be the time to do them, but a limited budget is a limited budget. I'm asking anyone offering input to account for that. I also appreciate that when I reach my 2020 goal of around ~650rwhp, my HP70 and stock R/T drivetrain may not love me. My hope, based on my research until this point, is that those components can hold strong and perform well until at least a year from now (when I get to my "phase 3" of this build).

If a new cam and upgraded heads are absolutely necessary, what are the most budget-friendly offerings you have seen that you could recommend?
You won't needs heads for ~650, but you WILL benefit heavily from a blower cam. Include that in your "must haves".

Try to find the injectors used, that'll save you serious $$, possibly even enough to grab a cam.

Sent from my moto z4 using Tapatalk
 
#3 ·
The hp70 will hold for awhile but that will start to slip eventually depending how fat your right foot is. The cam is a big yes song with that hellcat lifters and appropriate mds plugs. You will gain some with heads but you will gain more if you wanna stay under budget with headers. The api pump good. The heads come off though see if that builder offers any porting of any kind. Heads are coming off anyway. It always adds up, “oh I’m already there might as well add this or that” lol good luck.


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#4 ·
In my humble opinion... think of your engine as an air pump... People always say there’s “no replacement for displacement” I feel like those people haven’t played with boost... While you will gain some HP/TQ by building a 5.7 into a 392 stroker, when you start adding boost its going to be limited greatly by camshaft spec and cyl head flow. In my opinion a camshaft is a MUST if you’re going that far into the motor, and if it was me I’d vote ported heads over stroker crank if the budget only allows one... add a pound or two of boost and you’ll make up the cubes quick, the ported heads and cam will really help at that point. I agree with the headers too, boosted stuff NEEDS easy/free flowing exhaust... wether that’s cam, head work, or exhaust system itself. Remember you’re cramming the air in, it needs help getting out too...

That being said, if your goal is forged and the stroker crank price isn’t that much greater than a factory forged crank, I’d still do the cam (MUST) but maybe look into a 3 angle valve job (vs factory cut) for the heads as you’ll need springs anyway. Then in the future you can pull the heads again for porting if you’re short of your goals.
 
#6 · (Edited)
In my humble opinion... think of your engine as an air pump... People always say there's "no replacement for displacement" I feel like those people haven't played with boost... While you will gain some HP/TQ by building a 5.7 into a 392 stroker, when you start adding boost its going to be limited greatly by camshaft spec and cyl head flow. In my opinion a camshaft is a MUST if you're going that far into the motor, and if it was me I'd vote ported heads over stroker crank if the budget only allows one... add a pound or two of boost and you'll make up the cubes quick, the ported heads and cam will really help at that point. I agree with the headers too, boosted stuff NEEDS easy/free flowing exhaust... wether that's cam, head work, or exhaust system itself. Remember you're cramming the air in, it needs help getting out too...

That being said, if your goal is forged and the stroker crank price isn't that much greater than a factory forged crank, I'd still do the cam (MUST) but maybe look into a 3 angle valve job (vs factory cut) for the heads as you'll need springs anyway. Then in the future you can pull the heads again for porting if you're short of your goals.
Appreciating everyone's input.

Regarding the first point you make here, joeboy.. I agree with you and the primary reason I was originally intending to stay at 345ci of displacement is because I know I can reach my HP goals with the stronger internals and increasing boost. What I have come to learn is that it doesn't just seem to be a cam and the fuel system that need to be upgraded to support that though, and the pulley system would need to be upgraded too. It seems over 12-13lbs of boost is where most say the Whipple 2.9 starts to slip with it's stock pulley setup. If I am to believe that and go with the most popular upgrade option (the OST 8-rib kit), that's another $4k.

So that brings me to the far more cost effective option of going up in displacement and, for now, only going to about 12-13lbs of boost where I should be fine with my current pulley setup.

As an fyi - I realize longtubes add the most power and offer the best flow, but I have decided to just upgrade to a new set of 6.4 manifolds, high flow cats (or catless mids) and a 2.75-3" exhaust. I got a great deal on the manifolds and, given that I am lowered, the car is my daily, and I drive on NJ/NY roads, longtubes wouldn't be worth the potential gain if it affects my drivability. Also, if these 6.4 manifolds are good enough for a Hellcat and I won't be making a crazy amount more power than those, they will still be a significant upgrade.

Based on the feedback so far, I get the message that a cam is a must, so I will start hunting. That may be all I can do at this junction budget-wise so I will have to hope my stock 5.7 heads don't hurt me too much.
 
#7 ·
Interesting about pulley slip after that boost level, I didn’t know that. The 6.4 manifolds will help for sure, along with the exhaust stuff you mentioned. I totally get the trade off for streetability vs maximum gains. You may look into a hellcat cam, I think I’ve read of guys doing that for boosted stuff, and it would save you for sure to snag one of those here vs a custom cam.

joe
 
#8 ·
I'll say again, save the money on the heads....of you can have them ported on the cheap, then by all means go for it. They're not bad flowing heads as is and will support your goals.

My 6.4 is running stock heads, no porting and I'm putting 850-900 to the wheels, for what that's worth.

Do they help, yes, but with a Whipple set up, in incoming flow is actually more important than the outgoing. I know that doesn't make a lot of sense, but the outgoing air is already pressurized, facilitating an easier escape through the exhaust.

Heck, not only am I running stock heads, I'm running a stock throttle body with my Procharger.

Sent from my moto z4 using Tapatalk
 
#9 · (Edited)
I'll say again, save the money on the heads....of you can have them ported on the cheap, then by all means go for it. They're not bad flowing heads as is and will support your goals.

My 6.4 is running stock heads, no porting and I'm putting 850-900 to the wheels, for what that's worth.

Do they help, yes, but with a Whipple set up, in incoming flow is actually more important than the outgoing. I know that doesn't make a lot of sense, but the outgoing air is already pressurized, facilitating an easier escape through the exhaust.

Heck, not only am I running stock heads, I'm running a stock throttle body with my Procharger.

Sent from my moto z4 using Tapatalk
Do you have stock 6.4 heads or 5.7 heads though? I am assuming the 6.4 has better flowing heads than my 5.7. My concern is my stock 5.7 heads on a blown 6.4 motor. Definitely understand they're not optimal by any stretch, just wanted to confirm it wouldn't severely handicap my upgrades.

I still have my stock T/B too
 
#10 ·
I would say go ahead & do the MMX/Fore drop in pump that you can add a second or third to as your build continues. I started with the A2Speed & made it about 6 months before I had to change. Also definitely cam over heads as you'd only have to open the motor the one time, you can add heads later. Injectors for the Whipple are had to find used as they are super short. One thing that could easily help get you to your goals is switching to E85 using that MMX/Fore setup & the larger injectors will definitely benefit you. I picked up about 60 whp just switching to E85 with my Whipple & only running 6.5#s of boost.
 
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#15 ·
I have a blower cam , new left over from my current build. Paid almost 500 for it but asking 375 plus shipping. I can send the specs if interested.
I was reading one of the threads here about the head flow. I bought a pair of modified heads with valve up grades and machined C & C'd from Arrington engines. They would not at the time give me any flow data...said it was propriety info...so I sent the heads down to Dings racing to have them flow checked, and then posted their proprietary info. Long story short...he came back said the heads were good, nice flow and stuff but it was kind of a lewd point since I have a blower...but the cam was going to be the determining factor. I'm using a 3.6 LC KB with pulley setup for about 16lbs of boost. I had sent the snout down to CTP had had it extended so I now operate a stand alone belt drive. All the accessories stay on the stock belt and don't receive abnormal stress from trying to put too much tension from the blower. (an expensive mod by the way) Other areas I would consider is drive line, tranny, half shafts. (don't recall if you said these were already done) How about brakes?...will need to stop sometime. Also with running increased boost what are your plans to cut down on AIT temps...I have a stage 3 snow meth system, it will allow a more aggressive tune without the worry of detonation problems from heat. Here is a pic of my slow build money pit .

 
#16 ·
I have a blower cam , new left over from my current build. Paid almost 500 for it but asking 375 plus shipping. I can send the specs if interested.
I was reading one of the threads here about the head flow. I bought a pair of modified heads with valve up grades and machined C & C'd from Arrington engines. They would not at the time give me any flow data...said it was propriety info...so I sent the heads down to Dings racing to have them flow checked, and then posted their proprietary info. Long story short...he came back said the heads were good, nice flow and stuff but it was kind of a lewd point since I have a blower...but the cam was going to be the determining factor. I'm using a 3.6 LC KB with pulley setup for about 16lbs of boost. I had sent the snout down to CTP had had it extended so I now operate a stand alone belt drive. All the accessories stay on the stock belt and don't receive abnormal stress from trying to put too much tension from the blower. (an expensive mod by the way) Other areas I would consider is drive line, tranny, half shafts. (don't recall if you said these were already done) How about brakes?...will need to stop sometime. Also with running increased boost what are your plans to cut down on AIT temps...I have a stage 3 snow meth system, it will allow a more aggressive tune without the worry of detonation problems from heat. Here is a pic of my slow build money pit.
Please feel free to PM me the specs on your cam, including what year/model/engine spec you ran it on.

I mentioned above I'm hoping my drivetrain will last through to the beginning of 2021, at which point I would enter that phase of my upgrades. From what I've read, which I always take with a grain of salt, I should be ok at around 650rwhp/tq

I upgraded to Brembos all around. May upgrade to 6 piston fronts at some point, but the 4 pistons are still excellent so I feel fine with them for the foreseeable future.

My IATs have not been an issue at all to date (~35-40 degrees over ambient). This isn't a dig at all, but I've heard KB's have bigger issues with that than the 2.9 Whipples. Since I won't be increasing boost that much right now, I am not concerned at this stage.
 
#20 · (Edited)
Once you move to a forged piston the amount of boost is dictated by the fuel used . 93 pump will allow about 15 PSI. above that it's E85 or race fuel . I have a buddy with a forged 392 at 11:1 comp making 20 PSI on E85 . car makes upper 800-900whp( I don't know exactly ) your choice of the Hellcat cam is a good one for a 5.7 or 6.4 but IMO won't be enough for a 426.
 
#26 ·
#27 ·
Look into a Ram BGE, great foundation to start with. Same heads and block the Hellcat has. It's the route I went. Keep driving your car until built, then sell your engine to recoup some costs. I bought an oil pan and front cover to keep my 5.7 together for better resale.
Appreciate the outside the box idea. Did some research on the BGE after seeing your post yesterday and it does seem stout. From a budget perspective it makes little sense in my situation though. If I had a buyer for my 50k mile 5.7 block already it would be a nice option, but I'd have to pony up for the block, still a forged rotating assembly, cam, etc, shipping, install on all of it and then install on the whipple. I also haven't heard of anyone cracking these "standard" 5.7 or 6.4 blocks under 900+ rwhp/rwtrq, so I think it would be overkill for this build.
 
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