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Discussion Starter #1 (Edited)
I don't mean this to be an MSM-bashing thread, or another Turbo vs S/C thread. Hope it doesn't go that way. I'm just under-informed on turbos, and that's probably half the reason I prefer superchargers (not centrifugal, tho).

I test drove an MSM yesterday just so I could rest-assured that I was making the right move, here. I've owned a Miata before, and I've always been a fan. Overall, I liked the car. However, it reaffirmed my negative affinity for turbochargers. I had heard that turbochargers had come a long way since the late 80's/early 90's with regard reducing lag.

So does the MSM have more lag than typical these days, or am I just spoiled on twin-screw superchargers? Don't get me wrong, the MSM has plenty of power, but I want right now throttle response, and I prefer a broad torque spread. I liked the ION Redline alot better in that department, and I sorely miss my GTP.
 

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This won't answer your question, but gives a few thoughts on the subject.

define the lag you felt. if you are at 3000 rpm, and jump on it, you will not get the same response you will if you start at 4000rpm

Here's a good link, a "break-in on the engine" thread that describes not all MSMs drive as aggresively out the door:
http://forum.miata.net/cgi-bin/ultimatebb.cgi?ubb=get_topic;f=6;t=021581

The MSM has awesome oversteer control, especially fun when turbo throttle enduced

Some are considering modifications such as boost controllers etc

with the cost of speeding tickets and associated insurance cost, I'm happy enough with the stock power!

I look forward to driving a SC car, but I won't drive them unless they are serious roadster competition, and in the sub $25K range. Name one, and I'll be out the door!

RODEO
 

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I noticed same thing when I drove it - the peak torque is at 4500 and the peak power is at 6000, redline is like 6200 or something (Rodeo?).

I kept thinking "where's the oomph?," then it would come on and *bang* I'd go headlong into the rev limiter.

I really am hoping for something more along the Saab V6 2.8L turbo-like performance out of the F/I Solstice - peak torque down around 2-3000 RPM's.
 

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solsticeman said:
I noticed same thing when I drove it - the peak torque is at 4500 and the peak power is at 6000, redline is like 6200 or something (Rodeo?).

I kept thinking "where's the oomph?," then it would come on and *bang* I'd go headlong into the rev limiter.

I really am hoping for something more along the Saab V6 2.8L turbo-like performance out of the F/I Solstice - peak torque down around 2-3000 RPM's.
Here's a partial quote with some numbers (lacar.com):
MazdaSpeed adds an IHI ball-bearing single-scroll turbocharger with a Denso air-to-air intercooler carrying 7.25 psi of boost. This brings horsepower up to 178 at 6,000 rpm, and torque to 166 lb.ft. at 4,500 rpm. At 60 mph, in sixth gear, the tachometer is registering 3,800 rpm, right in the sweet spot for the turbo, giving immediate acceleration.

What I find interesting in S-Man's comment is the 2-3K peak torque! The S2K is way to high, the MSM is to high, the F/I Sol is just right? Sounds like a kids story I know :lol:

But, I agree with S-Man in that the range of power is basically 3500-6500. I have a lot of fun with that, feels like a race car (autox), but it is definately a "to each his own". Even the miata community is split on this one.

I do know the guy who produced the video in the post below bought a secong MSM for his racing team as turbos have recently been allowed, that says something, no?

http://www.solsticeforum.com/forum/showthread.php?t=1303
http://www.solsticeforum.com/forum/showthread.php?t=1303
 

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question, isn't it a point, if the peak torque is at low rpms(2-3K), the car won't have it at higher rpms (5-6K)?

Perhaps you want the peak at 2-3K because you like the power off the line, whereas, I like the power on a downshift acceleration pass - IOW, if I'm running at 3500, and I need to pass, I drop a gear and I'm gone. Maybe this is the preference difference were not talking about, but should be???

Could make it interesting as both the stock and sc Sol comes online?

RODEO
 

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Discussion Starter #6
RODEO said:
define the lag you felt. if you are at 3000 rpm, and jump on it, you will not get the same response you will if you start at 4000rpm


RODEO
What I'm talking about is it seemed like no matter what RPM I was driving at, if I whacked the throttle, it would take a second for the power to really come on, and I could hear the turbo spooling up. It was quicker at higher RPM, and I understand that is just the nature of turbos.

Once the turbo started to kick in, the acceleration was intense, but very non-linear, and before I knew it, I found the "shift indicator." By "shift indicator" I mean rev limiter. It just didn't seem very predictable to me whatsoever. I guess after a day or so of driving the car I'd get used to it. It just seemed to me that If I really needed throttle-on oversteer in a turn, I'd have to place my order with my right foot, and wait a second for the power to arrive.

Also, at half throttle, trying to drive in a civilized manner, it would seem to just take off on its own once the turbo caught up. It felt like someone else was pushing the gas pedal for me. Again, maybe that's just something that would take a little getting used to. It WAS a fun car to drive, don't get me wrong, just a little foreign to my senses.
 

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Discussion Starter #7
RODEO said:
The MSM has awesome oversteer control, especially fun when turbo throttle enduced


RODEO
Oh yah. That was what I loved so much about my '91 Miata. It was just so rediculously easy to drive in a rediculous manner. It was far and away one of the best cars I've driven with regards to steering with your right foot, even without an uber-powerful engine.
 

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RODEO said:
question, isn't it a point, if the peak torque is at low rpms(2-3K), the car won't have it at higher rpms (5-6K)?

Perhaps you want the peak at 2-3K because you like the power off the line, whereas, I like the power on a downshift acceleration pass - IOW, if I'm running at 3500, and I need to pass, I drop a gear and I'm gone. Maybe this is the preference difference were not talking about, but should be??
I do want to address this question for educational purposes, and in the meantime we can move on with the discussion.

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no worries 2KWK4U, you've treated the MSM with respect, and that's the way a car discussion should be! no bashing allowed.

one review wrote something I likes, it went something like this:

the MSM has the best of both worlds, before turbo kicks in it can be used as an around town car that drives like a NB would, and if you feel having some fun, the turbos there for you.

NOW, I think there's a trade-off to that, if the car is set up to be tame below 3500rpm, and a runner above 3500, then the transtion will suffer, and that is probably more a problem as the MSM turbo is not setup aggresively (although it can be modified). So, this set up will turn some off, and make others happy, much like a small trunk will not bother some, and for others it's a deal breaker.

My experience with the MSM is, it's not a car with immediate acceleration at any rpm, but once you have it in the rpm range where it runs best, it runs fast. seems this is a great setup for autox to me.

as you even said, you have to somewhat plan for the acceleration, but, in autox, aren't you always planning for acceleration, thus, it's always there. when I'm having fun with the MSM, it's already in the sweet spot. But if I try to jump on it to impress a BMW sedan, I'll get smoked :lol:
 

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Rodeo said:
...question, isn't it a point, if the peak torque is at low rpms(2-3K), the car won't have it at higher rpms (5-6K)?...
Not always - it all depends on how you set up the torque curve, and how you manage the waste, PLUS whatever other goodies you can play with (VVT, engine tech plusses like direct gas injection, etc.).

Most (not all, but most) of the torque curves I've seen for 4-cylinder turbo engines climb at some rate to peak torque, then become a flat top to peak power as the power rolls off, considerably different than a N/A engine. The slope of the climb rate is a decent indicator (not an ABSOLUTE PREDICTOR, mind you, just an indicator) of turbo lag.

If you allow boost to build earlier, by using smaller or lower inertia turbines as just an example, you can reach peak torque earlier with wide-open-throttle application, and let the waste gate handle the overboost.

Some of the variable-vane turbos I've seen have incredibly low peak torque (<2000 RPM) while maintaining a very high torque all the way up to within a few hundred of redline for peak power.

It CAN be done. I can't say whether GM will or can do it. I'm surprised that the peak torque for the Miata is so high - I would have expected it to be closer to 3000 RPM.

Is a 235 ft-lb at 2800 RPM / 230 hp at 5500 RPM with a 6500 redline 2-ish liter turbo feasible? With today's technology, you bet it is.

Can GM Powertrain make one? ****Shrug**** I certainly hope so.
 

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Nice S-Man! So, what I hear is it can be done, but hasn't yet in a sub 25k roadster. I think tha's important to keep in mind here. We could have another thread going on about "what is possible", but we've had enough of those. Let's talk about what exists. Right now, I'm driving a roadster, that counts for something, a smile every day! :)

Now, we've realized the MSM is what it is. the question was: will a S/C automatically resolve this problem.

remember, I have no problem selling the MSM should a car that exists (or soon exists) run better :) Of course I'd still have the top and trunk issues to contend with :willy:
 

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The troll in me says drop a V6 in it, get it :devil:
 

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solsticeman said:
I'm surprised that the peak torque for the Miata is so high - I would have expected it to be closer to 3000 RPM.
I searched mazda-speed.com forum for "turbo lag", thought this was interesting:

QUOTE:
source "elitetech" from mazda-speed.com
MSM with boost controller

I just installed boost controller couple day ago and very happy with it. The most gain with the least amount of money.

Before: No boost in first & second gears. Boost start at 3500-4000 RPM. Full boost at 8-8.5 Psi

After: Some boost in first gear, and up to 8 Psi in second. Boost start early as low as 2800-3000 RPM. Full boost holding at 10 Psi.

Conclusion: Factory boost controller not only control over boost, also prevent boost at low RPM as well to keep miata easy to drive. Therefore, the turbo its self was not the reasons for turbo lag. IT WAS THE FACTORY BOOST CONTROLLER.
After, I installed the controller in the car, it drive like a moster with a happy tail.

The not happy part was: During the test drive in the rain (I known, but I can't wait) the car spun out during third gear acceleration. So Be careful. Lucky, after two circles on the grass it jump back on the road, where I'm able to step on the gas and straight up the car. End up with a front flat tire. Very luck,

I have installed pictures, who want to post them let me know I email it to you.

ENDQUOTE

So, careful what you wish for :lol: RODEO
 

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Discussion Starter #13
Sounds like you ought to get one, RODEO. Let us know your impressions. Lemme know when I can test drive yours w/ the new boost controller :devil: :thumbs:
 

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2KWK4U said:
Sounds like you ought to get one, RODEO. Let us know your impressions. Lemme know when I can test drive yours w/ the new boost controller :devil: :thumbs:
Well, being I can spin this car out in 1st 2nd and 3rd, I think I'm going to stick with what I 've got until I learn for sure I can handle this much power.

I drove a GT Mustang once, threw it into a 180 without even trying, scary when not expected.

I was in the rain the other day with MSM, punched it from first to second, when the turbo kicked in in second gear the back end started coming round, and I was going straight until then :lol: Thankfully the steering on this car is practically self correcting, and I had no problems. It will be a while before I need more power, right now it would be nothing but trouble. Seems the MSM is set up for newbies to power like me. Once I get bored, a $350 boost controller mod will get the smile back on my face again.
 

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2KWK4U said:
Lemme know when I can test drive yours w/ the new boost controller :devil: :thumbs:
Well, after me, of course. RODEO still owes me a weekend drive on account of all of my pro bono legal representation I did to get him out of trouble over at Miata.net. :smash:
 

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You all can test drive mine when I'm out testing a Sol, otherwise I'm too busy smiling :lol:

Anyone care to field 2kwk4u's original question, is a s/c better than a turbo, as turbos generally have a lag, or have todays turbos improved? Seems the MSM factory set up explains that turbo lag, but how about for the Sol?

RODEO
 

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The issue of turbo lag is one that rages on and on with the Miata guys. The turbo setup that Mazda went with is a bit on the tame side when you consider what can and has been done aftermarket for quite a few years. For that reason, the aftermarket crowd b-tches on and on about it. Usually, they're the guys that spent more than I did for a late model Miata than I did for the MSM. Besides the turbo, the MSM has a much better suspension set-up.

There was an article out some time back that quoted one of the Mazda engineers out of Japan as saying something like this, "We didn't want a car that no longer felt like a Miata. We tried several different combinations that gave us over 200 HP. Our concern was that the average driver would wind up going backwards off the side of the road. We didn't want a mini-Mustang."

Interesting thoughts.

My MSM's turbo has smoothed out with 5K miles. However, depending on how I catch the throttle, there is a bit of lag...but not much. This isn't a supercharger afterall.

But I tend to drive (when I'm out for a fun drive) with the RPMs over 4000 so having the turbo spooled is never a problem. One thing I found is that when I'm going down the highway at 75 mph, getting to 100 mph+ is quickly done by just stepping on the gas. That's not something a non-Turbo'd Miata ever did before, you'd have to downshift.

But yes, there is some lag. It's not much, and most can be eliminated once you've learned the car and what RPMs it prefers. It's a matter of preference really.

And yes, I contributed to that thread on miata.net that was linked here. :)
 

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Matt123 said:
There was an article out some time back that quoted one of the Mazda engineers out of Japan as saying something like this, "We didn't want a car that no longer felt like a Miata. We tried several different combinations that gave us over 200 HP. Our concern was that the average driver would wind up going backwards off the side of the road.
Well put, it worked, I haven't spun out of control yet!

I was having some fun on the wet parking lots last night, found one turn that was perfect, did it 15 times or so, beautiful throttle overstearing FUN.

Anyone want to tackle the Supercharge end of the question, I need some education on s/c enigines?
 

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Discussion Starter #19 (Edited)
RODEO said:
Anyone want to tackle the Supercharge end of the question, I need some education on s/c enigines?
Well, the thing is we've debated t/c vs. s/c here a few times already, and that wasn't the direction I wanted to take with this thread. But since you're asking...

Here's what I know about roots-type blowers (the kind that sits right no top of your intake manifold, vice a CSC which is basically a belt-driven turbocharger, though some of this is universal).

As soon as the engine is spinning, the s/c is spinning. Since it's belt driven, increases and decreases in blower RPM and thus boost (up to max boost depending on the application) happen simultaneuosly with changes in engine RPM. From my understanding, this is why there is a night-and-day difference in lag between the two forced-induction methods.

Under normal driving conditions, the boost bypass valve is open, so the S/C is just recirculating air within itsself rather than cramming it into the intake manifold. As soon as you goose the throttle, or the load on the engine increases, the ECM will tell the boost bypass valve to close, and *voila* instant boost!

If you want to increase your boost potential, it's a simple matter of putting a smaller pulley on the supercharger or, conversely, a larger pulley on the crankshaft.

The biggest perceived drawback to supercharging is that it takes power to make power. In otherwords, there are some parasitic HP losses associated with spinning that supercharger, whereas turbos harness the otherwise wasted energy from exhaust pressure.

Edit: let me append this by putting down what little I think I know about centrifugal superchargers (CSC). Generally speaking, a roots-type blower will displace a larger volume of air per revolution. That's why they'll make power down low and give you a nice broad torque spread. CSC's, on the other hand, move less air per revolution, but generally spin at a much higher rate. From my understanding, they don't just spin at pulley RPM, but they have an internal gear drive that causes the blower to spin MUCH faster. Therefore, at lower engine RPM they are moving less air than roots-type blowers, but they actually move alot MORE air at higher RPM, and thus they act more like turbochargers. You're not necessarily sacrificing low RPM power, you're just not getting as much help down low. The tradeoff is more horsepower.

Any corrections? Anyone?
 

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You're right 2kwk4u, looks like you wanted to know of the MSM has an unusual amount of lag if I'm correct? And I think we got the anwser, yes, and it is setup that way by the maker intentionally, but can be modified to reduce lag. Sound about right?

If so, and the answer is done, how about comparing your notes on s/c to what you know about t/c, IOW another couple of pararaghs to educate me on the t/c (since you did such a nice job on the s/c). I'll use it to learn about t/c's, and possibly apply it to boost controller one day.

thanks
RODEO
 
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