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Discussion Starter · #1 · (Edited)
Ken Kamins noticed this when looking at the leaked HellCat engine spy photo, that the valve covers are taller over the intake side. He mentioned that is looks like a MultiAir set-up. I checked this out and Fiat did develop this technology.



Here is a description from Wiki: MultiAir on Wikipedia.

And here is a youtube video describing it:

I find this very interesting, especially since it look alike a Fiat/Dodge exclusive that brings more torque and HP while keeping efficiency high.
 

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I think you are on to something. MultiAir engines will increase power (up to 10%) and torque (up to 15%). Chrysler has already incorporated Fiat's Multiair head technology into the 2.0 and 2.4 Tigershark engines that are used in the Dodge Dart, Chrysler 200 and Jeep Cherokee and Renegade.
 

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I wonder how the airflow of the "Hellcat's" multi-air heads compares to the airflow of the GT500's DOHCs...
I couldn't tell you, however I have read the Eagle heads flow 302 CFM @ .600" lift vs. 305 CFM for the 5.0 Coyote. Obviously the 392's heads flow even better. Making power has never been a problem with any Hemi, but at high lift emissions become an issue, and I'm speculating this is the reason why the 345 hasn't seen a factory power increase since the 2009 model year. Just with the 392 cam, shorty headers, and a tune the 345 is right around 380 RWHP. If not for emissions reasons why wouldn't Dodge offer this cam right from the factory?
 

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If it includes Mutli-Air, the tuning on this engine, and the ability to modify it in the aftermarket, is going to be one hell of a task. I suppose it'll live up to the name of being a "Hell"cat.

The camshaft in the Multi-Air image would be modified to work with a OHV camshaft like in the V8 hemi. The image just gives you an example of the dimensions of the valve covers and comparison to the leaked photo.
 

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Something I can't understand: Whatever is above the row of intake valves seems also to be above the exhaust valves. Maybe not as tall but some mechanism is definitely there. As I understand it, Multi-air only controls the intake. Could it be Multi-air coupled with direct injection? Probably not but there is something different going on there.

I don't know why this hasn't gotten more attention. This is potentially a revolutionary engineering development with the Hemi. There is a whole lot about this Hellcat mill that we don't know yet and it looks like they did a lot more than just bolt a huffer on top of it.



Now will this Multi-air system (or whatever it is) make it to the N/A engines? So many unanswered questions!
 

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Wow major tech updates for the Hemi. This could be why the 6.2 can get 500s in "normal" mode with the maybe some sort to clutch to disengage and lower the blower gearing. Sure working on it is hard, but why bother, people don't buy factory supercharged cars to mess with them, if you want to do that just start with a 392 core.
 

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This could be the hottest thing to hit shelves since the Kate Upton in weightless environment photo shoot! :D
 

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I have been reading up on this MultiAir system because this is the first I have heard of it.

It seems to me, correct me if I am wrong, that this looks like a stop-gap technology.

If camless engines are our future, which I think they are, this will go the way of the Laserdisc in short order. In 5-8 years from now, this will be replaced with either camless or return to conventional cammed engines. In 10 years, nobody will remember how to work on MultiAir. Am I wrong?


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I have been reading up on this MultiAir system because this is the first I have heard of it.

It seems to me, correct me if I am wrong, that this looks like a stop-gap technology.

If camless engines are our future, which I think they are, this will go the way of the Laserdisc in short order. In 5-8 years from now, this will be replaced with either camless or return to conventional cammed engines. In 10 years, nobody will remember how to work on MultiAir. Am I wrong?
Seems just like a different take on variable valve timing that has been production cars for nearly 30 years. It does seem rather Rube Goldberg. I've always thought Nissan had the best version.
 

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Seems just like a different take on variable valve timing that has been production cars for nearly 30 years. It does seem rather Rube Goldberg. I've always thought Nissan had the best version.
I am no expert but, when I think of variable valve timing, I think of interrupting valves altogether to kill a cylinder. With this MultiAir, the valves open all the way under full throttle and open less (letting less air in and out) at lower power.


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Multi air is pretty much variable valve timing BUT it can control valve lift also. That's the big deal with it. Control of timing and lift of the intake valve.
 

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OK, thanks for the clarification. This still seems like a transition to camless. Obsolete tech in just a few years.

Tell me I am wrong and why.


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I can see camless electric solenoid controlled valves in the future. I believe there are some out there now but not in production cars.
 

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OK, thanks for the clarification. This still seems like a transition to camless. Obsolete tech in just a few years.

Tell me I am wrong and why.


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No you are right, but one could argue that all tech will become obsolete and replaced so :scratchhead: That's like saying flat tappet was only a step towards roller, or that solid was only a step towards hydraulic, or that optispark was a step towards true distributor-less, so on and so forth.

Personally, I'd say we are 8-10yrs away from seeing true camless in everyday production cars. It may hit the high end stuff in 2016 tho, who knows.
 

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I can see camless electric solenoid controlled valves in the future. I believe there are some out there now but not in production cars.
The Koenigsegg Cargine seems the best to me right now, I think they have been testing it for 3yrs now?

EDIT: Bingo, you just linked to it haha!
 

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No you are right, but one could argue that all tech will become obsolete and replaced so :scratchhead: That's like saying flat tappet was only a step towards roller, or that solid was only a step towards hydraulic, or that optispark was a step towards true distributor-less, so on and so forth.

Personally, I'd say we are 8-10yrs away from seeing true camless in everyday production cars. It may hit the high end stuff in 2016 tho, who knows.

Thanks for the discussion. I am not against the Multi Air system. Here is the thing. I plan on buying a Hellcat in 2016-2017 with the idea of keeping it for a long time. I also plan on using it for a daily driver. I don't want something that will be hard to find parts for in 20 years. If I was buying this as a throw-away car, it would be different. I would buy it, enjoy it, then move on.


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Thanks for the discussion. I am not against the Multi Air system. Here is the thing. I plan on buying a Hellcat in 2016-2017 with the idea of keeping it for a long time. I also plan on using it for a daily driver. I don't want something that will be hard to find parts for in 20 years. If I was buying this as a throw-away car, it would be different. I would buy it, enjoy it, then move on.


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It kinda worries me too. I also plan on buying one and seeing that it depends on a high pressure oil, it just screams more stuff to fail over time. I wish they had kept it simple like GM did with the LS9.
 
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