Newbie thinking out loud - power potential of 3.0L engines

[Jetmugg]

I'm just doing a little brainstorming / daydreaming about potential projects right now (thinking about the future).

Anyway, since you guys are the best source of information on these 3.0L V6 engines, what do you think about the power potential of a 3.0L V6, especially when compared to something like a VR6 VW engine?

I'm thinking specifically of non-street racing type applications.

Can a 3.0L V6 turbo engine be built to make somewhere in the neighborhood of 500HP, for example, with dedicated "race" turbo selection, big intercooler, etc?

Any guidance for someone new to the game would be very much appreciated.

Steve.

[Reaper1]

A 3.0 can be built to make 500hp with a non-dedicated "race" turbo selection! Brent (Ondonti) has proven that with relative ease. The biggest trick seems to be tuning. The strength of the engine, especially the bottom end, is not in question at all. The heads and their supporting hardware in Chrysler guise leave a bit to be desired, but it's nothing that can't be worked around. IMHO nobody has really publicly pushed the SOHC 3.0 to the very edge yet. My own personal opinion is that with the correct hardware and tuning it should be able to make 700hp. That won't come as easily as if it were done with the DOHC heads, but I do think it is possible to pull off...

[zin]

500hp won't be too hard at all.

Shopping list: stand alone ecu (megasquirt, etc), suitable turbo and associated plumbing (intake/exhaust as well as oil/water), forged pistons for added safety, clean up the cylinder heads and intake, see the V6 section for ideas/weaknesses that should be addressed and you're there!

500HP seems like a lot, and it is, but a wise man (and a few women) have told me that a "good big one" is better than a "good small one"! You're starting with two more cylinders, and more displacement, as well as other things that are in your favor...

The one thing working against you, and it's not a small thing, is that there isn't much aftermarket support for these engines, so you'll have to fabricate/have fabricated most of the "trick" parts you may want to have, such as cams.

Speaking of which, once you have the stand-alone ECU, you'll be able to realize a pretty big bump by upgrading the cams, even if they are still "turbo compatible", as all OE cams are a compromise between power, mileage and emissions and so valve lift/duration tends to be less than optimal, just don't get carried away, with cams, once you pick a cam, actually buy the one two-three steps below it! Small steps = a better experience and an easier tune.

Having said all this, my experience with Chrysler V6s is very limited, there are a number of guys here that can give you better, first hand advice, a quick look through the V6 section will make them obvious.

Best of luck with the build!

Mike

[Jetmugg]

The aftermarket support vs. overall power potential was one of my areas of concern. This daydream is related specifically to land speed racing in the F/MMP and F/BMMP classes. Those classes decode to F= 2.016 - 3.014 Liter Displacement. MMP = Modified Mid/mini Pickup trucks. BMMP = Blown Mid/mini Pickups.

For reference sake, the current records in those classes at Bonneville are 159.8 mph and 189.6 mph, respectively. The MMP record is held by an extended cab Toyota pickup, presumably running a 3 liter Toyota 6-banger. The BMMP record is held by a VW Rabbit Pickup, running a turbo VR6 for power.

VR6 is the main competition in my mind's eye, as it seems to be the best fit in a small FWD truck. I am hopeful that a Rampage would be more aerodynamic than a Rabbit pickup.

There is a ton of aftermarket support for the VW VR6's, which is a major consideration. If you had a choice between a VR6 and a Chrysler 3.0, which one seems to have the better power potential? The Chryco stuff should be easier in terms of transaxle fitment, axle compatibility, shifter setup, etc., whereas the VW seems to offer more in terms of aftermarket hard parts and tuning options.

Anyway, I'm just dreaming and learning right now, I can't afford another engine program at this exact time (need to let my credit card cool off some).

Steve.

[zin]

Sorry to say, but, from an aftermarket standpoint, the VR6 will beat the Chrysler 6s.

To reach your goals at the lowest cost, and or with the greatest ease, the VW would be the direction I'd probably go ... but for style and "brand loyalty", the Chrysler 6 can get the job done.

Might check with Chrysler to see if they'd be willing to provide technical assistance, or possibly parts ... I don't think you could expect actual $$,but you won't know until you ask!

Mike

[Shadow24]

The other option is to go with the DOHC 3.0L found in the 3000GT/Stealth and a few other cars. There is decent aftermarket parts for the DOHC motors and the heads flow a heck of a lot better than the SOHC variants (both 12v and 24v). The 3.0 can also be revved pretty high (into the 9000rpm range) and takes boost fairly well, with good pistons. Add in a good EMS (like Megasquirt with a few add-ons), and I think you could give the VR6 a good run for the speed record.

[c2xejk]

On the SOHC vs DOHC heads, I think the big difference is valve size... If the class doesn't distinguish based on number of valves, yeah I would go with a 4-valve/cyl engine.

With a more aggressive cam, the 12v could do much better than it does. However, it is hard to over come the valve area advantage of a 4v/cyl head...

[Jetmugg]

Will the DOHC (3000GT/Stealth) engine work in a transverse-mounted application? Is there a FWD transaxle that would work?

[c2xejk]

The Stealth/3000GT engine is transversely mounted. That said, I think it is mounted opposite how it is in Chrysler vehicles. To swap it, you would need the oil pickup, pan, and maybe the pump. I have not done that swap, so there easily could be something I am missing... Going with a 24v SOHC 3L may be an easier way to go.

[zin]

Time to reconnoiter the differences at the J/Y...

Mike

[Reaper1]

It is totally possible to bolt a DOHC engine to one of our transmissions. Yes, in the 3Si cars they are turned around 180*, but the engine still runs the same direction, so that is what allows it to be used in our cars. That being said, there are a LOT of differences between the DOHC engines and the SOHC engines. Brent has done a LOT of show-and-tell when it comes to this stuff.

The VR6 engine might have the advantage as far as aftermarket support, but in the end I think the 6G72 has the power and durability advantage.

[Ondonti]

There is really a lot more to it then making the power. If you are going for using stock parts on the cheap or if you want built parts. Sorry but there is plenty of support to build a shortblock no matter what heads you have on it. There are billet crankshafts of multiple displacements, etc. I don't know that VW has much more support stateside. If you are in Europe then its a different matter.

Since you have to stick 3.00L or smaller then you have your limitations on choices.

I would worry more about the transmission but land speed is probably not that harsh on things.

If you are going to be using racing fuel then its going to be very easy to survive higher power levels. I ran 91 octane and methanol at too high power levels. The "flow" setup (heads, cams, manifolds) will determine how much boost you need to make the power you want and how wide your powerband will be but the shortblock really won't care much. Higher boost is still going to be about the same final compression ratio and combustion pressure level as a better flowing setup, just can't run the same timing. Since 12 valves can run the same rpms as a 24 valve 6g72, most of the reasons people think import motors will make more hp/liter are irrelevant. All you have is the efficiency difference. The more you knock out bottlenecks the less it really matters. The advantage 4 valve heads will always have is powerband width when pushed to the limit. I am pretty sure a well done 12 valve can make good power from 4500 to 8000+rpm and thats a giant powerband.

vr6's come in 12 valve and 24 valve and the difference is there but I know people are not maxing out either setups potential. Again, the reason for small differences would be that they can both rev the same, you just need to be able to flow up there which requires more work on a 2 valve head.

[Shadow24]

Another benefit of going with either the 24v SOHC or DOHC, is you get a forged crank from the factory. The 12v has a cast crank and Ondonti can tell you first hand, they do bend.

[c2xejk]

Not sure about the other variants, but the 6g74 SOHC has full floating wrist pins. (vs 12v press in wrist pins.)

[zin]

Sounds like ones may be able to cherry pick parts from the various incarnations to build a pretty stout "factory" engine, if budgets are a constriction, or you'd like to say you did it with (mostly) factory parts ...

Mike

- - - Updated - - -

Sounds like ones may be able to cherry pick parts from the various incarnations to build a pretty stout "factory" engine, if budgets are a constriction, or you'd like to say you did it with (mostly) factory parts ...

Mike

[Jetmugg]

Budgets are always a restriction, no matter what level of the game you are playing. Part of the consideration has to be along the lines of "which drivetrain combination can get me to my goal in the most cost effective manner". I agree that a 24V looks more attractive on its surface when compared to a 12V, in terms of flow potential, and usually in terms of spring seat pressure and ultimate rpm ability.

The general thought with most LSR attempts is to make power at higher rpm levels, as opposed to lower rpm "torque" engines. (Yes, I know that the two are not possible to have without the other". Some of this is limited by the available gearing, and by the tire sizes that will work with a given chassis.

Let me run my disclaimer now: - I am committed to running the engine that I already have in my Rampage, I already have another engine "on deck" for a different class, as well as one or two other engines for even more classes. The 3.0L modified gas classes would most likely be run several years down the road.

Anyway, the current recordholder in F/BMMP is still getting his VR6 sorted out. I suspect that he will run 200mph in 2014. For reference sake, he holds the 2 liter BMMP record at 194. That's 194 mph with a turbo 2-liter VW engine in an '81 Rabbit Pickup.

So, when I start playing with the math to run 200mph, I typically start calculations with the tallest available gearset, the tallest tire that will fit in the fenderwell, and work backwards into engine rpm's. I'll have to do some research on gear ratios, which are probably the biggest limiting factor. Tires in the range of 21-25" height will be OK, anything bigger starts to have clearance issues, or raises the little truck quite a bit.

It is certainly possible to cherry pick parts, and run any combination that will work in the Modified classes. Race gas is part of the deal, with Octane ratings up around 114 available from the event's supplier.

Right now, it's a daydream for 2-3 years down the road, but I like to start gathering knowledge as soon as possible.

Steve.

[Vigo]

So... If your car is already setup for a VW trans, wouldn't it be relatively easy as far as trans and axles to put a vr6 in your truck? At that point it's just a couple motor mounts and engine management to figure out.

[Shadow24]

gear ratios should be OK as well. Squirrel performance shows a stock A543 (3.77FD) with a 25" diameter tire and an 8500 rpm limit, tops out in 4th at 173mph, and 5th at 236mph. if you have to, you can switch out a 3.5:1 final drive ratio and get 186/254mph.

Additionally, there are versions of the 24v SOHC with 9:1 and 10:1 CR, but the pistons arn't that great under boost in stock form. Re-gapping rings and having a good tune will go miles for longevity. Is there a particular EMS you are looking at for this setup? I am personally partial to the Megasquirt platform due to it's flexibility (not to mention it is already used on some LSR vehicles successfully already).

[Ondonti]

I don't know about putting that much power through 5th gear. Nobody does it. 9000 rpms on a 568 with 3.50 ratio and 25" tire would get you 203mph in 4th. 9500 goes 215. 26" tire @ 9000 goes 212.

Stock rods have been run over 9500 rpms and there is currently a sale on cheap aftermarket rods http://www.3sx.com/store/comersus_viewItem.asp?idProduct=26904 I don't know if they will actually take more rpms then stock since ARP2000 material has never performed better then OEM for certain fasteners.
Brian Crower sells rods that can be purchased with ARP custom age 625+ rod bolts. I know you can buy the bolts separately from ARP.

Hydraulic lifters are a problem at high rpms (DOCH) and will be much worse in a land speed car. The solid lifters available seem to break rockers but the info out there is not clear. Nelson is running 11,000 rpms but who knows what his valvetrain looks like. He is running dry sump oil systems.

I think the gearing thing is a problem. I would love a custom final drive if any one wants to make one :P I would not run 9000 rpms simple because I didn't have the gears I need. I would run 9000 rpms because I want to make power up there or think I can do it reliably.

I would assume the VW transmission is going to be cake as far as gearing goes. There have to be custom gears etc out there. Any engine will make power. Not every transmission will work out :(

[Jetmugg]

There is a fair amount of aftermarket support for the VW transaxles, as they have and are currently used in a variety of racing applications. In fact, VW Motorsports (factory VW supported) has a pretty wide variety of offerings.

I certainly agree that I wouldn't want to run 9,000 rpm's for 5 miles straight. Something more reasonable (maybe in the 7,000's) seems more plausible.

[Ondonti]

So the real question is 5th gear. I don't see myself building a car that needs to use 5th gear when 4th gear is already too long for the 1/4 until you go into the deep 8's.

[Vigo]

Well, on the dodge trans with 5th being right next to the bearing plate i would think it is one of the stronger gears, but that's just an educated guess.

[Sundance 6g72]

I think 8000rpm is a good RPM goal for a landspeed car. I pushed my valvetrain to 8000 and everything seems fine. 3.3dodge valve springs, LS1 Retainers and locks and 270 duration cams.


Honestly, a DOHC 24v 3.0 will do well over 500whp on a good tune with easy as long as the turbo system and fuel system will support it. With race fuel, you can plan on over 700whp as long as the tuner knows what he/she is doing.

I like the 12valve for cheapness. Valvetrain parts are cheep, cams are cheep. I can get a full 12v motor for under $150 and plan on it handling my 315hp tune with ease on e85. Headflow is the issue on the 12v when going for high horsepower. Im fine with turning up my boost.. my car was just a street car though.

[Ondonti]

Well, on the dodge trans with 5th being right next to the bearing plate i would think it is one of the stronger gears, but that's just an educated guess.

There were quite a few people saying they didn't like 5th gear for strength. Probably nothing to back that up. Would not be the first time everyone was wrong! I would never want to test this as even if it was possible safety wise, 200mph winds would put a real load on the engine and I would never need a tune that was safe at 200mph brick wall of air speed. I do tool around a lot with 5th gear and boost but thats not a racing gear for me. Street racers probably get more into that gear.

Is this a salt flat car or what? Kinda far away. I never even visited when I lived in Utah :(

[Jetmugg]

Yes- this is a purpose built Salt Flats race vehicle.

[Reaper1]

My only questions about using 5th for a lot of power are: the gear strength themselves and the actual shafts. That gear hangs off the shafts on the very end. I've got the personal goal of hitting/sustaining 200mph+ in my car (not trying to break records, I just have the goal for myself and the car) and have always calculated it used 5th gear and then using tires to alter the FD without having to get super expensive using custom gears. My rpm ceiling I put in for myself is 8000 with engine redline at 8500. If I can get it lower, that's even better. I'd rather not have to rev the engine that hard.

[Jetmugg]

Agreed - my Rampage is currently using a VW / Dodge Omni 4-speed transaxle. There is an overdrive 4th gear that matches the overdrive 5th in some of the later transaxles. The designs are similar to the Dodge transaxles, in that the 5th gear is basically an "add on" gear to the end of the shaft. Talking to my transmission guy, he felt that the 4 speeds were much more durable. The biggest issue is that the 4 speed is a much wider ratio trans than the 5 speed.

[Reaper1]

The VW 4-speed has the 4th gear outside of the case? I thought they were contained within the case? Which VW tranny again? I just want to look at it for myself for curiosity/educational purposes.

[zin]

I think he was referring to the 5-speed VW transmissions, not the 4-speeds... The confusion may be in that he also mentioned that there was an overdrive ratio for 4th that was the same as that in the 5-speed, but that it made for a very wide ratio 4-speed.

Mike

[Reaper1]

Man, I hate to say it, but I'm still confused! LOL

[Ondonti]

Man, I hate to say it, but I'm still confused! LOL

Sounds to me more like that the 4 speed had an option to bolt on a 5th gear (overdrive) but since the 4 speed has wider gear spacing (not intended to have a 5th gear) you don't need 5th gear in power situations.

I volunteer to build a car and Reaper can do the 5th gear testing :P I think half the car will be torn off since I won't build it for completing the high MPH test :P

One hard thing is that you need a big turbo high rpm setup to really require 5th gear and that means you have to be going really fast just to put a decent load on it. I figure 4500 rpms min for a lot of setups to start peaking torque and thats 130mph to start :P

[Reaper1]

Sounds to me more like that the 4 speed had an option to bolt on a 5th gear (overdrive) but since the 4 speed has wider gear spacing (not intended to have a 5th gear) you don't need 5th gear in power situations.

I volunteer to build a car and Reaper can do the 5th gear testing :P I think half the car will be torn off since I won't build it for completing the high MPH test :P

One hard thing is that you need a big turbo high rpm setup to really require 5th gear and that means you have to be going really fast just to put a decent load on it. I figure 4500 rpms min for a lot of setups to start peaking torque and thats 130mph to start :P

That's how I interpreted his description of the 4-speed...that it had the option of bolting on a 5th gear just like our transmissions.

Brent, if we tear off half the car, then the load will be different! LOL Maybe we build a van, load it with crap to make it really heavy, then load it down to test 5th. ;) We could put really small tires on it so we don't have to be going a million mph to get in the upper rpm's in 5th.

Sound like a plan? :deal: :D