Greddy "Feel"
 

Hey guys


I've been lurking here for a while and am really starting to plan on getting a Greddy turbo. The main thing holding me back is not knowing how the turbo kit feels.

I rode in a Mazdaspeed NB with a modded turbo, and though it had a lot of power (somewhere around 170), it felt overly peaky. I don't know if it just had a slow spoolup or what, but the car would start slowly and then give a tremendous jerk when the turbo finally kicked fully in. I did NOT like that feel.

I have a 92, and I'm wondering if the turbo feels smooth. If so, I'll probably get one. I had a turbo Supra and it was nothing like the Mazdaspeed I rode in, it was waaay smoother.

Thanks for any responses :)

Well i hate to disapoint you but a greddy wont be as sedate as a turbo supra. There is a reason that the power took a dramatic upswing on the miata it is becouse we weight 1K lbs less than said supra so every HP and lbft helps that modded turbo NB you rode in is somewhere akin to a 300 someodd whp supra. If you want no power surges then go SC my turbo is linear and so is the greddy but we still surge up torque in the midrange this makes us fast. if tuned right this surge doesnt end though. I like to keep myself pinned in the seat with g forces.

I don't mind SOME surge. When the turbo spooled up in my Supra (hitting about 13.5 psi) there was a good rush of power all the way to redline. However, the NB I was in seemed very sluggish until the turbo spooled almost instantly and slammed you back into your seat. I don't know really how to describe it. Seemed like there was something wrong with the tuning...

That's been a huge complaint about the factory MS NB. I've not ridden in one, but I've driven Greddy kit'd NAs, and they can feel peaky, too. The best you can do to get rid of this is open up the exhaust and get a boost controller on the thing.

You can see the slow boost build of the stock car in this dyno chart comparing it to the NC: http://flyinmiata.com/tech/dyno_runs/NC_vs_MSM.pdf

Although this next graph shows what happens when you throw the whole FM upgrade solution at the MS NB and is way more powerful, you can see they got it to spool much better, too...about 600 RPM sooner to hit 100rwhp!: http://flyinmiata.com/tech/dyno_runs/MSM_big_daddy.pdf

I testdrove a MSM and it didnt feel bad at all. it hit full boost around 3-3.5k (I think, its been a while) and pulled kind of hard all the way until redline. I think your friend has some fuel/timing issues. It sounds kind of like running a GReddy with no engine management and just the timing retarded to 6*. That makes you loose your low end but in boost you are still safe. The car just doesnt feel 'right' until your in boost. Engine management obviously solves this problem.

I think GReddys under 8-9psi have a nice linear power curve, once you start feeding them more boost the power skyrockets.

My friend had one that I drove around for about month, the stock msm have a real gradual kick in for the power, the engineers wanted it to feel like it had a bigger motor, so the power delivery is really gradual. The greddy is all at one time my man. Mine has nothing really, and then all the sudden the thing just takes off with boost. Do your research, there are smoother turbo's out there. There are a ton of people on here with all kinds of different setups, just ask them in the diy section and I am sure that you will get some good responses. That is the path I would take, there are also kits that are almost always for sale that people have put together. I have the emanage, it solves it somewhat, but it still kicks it in the ass real hard at one time and then pulls throughout.

Mine feels pretty laggy... Fairly slow to get going, but once spooled boost feels like opening a jato bottle. Power delivery is more sudden and violent than it is linear. I'm enjoying it a lot, but I also have a v8 daily driver.

You might be happier with an MP62. It won't make quite as much torque compared to a typical turbo, but it's peaking while a turbo is still building.

See, I've always read the MSM had a real slingshot power curve, and this is coming from a lot folks who've never driven a turbo'd car before. Perhaps that's why Steve and Broke didn't find it unusual feeling.

You can clearly see in the stock MSM curve, though, that it doesn't hit full boost/torque until ~4500 RPM. Sounds a lot like a stock-ish Greddy to me.

Oh what the heck. I'll still get one and deal with it. I'm sure I'll manage.

Somebody sell me one quick before I change my mind :D

IMO if your greddy is setup right its just power across the whole band. Mine feels fairly consistant... consistant being that I cant really get traction anywhere on the powerband. I think removing the MAF on a greddy really helps with the spiking issues.

My Greddy setup is fairly non-stock. I'm running a 2.5" exhaust from the turbo flange to the tailpipe, and using a manual boost controller and a piston-type BOV.

Starting off from a standing stop in first, it's fairly sedate until about 4,000RPM, and then it feels like it just suddenly "turns on". From that point, power is there all the time, through all the gears, and it's fairly constant.

If I'm just cruising along in 4'th or 5'th and I hammer the throttle, the power somes on very quickly, but it's very smooth, unlike the first gear "turn-on" which, while not what I'd describe as violent or peaky, is definately a kick in the seat. :D

Comparing my dyno graph to others with big exhaust, I think it shows clearly that the on-off effect lessens when the turbo can breathe. Look at the how the slope of the hp plot increases on the first graph, and note how the slope of the second graph is pretty constant.
https://www.miataturbo.net/forums/at...6&d=1164045446
https://www.miataturbo.net/forums/at...7&d=1159295804

6psi Greddy, Enthuza exhaust:

http://www.rev2red.com/images/cars/d.../phil_plot.jpg

compare that to Toms 15psi above and you can see there is a point where they just love to shoot the torque to the sky.

Why not a lightened flywheel and upgraded clutch to speed things up until the turbo spools up?

Nice a/f. What engine management?

Lightened flywheels are a mixed blessing, especially so with a FI car.

It's Phil's (Mach929) ride. EMB w/autotune.