patsmx5

iTrader: (16)

I don't know if you'll be interested, but way back I used to use a regular ball/spring MBC and they're good, but they crack open a bit early as you know. I started using an actual air pressure regulator instead, one that's rated for low pressures (had to order it online). I think it's adjustable 0-30 PSI IIRC the one I have. Anyways that ****** doesn't crack at all until you hit target. Boost just built up to target and then BAMMM Flat line. But then I turned it up to 28 PSI and it woudl build, hit 28 for about 500 RPM, and then choke/suck the comp wheel into the housing until redline where it dropped to 20 PSI.

But yeah if you're setup isn't hitting choke flow, you can get very damn good boost control from one of these regulators. Also they literally have a big easy to adjust, and lock, **** on top. On mine I think it was 1 turn/PSI, made adjusting boost very easy.

Also your car with you in it weighs less than mine without me in it = I hate you!

Leafy

iTrader: (1)

I think I have an air regulator kicking around just like that, but I need the ebc to flatten the torque curve. The programmed in boost curve goes up to 12, down to 10 and then up to 14, because 5 speed.

patsmx5

iTrader: (16)

Oh and I used this with the EFR 7670 and it held boost flat, like within 2-3 kpa flat! They work and are way less headache than EBC from what I've read online. MBC you set it and forget it.

patsmx5

iTrader: (16)

Ahh, then carry on! Makes sense. Does that ECU do closed loop EBC?

Leafy

iTrader: (1)

Yes. When you used closed loop AEM wants you to set the whole duty cycle table to 50% and then use a couple trim tables and ****. I was trying to actually tune the duty cycle table and then just enable closed loop on that and I guess it doesnt like that.

Leafy

iTrader: (1)

Well that was an interesting boost control issue. The normal hose to the wastegate was torn, which would normally mean ALLOFIT, but thanks to the massive flapper on the efr wastegate and my 7psi wastegate can that only meant like 13 something psi but it also means that the boost I was getting since I've run this motor was basically at best what was on that dyno. Now that I have the 4 port boost solenoid maybe I can actually tune the damn car to do it properly. Well then, you mean this turbo is supposed to have less lag than this? Somehow? Thats possible?

Leafy

iTrader: (1)

Quick post race recap. Wow the car is faster with boost, but I really really need to increase the wastegate preload so I can build even more. New spring rates seem like they were the way to go, much less jarring on mid corner bumps and it was kind of loose on the crap tires which means its probably going to be a lot closer to neutral but still understeery on stickers. I cant actually say for certain that the new springs are better because solo storm thinks I was braking as 1.4g while parked and the lat acc plot also makes no sense, and of course I was on tires from 2-4 sets of tires that were all pretty shitty.

And driving wise I drove worse than normal and coned every run, if I was having even an average driving day I would have easily trophied maybe won he class against last years SMFL champion driving Panda (who also beat last years SMF 2nd place who was driving the SMF car that both of them drove at nats).

patsmx5

iTrader: (16)

Awesome! What's the boost curve look like now?

Leafy

iTrader: (1)

It builds 7psi at 4k and not 5 and it to 12psi target boost by 5k and actually does do the slope up to 14psi between 7k and 8500. But I literally run the boost solenoid at static to get that output so I might as well just connect the boost reference to the line that holds the wastegate closed and run no solenoid. I need to cut my actuator extender so I can get more preload though which is why I didnt do it this weekend. What I really need is a 2 port IWG actuator with a larger diameter piston and matching stronger spring that would still result in a 7psi can but provide more resistance to the exhaust pressure blowing the MASSIVE EFR IWG flapper open. Or... I could just wait until I need to build a new manifold and get a new 6758 with the aluminum bearing housing and a vband turbine housing and just run an EWG and sell this efr.

Leafy

iTrader: (1)

I feel like a real turbo miata now. I broke a tranny. 2nd gear has no teeth anymo.

But it made real nice boost with the wasteagate with 4 turns of preload, lol. I actually was driving good too, and still managed to hold on to second in ssm even not taking all my runs. It did help that the panda broke after my 3rd run though. It was a bad day for cars. Panda broke an R200, I broke a 5speed, and a mod car spun a bearing in its big gsxr motor.

18psi

iTrader: (76)

so is it 6sp and man-boost time?

Leafy

iTrader: (1)

For now I'm throwing in another 5 speed. I have a better solution that I'll be implementing this off season.

Leafy

iTrader: (1)

Well this weekend sucked.

I got out of work at 2 on thursday to go home and do the tranny. I tried my damdest to do the bottom method and after a few hours of struggling with bolts that wouldnt loosen I just pulled the motor at like 7. And of course there were other issues. I got the VVT wire trapped between the intake manifold and the fuel rail, and had to pull the upper intake off with the engine like half way out. The gas gauge decided to stop working at some point before thursday but I think it started working again on sunday morning. It took like a half an hour to get the hood to lined up okayenough to latch. I had to use the acetylene torch on the fill plug of the spare tranny and I had taken the whole exhaust out because I was trying to do the tranny and that took forever to align with dad only having 1 working arm. Oh and the nuts fell off the wastegate actuator somewhere on course last weekend and of course they're 1/4-28 so I had to cut a female rod end in half to get a "nut" for it. Which is what you do at 10:30pm and you only have metric hardware. So about 1am I got it on the trailer, and got up at 4:30 to drive to my codrivers house to then load the car onto his enclosed trailer for the trip down to jersey.

Bought some sweet 10.8lb 15x9.5 keizers with some 40 run but 2011 A6s on them for cheap. Turns out they were 6.75ish backspace and not 6.5ish backspace so I almost corded one of them when I ran them saturday morning. For the afternoon I put the sticker A7s on and went to do my first run in the afternoon and had a couple bits of crappyness getting the mold release off and then the power steering started cutting out after braking. I was worried they were rubbing that bad that it was hard to steer, but then the PS died completely by the slalom and I figured the circuit breaker popped because the A7s were just too much grip. I get in the next staging lane and notice some fluid mist on the windshield and someone starts to yell that I'm leaking so I pull off and shut off the pump. Turns out the banjo bolt on the rack loosened up so I pulled the turbo to IC pipe and tightened that up and threw some random cheapo ATF into the system and bled it and got the car back together fast enough for my two co drivers to take their runs. I lost all of mine.

And after loosing all those runs I ended up dead last in the class going into sunday so I'd run 2nd. 1st codriver does his runs fine picks up some time, I go to do my first run. Launch it like the best launch of all time ever, shift on sound like usual the shift seemed early, and still redlinned 2nd. No drive in any of the gears, I pulled off course. I figured it was an axle, no such luck. I'm not sure what it is yet. I'm guessing diff. I cant be making all that much power, the boost cut is set to 20psi and I'm only targeting 12-14, and the car gets to the first turn at about the same time as the joefis car which is running a stock long block and 2554.

So I just dropped like $2xx in the last few hours buying tools, bearings, solid pinion spacer, seals, etc for the diff rebuild and once I confirm its the diff I'll head to my friendly local miata parts hoarder and pick out my new R&P. I really hope it didnt lunch the torsen. When I'm less tired and less depressed I might pull video.

patsmx5

iTrader: (16)

Torsen probably broke, it's weaker than the R&P. Both are probably toast though.

If it's any consolation, I broke a piston in half a couple weeks ago....

Regarding the diff, if it's only for racing, set it up tighter than spec by about .001" or so. Will make more noise, and wear out sooner, but will be stronger.

Leafy

iTrader: (1)

Savington

iTrader: (31)

Diffs usually make a lot of noise when they go pop. Check your CV joints

Mobius

iTrader: (2)

I can't think of anyone that has actually broken a diff from power. Especially power through a 5 speed.

TNTUBA

iTrader: (1)

Holy Wheel hop!!!! That's what's killing your drive-train parts.

My first Launch sequence starts at 3:10 in this video.



You've got to fix your wheel hop issues or your better carry spare diffs, transmissions, driveshafts and axles everywhere you go.

Leafy

iTrader: (1)

I wish it was that easy. If it was an axle I'd have thrown my spare in on site and my 3rd driver would have been able to run. So with the tranny in neutral one wheel spins easy and the other wheel and driveshaft dont spin. The other wheel spins kind of hard and binds sometimes but the driveshaft spins and the other wheel doesnt. I'm pretty sure I turned the torsen gears into really small bits of metal.

On order I have my own 7-8in mics, a full set of diff bearings and seals, crush sleeve eliminator, and some rx7 delrin diff mount bushings. The delrin bits will hopefully take care of a lot of that wheel hop.

But if I did nuke the torsen like I think its decision time. Do I grab another local torsen with 4.10's fr $500ish and just slam it in there with the delrin bushings. Or do I drop the $700 on the Mfactory Helical that they rate for 1k hp and have a lifetime warranty on, and just get a free one if I somehow manage to break it again. I'd rather not go to a clutch type and have to constantly fiddle with it. Though thats not to say if a good deal on an mfactor metal plate or a cusco type RS came along I wouldnt consider it.

Breaking the gears in the torsen isnt too uncommon, Joe/Charles broke the gears in one with 150ish hp at the jersey pro last year, and I know of a bunch that have eaten the dust with stock short block power at the drag strip without wheel hop. My own wheel hop does have a good amount of; holy crap jersey rubbered in a ton, and not being able to cut good consistant lights while slipping the clutch. I think I need to get the car put back together and find my way to a friday night grudge night before the next pro so I can figure out this tree thing. Hopefully I can actually get some form of launch control setup into the car as well.

Savington

iTrader: (31)

My understanding of wheelhop, as a road racer, is the IRS (specifically the upper control arm) twisting, allowing the top of the spindle to rotate forward. Eventually the tire loses grip, the spindle rotates backwards and violently re-grips the ground. I just don't see a delrin diff mount or even delrin control arm bushings totally eradicating the wheelhop. Learning to launch the car better would help, but I would start by adding an additional link to support the top of the spindle fore-aft (as much as allowed by the limitation of the tire).

Or, none of that, because I don't understand wheelhop as well as I think I do, maybe. Drag racers, learn me something