Stock Fuel Rails, why they don’t keep up

[jonx96]

" just a hellcat"


Best line of the day

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I actually hear that comment a lot. Usually by people who don’t own anything fast

 

[Hpindy]

I actually hear that comment a lot. Usually by people who don’t own anything fast

When did the hellcat go from being "king" to "oh it's just a hellcat "?????

These cars are a freak of nature .

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[jonx96]

When did the hellcat go from being "king" to "oh it's just a hellcat "?????

These cars are a freak of nature .

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When people who don't have them don't know better.
I keep wanting a gt500 to line up against me.

 

[vortecd]

When people who don't have them don't know better.
I keep wanting a gt500 to line up against me.

How many Hellcats have we seen compared to GT500? A lot! I think I have seen 3 GT500s and one was mid 9's but far from stock. The other 2 were high 10's

 

[Speedy!]

That's usually how it works. Add timing until no more power is made and then back off a degree or two. This of course assumes your not knock limited by fuel. The MBT table is that point I believe.

 

[16GoManGoHC2]

That’s a tough one to answer. I could go back and look to see what was added each pull. But these cars get to a point where 2 degrees doesn’t make much of a different. Off memory this was a max of 19 degrees of timing and 6500 rpm.
As far as times go at the track or street the ramp in of the timing is more important than trying to get every last degree. Same max timing but playing with ramp in of timing (stick car) worried about traction we were knocking time off like crazy.

Yep, 19 degrees of max timing, adding any more up top gained nothing, more boost would have but engine starts getting ahead of the blower after about 6200 rpm. Maybe a bigger TB might net a bit more breathing up top, running a 100 mm BBK ATM. Could be need more cam, or maybe both!! A bigger blower would help I’m sure, There’s no spinning this 2.4 blower any faster, +10 lower and 2.72 upper is all I’m going to ask out of it. Already spun the coupling once and had to pin it, should pin the gear on the other end too and the faster drivers side one as well, that puppy is turning 35,000+ rpm especially when I exceed 7000 rpm which I seem to not be able to keep from doing, it just revs so damn fast now. The boost is there soon as you stomp on it no matter if it’s only at 2500 rpm there’s 20+ psi in a instant. Here’s pinned blower coupling, blower side. Made a pinning jig myself, pinned with 2 3mm diameter x 10mm long hardened dowels. I should have used 4 at 90 degrees of each other but I ran out of 3 mm drill bits, the rotor shafts are hard as hell, each hole ate up 3 bits even using tap magic to cool and lubricate them. Used a grade 12.9 bolt as well with a custom centering washer the same OD as the ID of the coupling to keep it from twisting off center. The OEM the bolt head snapped off, found it between the coupling half’s, feel out when I took snout off. Spinning that blowers input shaft at 25,000+ rpm is putting ALLOT of stress on that little 17mm diameter shaft, no wonder it’s hardened.

 

[16GoManGoHC2]

Here’s what I found when I took the snout off. Luckily the rotor shafts are harder then the coupling hub and rotor shaft survived, new coupling from Bond was like 70$, and their not new!! Their take off used ones!! And the coupling inserts are $10 each, what robbery!! I’m making them myself for next time, their just black Delrin.

 

[BULL]

FYI, not all Delrin is created equal.

 

[Hpindy]

Yep, 19 degrees of max timing, adding any more up top gained nothing, more boost would have but engine starts getting ahead of the blower after about 6200 rpm. Maybe a bigger TB might net a bit more breathing up top, running a 100 mm BBK ATM. Could be need more cam, or maybe both!! A bigger blower would help I’m sure, There’s no spinning this 2.4 blower any faster, +10 lower and 2.72 upper is all I’m going to ask out of it. Already spun the coupling once and had to pin it, should pin the gear on the other end too and the faster drivers side one as well, that puppy is turning 35,000+ rpm especially when I exceed 7000 rpm which I seem to not be able to keep from doing, it just revs so damn fast now. The boost is there soon as you stomp on it no matter if it’s only at 2500 rpm there’s 20+ psi in a instant. Here’s pinned blower coupling, blower side. Made a pinning jig myself, pinned with 2 3mm diameter x 10mm long hardened dowels. I should have used 4 at 90 degrees of each other but I ran out of 3 mm drill bits, the rotor shafts are hard as hell, each hole ate up 3 bits even using tap magic to cool and lubricate them. Used a grade 12.9 bolt as well with a custom centering washer the same OD as the ID of the coupling to keep it from twisting off center. The OEM the bolt head snapped off, found it between the coupling half’s, feel out when I took snout off. Spinning that blowers input shaft at 25,000+ rpm is putting ALLOT of stress on that little 17mm diameter shaft, no wonder it’s hardened.
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The cam in these are more "emissions" oriented then power oriented. .. a PROPERLY" designed camshaft will definitely help in the upper rpm range ..
I have been testing this since last year ( I'm still testing now).
Also the poor little 2.4 supercharger can only spin so much before it become a inefficient furnace ..

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[Speedy!]

Cam in these is a monster compared to what was available for my old 5.7 based car, especially the RE cam.

 

[Hpindy]

Cam in these is a monster compared to what was available for my old 5.7 based car, especially the RE cam.

Yes . I tested the stock hellcat cam and the demon/RedEye cam .. there is still a bunch left on the table .. the demon cam is definitely better then the stock hellcat cam though ... But a proper aftermarket cam blows them both out of the water .. When i say proper in not talking about a " sound" cam .. I'm talking one actually designed for the engine under the operation conditions you will put on it ..

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[16GoManGoHC2]

Cam in these is a monster compared to what was available for my old 5.7 based car, especially the RE cam.

I gained nothing using the Demon/RE cam over the stock Hellcat cam, dyno was almost exactly the same no matter how I tried cam settings. If I was to do it again I definitely would’ve would go with a bigger cam instead of the Demon Redeye Cam, it was a waste of money.

 

[16GoManGoHC2]

FYI, not all Delrin is created equal.

the quality of Bonds bushings for the price is robbery, I could spin out better more accurate parts on my manually operated little lathe. I’ve cut allot of delrin in my days, there’s nothing special looking of what bond is using. We’ll see how they hold up. I’ve got other material ideas now since if got them sketched now to make some.

 

[Speedy!]

I gained nothing using the Demon/RE cam over the stock Hellcat cam, dyno was almost exactly the same no matter how I tried cam settings. If I was to do it again I definitely would’ve would go with a bigger cam instead of the Demon Redeye Cam, it was a waste of money.

That's interesting considering the profile difference. I could literally feel mine come much more alive above 4500. I'd have to find apples to apples time slips but my car trapped 3mph faster with the RE motor if memory serves.

 

[Hpindy]

I gained nothing using the Demon/RE cam over the stock Hellcat cam, dyno was almost exactly the same no matter how I tried cam settings. If I was to do it again I definitely would’ve would go with a bigger cam instead of the Demon Redeye Cam, it was a waste of money.

Maybe it's a M6 thing .. in my car there was more top end at the track . I have no dyno numbers though ..

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[16GoManGoHC2]

That's interesting considering the profile difference. I could literally feel mine come much more alive above 4500.

Trust me I was hoping for a difference but first dyno runs on the car on gasoline same basic tune just changes for the cam made the same HP, but a bit more TQ. Could be boost level differences between you and I making the small difference between the two cams (compared to an aftermarket not worried about emissions grind) seem even to the motor, ie Need a .620-660” lift cam with the right durations without too much of any overlap will be a measurable feel-able difference. Sad thing is I ended up changing springs that could have taken a bigger cam but already purchased a OST Demon clone cam, even sadder is I had a bigger .616 lift cam on hand but didn’t use it because I wanted to retain VVT for better street manners. Being a stick I should have listened to Cam Dynamics and went with their suggested cam that in their words “was what the hellcat should have come with”. But I’m pretty happy with where the car is at now power wise, I can tickle it with some spray someday if I want more. Next I’ll go back in time and talk about breaking the original 2.98 first Tranzilla and playing musical Diffs and talk about the title of this thread a bit and what I’ve found to be the RWHP limit of dual 285 pumps with E85 even with the fuel rail mods.

 

[Hpindy]

Trust me I was hoping for a difference but first dyno runs on the car on gasoline same basic tune just changes for the cam made the same HP, but a bit more TQ. Could be boost level differences between you and I making the small difference between the two cams (compared to an aftermarket not worried about emissions grind) seem even to the motor, ie Need a .620-660” lift cam with the right durations without too much of any overlap will be a measurable feel-able difference. Sad thing is I ended up changing springs that could have taken a bigger cam but already purchased a OST Demon clone cam, even sadder is I had a bigger .616 lift cam on hand but didn’t use it because I wanted to retain VVT for better street manners. Being a stick I should have listened to Cam Dynamics and went with their suggested cam that in their words “was what the hellcat should have come with. But I’m pretty happy with where the car is at now power wise, I can tickle it with some spray someday if I want more. Next I’ll go back in time and talk about breaking the original 2.98 first Tranzilla and playing musical Diffs and talk about the title of this thread a bit and what I’ve found to be the RWHP limit of dual 285 pumps eith E85 even with the fuel rail mods.

I wish I had of tested cams before you went through all this ... I was pretty happy with the demon cam until i tried my custom grind ....

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[16GoManGoHC2]

I wish I had of tested cams before you went through all this ... I was pretty happy with the demon cam until i tried my custom grind ....

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Is what it is, we live and learn and no one has a crystal ball, like I said I’m happy with the car, she runs strong, was better then just sticking with the stock cam as I would have then been wishing I did go with the Demon RE one. I think I’d need more blower for any more cam anyways at the moment. I’m stuffing her pretty hard already, seeing a PR over 2.5 in great air and aircharge approaching 2300 she’s breathing about at the limit of stock heads now too. So there’s more to just adding more cam to get bigger gains. I’m not up for that much work and money at the moment, this engine is too new yet to be tearing it apart again already and tossing out new parts, time to just drive it!! We’re good my friend, well, as soon as you get those dam rims down here!! (Just kidding, I don’t got tires for them yet anyways)

 

[Speedy!]

I feel like I'm close to the safe hp limit on mine at present. Depending on how things go I may eventually go drop in rods/pistons or 426(ish) and a Whipple if I wanna get silly.

 

[Hpindy]

That's interesting considering the profile difference. I could literally feel mine come much more alive above 4500. I'd have to find apples to apples time slips but my car trapped 3mph faster with the RE motor if memory serves.

That's what i noticed too when I went to the demon cam .. more top end .. sometimes the numbers don't change but the curve moves ...

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