How much HP would this boosted motor make? (just looking for a 2nd opinion)

I have a project in mind that involves a boosted motor. I would be interested in what others opinions are as to what the HP and torque would be with a motor with the following specs.

2.25l (v6) at 9.5/1 static compression.

16 lbs boost

The motor would be "standard" as from the factory with the stock heads using na cams It is a 4 valve head

Motor would be intercooled

Boost will be provided by an Eaton supercharger

Red line will be 6500

I would like to think 250/250 is a reasonable number. Or am I being overly optimistic?

Eh, sounds about right to me, with compression like that. The tune will be important.

16 lbs from a supercharger? Seems like a lot, no?

I have boosted things more with superchargers.

And it is what the stock supercharger generates on this motor in stock form.

Depends on the compressor. If you were using an M45, I would be doubtful. An MP62, that should be in the ballpark. Go bigger and you should be past your estimate.

Given those particulars, I think 250 sounds low. If you can in fact feed that engine 16 pounds of boost and the appropriate amount of fuel, I'd guess you'd make roughly double what the same engine would make normally aspirated. So maybe 300? More?

There are plenty of hp calculators bouncing around the web.

IME, most 4-valve motors will make in the range of 60-70 ft-lbs of torque per atmosphere-liter of displacement. 2.25L, 2.1 atmospheres gives a range of 280 to 330 ft-lb. That's for NA and turbo cars, a belt-driven supercharger probably comes in at a bit less due to supercharger losses, so I'd guess 250-300. I'm also assuming it's been properly tuned and is using fuel with enough octane to not be detonation-limited before reaching MBT.

From there, horsepower depends on cam profile, runner length, head ports, stuff like that. If it's a 4-valve head revving to 6500 with decent ports and nice flow, I'd be surprised if peak horsepower was less than 90% of torque, so 250 sounds easily doable.

All numbers at the wheels, assuming RWD. FWD probably a bit higher due to lower drivetrain losses.

(edit, also assuming the supercharger is sized properly and is running reasonably efficiently at that flow level)

Borg Warner MatchBot, play with it. It's quite through and accurate when you adjust accordingly.

I smell a Mazda millennia 'round this thread. Nothing real to add.

singleslammer wrote: I smell a Mazda millennia 'round this thread. Nothing real to add.

Wasn't that the motor with the funny cams for miller cycle?

In reply to codrus:

Yes, it had a late closing intake cam to let the supercharger do some of the compression cycle and reduce pumping losses with the piston. I think that's the main idea of Miller Cycle. If they made an NA version, there's nothing to say you couldn't use NA cams with the supercharger for a conventional supercharged application.

Keith Tanner wrote: Depends on the compressor. If you were using an M45, I would be doubtful. An MP62, that should be in the ballpark. Go bigger and you should be past your estimate.

Having had a 45 and a 62 on a 2.0L engine, I would go with a 90 on a 2.25L. I think with a 90 you could reach the target with a little less boost.

Agreed, the 90 would be my choice. But Challenge guys do weird stuff depending on what they dig up

Ya I have been doing a tone of research on the miller cycle k motor and I was thinking about things and realized that all the hard fan work is done re the compressor and the associated piping and what not. I then started looking at cam profiles and figured out the I have two choices. See if a cam from the 2.5 will work but I don't think it will a drop in due to the intake valves being tilted almost vertical to narrow the heads so the compressor fits in the vally. This ends up being a good thing as the intake runners are almost a strait shot in to the chamber. But I digress. With the valves tilted up the spacing between the cams is less than the 2.5 so I think the gears on the cams ate smaller. There is also the issue of with the tilting up of the valves the cam from a 2.5 would have to be re clocked. With the auto cycle 2.5 max lift I at about 5:00 where as on the miller cycle and the valve being vertical max lift I at about 6:00. So with all those variables I looked in to the cost of just having the stock cams re ground to close the intake sooner. It turns out that is less than $200 per cam.

So for less than $500 I can convert the motor to a auto cycle with out dealing with re clicking cams. Basicly you wpuld want to mill off the back side of the lobes to close the intake sooner. Then drop the cam back in. This with the stock compressor putting 16 psi on it as it is and all the other plumbing an what not all done by the factory it seemed like a no brainer. All I would have to do then is probably up size the injectors and use A MS2. In theory I may be able to use the stock ecu with some hacking but I think stand allone is the sure fire way to make this work.

I don't know what I would put this in. Being it is a Mazda a Miata seems to be the natural choice I would start by getting ot running in a millenia first and then worry about its final destination later.

It just seems like the easy button for a very nice motor.

Does the valvetrain setup allow a regrind cam to be run, that seems like the easy button. when we looked into regrinding it was inexpensive, plus you could knock off someone elses aftermarket cam specs, like the ever popular 272 or something more conducive to boost

just a thought

In reply to dean1484: What fuel will you be using? Pump grade 91/2 octane? Or E85? The difference will be significant. Assuming you can tune for the 92 octane pump gas you will be down 35 to 50 horsepower over what you could pull with E85.
While it's true you'll get better fuel mileage with 92 octane Pump gas. The cost of E85 when I drove by the local station more than made up the difference..

I am going with 93 octain as that is what we have around here. E85 is not easy to find around here. In fact I am not sure where to get it these days. The one station that I knew had it stopped selling it.

Opti wrote: Does the valvetrain setup allow a regrind cam to be run, that seems like the easy button. when we looked into regrinding it was inexpensive, plus you could knock off someone elses aftermarket cam specs, like the ever popular 272 or something more conducive to boost just a thought

I don't see why not. Other than the valve angle there I no difference from the 2.5. With a re grind I am just taking metal off the back side of the lobe. And yes there is the opportunity to tweak the grind to optimize the boost however I don't want to do it at the expense of na performance.

Oh on a side note looking at the stock miller cycle intake cams. They look like a cam from a roller lifter SBC.

Regrinding cams is not all that expensive. I have a quote in hand for substantially less than $200/cam. This is only to remove metal and re-harden it.

I will need gaskets and probably lifters as well so I am looking at $500 in parts for that. I have not looked at the injectors yet but those I don't think will be an issue to get higher lb/hr units. All this is just parts swapping. No fabrication. This is what makes this speaking to me. The time spent fabbing up an aftermarket supercharger and all the piping and intercoolers plus unless you are an exceptional fabricator it will look bodged together and I bet you will be out more cash and time finding parts and making things fit and work. Whereas just changing the cams and injectors is a leisurely Saturday of wrenching.

The other piece of the puzzle is the ECU and I just jumped directly to MS. But there is a possibility that the stock one could be used. I assume that these have been hacked due to the Miata crowd. It would great if the stock ECU could be used with the fuel and timing tables adjusted but that is probably more work than just going MS from the get go as I am very families with MS and have a bench tested MS2V3 on the shelf. The only thing that would tempt me is if the PNP unit for the Miata could be used with the factory Barnes. That would be the best of both worlds. I have not looked at that yet. I have been concentrating on the logistics of the motor.

Even if I keep the motor in the millennia body it would make for an interesting ride. At that point, I would have to look at the transmission and see what its limits are but that I getting way ahead of myself. But to sure would make a great sleeper. I don't think there is any real way to do this on a challenge budget but that was my original plan. Unless I could get a good running millennia for $500.

Section of a KJ-ZEM

You can see that the intake valves are almost straight up whereas in a KL motor the intake valve angle is the same as the exhaust.

That's a very trick intake setup. Very compact for a four cam engine.

Yes!!! That is another reason why I have been fascinated with trying this.

So far I don't see a reason why it would not work and at the end of the day, I think it will end up being a lot less $$$$ and time as compared to trying to add a supercharger to a KL ZE or something like that.

A huge part of doing a forced induction project is the mounting of the supercharger and getting the pullies aligned up and making it so it fits. It is the packaging. I have done this and it is just a PITA that never looks factory. Not hard just finicky and it always looks a little hacked. Then there is all the plumbing and the intercoolers. All would have to be fabricated from parts from different places. That is a lot of time and always ends up costing more $$$$ than you think. All those little things add up fast.

For now the intent would be to keep it in a Millenia. I really like the look of the later ones. Say 2000-2002 I think and they are now emission exempt. The early ones have a bit to much of the 80's and 90's design that was buffed off with the later ones.

2002

Versus a 1997

The ultimate destination would be to transplant it into a Miata. This would require sorting the motor mounts and I will probably have to deal with the oil pan and the pickup as the motor will be coming out of a FWD car.

I am not looking for huge HP and Torque. I was aiming for the mid 200's but reading what others have posted it seems that there may be a bit more in there. That would just be a bonus.

I just think it would be cool to put this motor in a Miata in autocycle form. It would be "factory" and I think that alone would be a really really cool thing. Almost like it is the motor that should have been there.

About the only thing I would need to do is deal with the air flow to the intercoolers on the KJ ZEM or worse case ditch them and run a FMIC but that I would probably just call Keith up and I am sure he has something already designed that would be a bolt in.

On another note, I was looking at the sections above and the injectors are aimed almost directly at the back side of the valve. Never noticed that before.

singleslammer wrote: I smell a Mazda millennia 'round this thread. Nothing real to add.

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