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Thank me later only if/when you’re satisfied with how the car handles! Now onto playing with the prop valve next. I think you’re gonna be stoked with the car given all the work you’ve put in haha.
Regarding the bridge bolt/nuts galling, I had one on my BX11.75 Wilwood kit do the same thing as well. Maybe the same bolt supplier or something? I actually uninstalled and reinstalled the nut a couple times because it felt like I must have been crossthreading it at first. Weird.
Ha.. well if the car handles like poo that's not your fault, at least I have a reasonable expectation of HOW the adjustments should work so that's good. I was told by the previous owner who installed the coilovers that they're pretty old so I'm sure they've had better days but it is what it is. For the record I got the racing beat 54103 1.125x.188 wall swaybar for the front which I think is the medium thickness bar (maybe shoulda got the bigger one) and the SM rear swaybar. Both bars are set at full stiiff.
Weather is looking cruddy for tmw (cold and wet) but this is typical east coast weather this time of year. Either way I'll have fun sliding it around and getting it setup.
Interested to see where you land with the sway bars. I have a big RB 1.25” sway bar in the soft position and a stock bar in the rear. And my car is a little bit on the oversteery side at low speeds where the aero isn’t doing as much work. Dunno how big bar/soft position compares to med bar/stuff position, but I’d imagine your car would be much more oversteery than mine with the stuff bar in the rear. Interested in hearing your thoughts after this weekend, although with the weather I’m sure you’ll be sliding around a bunch regardless lol.
Looking forward to the updates! Doesn’t sound like great testing weather but should still be a bunch of fun. I feel like I’ve learned more about vehicle handling during wet track days than anywhere else lol.
Well, car made it back in one piece so it was a successful weekend on track. First day sucked weather wise. Cold and wet blows but I made the most of it. First off setup. Appreciate your input Zak, based off of what you said, I set the front coilovers to 18 clicks from full soft for the front and 12 from full soft for the rear. I didn't know what to expect but I ended up leaving them that way the whole weekend.
So early Saturday was nasty. Steady rain and highs in the upper 30's. By the afternoon it cleared up and was then just cold and windy. Here's a shot from the morning.
For those not familiar. Summit point has 3 tracks. Shenandoah is one of them and some people refer to it as a giant auto-x course because there are a lot of turns. I've been on it 10+ days so I am very familiar w/ it and it's a fun track. There's a karousel in it which is very hard on cars but a lot of fun. Many of the turns are actually off camber so lines through turns are not traditional where you want to stay far to track right or left before turn in. In many turns you have to turn in early to avoid parts of the off camber sections. First session was literally just an ice skating rink with pools and puddles everywhere. 2nd session wasn't much better but the rain stopped at least and the track was wet so I could see a little better how the car felt. Suspension wise the car felt good so I didn't touch the suspension settings. Here's the track layout.
On the 3rd session of the day I was finally able to push the car a bit and got some heat in the brakes. Towards the end of the 3rd session I noticed the car seemed like it wouldn't accelerate or was struggling bad. Letting off the throttle I could hear the brake pads screeching so thought ****.. let me just limp back to the pits and see what's up. My first thought was a stuck/seized rear caliper. Unfortunately, as the brakes dragged more the friction increased and the resistance got higher so I couldn't even make it back to the pits. At least it was towards the end of the session and they black flagged everyone in. After the car sat for a few minutes the brakes cooled a bit (and perhaps the pressure on the pads did as well) I was able to put it in first and putz back to the paddock. Here the car was stuck on big bend.
Getting back to the paddock we noticed both front wheels were very hard to turn so it wasn't just one caliper. Basically the line was holding pressure against the caliper pistons which meant it was either the MC or something with the prop valve possibly. The pedal was SUPER stiff and there was no play so I thought that maybe removing a lot of the free play in the shaft was a bad thing. I loosened the 14mm locknut, and added back about 1/4" of play in the MC rod. Long story short that fixed it for the rest of the weekend. I'm thinking that as the fluid heats up maybe the slack in the MC rod gets taken up so it needs that free play. With most of the free play removed the pressure has no where to go and it applies force to the brakes. So, do NOT remove too much free play from the MC rod. The brake pads I'm running are pfc 11/97's f/r and I ended up with 6 full turns from fully open on the prop valve. I'll say I love these pfc pads. Very easy to modulate, lots of bite, their only downside is they are loud as hell and screech.
Other things regarding the car later on day 1 I was rubbing pretty good in the karousel. I don't mind fender liner rubbing, that's no big deal, but it was rubbing a bit on the metal fender bumper tabs. The suspension also settled a 1/4" on the front passenger side again (the karousel will probably get any stiction out of any bushings). I ended up cutting a tiny bit of the metal fender and bumper tabs off at home day 2 before heading to the track and raising the right front up again 1/4". That solved the rubbing issue in the karousel. While I had the wheel off I checked the Afco F88 caliper. The sleeve spins freely. The instructions say to torque the bridge bolt down until the sleeve stops spinning but there's no way I could without snapping that bolt. Ultimately not a big deal but just a heads up for anyone else.
Day 2 was sunny and got better as the day went on. I missed my morning session as I was tinkering with the car but it was in the upper 20's and I figured I wouldn't miss much. Of course like many track days my gopro missed the last session and last half of my 2nd to last session so it missed my fast times which sucks. My best time for the day I ran a 1:47.7 and I missed fourth on that lap so that's worth a few tenths maybe.
Some observations.. I'm running 245 square Nexen Nfera sport R's. The highs of the day Sunday were 47 degrees but it was sunny. These tires took several laps (probably 3) to get upto a good temp and honestly I think they just got better and better into each session. It just took a while to get heat into the tires on a cold day with only 140hp crank. As the day went on and it got warmer I realized the tires kept getting more grip with heat and I could've definitely pushed my braking zones and carried more speed through turns. Honestly the suspension felt fairly neutral. Trail braking it was easy to get the car to rotate and I didn't really notice any understeer either. Coming from an s2000 it feels a lot like a baby s2000. Little lighter, nimbler, and less power. Brakes were great, no complaints at all. A couple times I locked them up in the braking zones a bit but it wasn't hard to modulate at all. Steering no issue. I'm used to having to make quick corrections and when I trail braked a bit too much into a turn it was easy to catch with some countersteer.
So for the bad/issues. The car needs more powa. I also noticed in the later sessions Sunday when WOT after apex on a couple turns the tach would bounce a bit like the clutch was slipping. Keep in mind the tach didn't jump a lot, but more like a blip where the rpms would jump 500-1k rpms for a split second then go back down. Now, I want to rule out a slipping clutch since it's brand new and way below the power threshold so it makes me wonder if I was getting inside wheelspin and maybe I don't have a closed diff/torsen? I thought I did but maybe not..? Is there an easy check for this? I know torsens when unloaded can act like an open diff but I wasn't hopping curbs when I noticed the revs jump a bit. I also tried a session on the skidpad and it didn't feel like I was spinning both rear wheels at times.. My driving was not great as I was quite rusty.. I missed forth a bunch in turns and I was definitely being a bit of a pu**y not chucking the car into a couple turns a bit harder. Just have to get used to the car and need more seat time. Finally, at the end of the day it looks like I have the dreaded junk2 TB hang now. It didn't do it till I was ready to go home, but now the rpms will sit at 1500 or 2k rpms. I manually actuated the throttle rotor and it feels like there's a bit of resistance/friction now and it's not as smooth. Not sure what's up with that but I'm sure that's contributing to the sticking.
I'm happy with the car and had a lot of fun. I tried to get Miguel to take it for a spin to let me know what he thought (he's got the Mustang and runs a 1:38 on Shenandoah for comparison, but he and the car are fast) but maybe next time. He's used to power so when I took him for a ridealong for a session he laughed when I said I'm giving it full throttle.. lol The car definitely could've done a 1:46 or better. Suspension isn't terrible. I could definitely see how a good suspension would help but the BC's did alright. Not really sure what I'm going to do with it next. Probably let it sit for a week then decide if I want to start wrenching again.
Does anyone use any phone app lap timers? I've used Racechrono pro in the past and while an AIM would obviously be ideal maybe the data from this isn't too bad. My phone wasn't hard mounted so the G data isn't accurate. I use a Qstarz 818xt external gps running at 5hz that connects via bluetooth.
I don't have many good videos but I'll post a few vids in another post. If you made it this far and read all that thanks.
I use the phone internal GPS as well. What I've heard is that it's good enough for overall lap times, but don't bother trying to read into sector times or even corner by corner analysis.
I know you said the brakes worked really well, but I had a complaint about my DIY Afco setup and am wondering if anyone else has it with the off the shelf kits:The pedal is firm but it's not as consistent in height as I remember it felt with the stock brakes last year. My caliper is really well mounted and there shouldn't be any flex there, or in the caliper itself. I'd never had to give the brakes a tap on the straightaway before, and yesterday at VIR I was doing it into every major braking zone in order to keep the pedal consistent and high. Maybe I'm feeling the result of the spindle itself flex?
I use the phone internal GPS as well. What I've heard is that it's good enough for overall lap times, but don't bother trying to read into sector times or even corner by corner analysis.
I stopped using the internal phone GPS because I was having issues with it missing starts/stops and use an external gps unit. The stock internal gps runs at 1hz whereas the external runs at 5hz and uses DBAS I believe, so it should definitely be more accurate but hard to say how accurate. I would think the G sensor and circle should be ok with a solid mount but honestly don't know.
I know you said the brakes worked really well, but I had a complaint about my DIY Afco setup and am wondering if anyone else has it with the off the shelf kits:The pedal is firm but it's not as consistent in height as I remember it felt with the stock brakes last year. My caliper is really well mounted and there shouldn't be any flex there, or in the caliper itself. I'd never had to give the brakes a tap on the straightaway before, and yesterday at VIR I was doing it into every major braking zone in order to keep the pedal consistent and high. Maybe I'm feeling the result of the spindle itself flex?
I definitely didn't experience that this weekend. I'm not sure what conditions led to that in your setup (long sweepers?). There's only one longish sweeper on Shenandoah and it's not too long (finishes top of 3rd). Brakes were always consistent when I went to go for them fortunately.
Here's a video from Sunday. It sucks I didn't catch the last session but you can see the revs climbing a bit at about 30-31 seconds in. The revs climb about 500rpm and then it "catches." Maybe that's just how the torsen works? Not a big deal but just something I noticed. Any thoughts are appreciated.
Solid weekend recap, man! Stoked to see the suspension worked as desired! Looks like you got a little bit of everything, from weather to minor mechanicals haha. Wet track days are fun… for a bit. Glad the sun came out for you guys on Sunday though.
Good to see you figured out the booster pushrod adjustment issue quickly. I had mine adjusted for minimal free play like yours at first, but figured there should be a little bit of dead play in the pedal for when everything heats up. Guess that answers that haha.
Finally got around to washing the car and swapping the pads to street pads. I set the wilwood prop valve to 8 turns from fully open which makes the brakes feel much better on the street and more front bias. I drove the car and the TB hangs like a sumabitch now. Almost everytime gently letting off the throttle it'll cause it to hang.. damn junk2. As I mentioned before it has a noticeable squeak now when operating the throttle plate and I feel a bit of friction. Crap like this is what drives me nuts with aftermarket parts sometimes. I don't want to waste a lot of time screwing with this TB. I could try to get junk2 to send me another one but from what folks have said they're no better. We'll see.. Next plan of action is getting the BMM ECU working. I have to install the FF640's and DW200 pump so I'll probably mess with the junk2 TB while I'm swapping injectors. Car is clean again. I had a minor 4 off at the last track day and got a bit of mud down one side so needed to clean that off. Also i like the wheels silver. Meguiar's heavy duty wheel cleaner works wonders for cleaning brake dust.
Another thing after the track weekend I noticed is the clutch pedal clicks. Seems a common problem and the stopper broke. Ordered a new one:
Finally.. the plan for the BMM Ecu is installing a 36-1 trigger wheel, fuel pressure transducer, oil pressure transducer (this will probably go in with the turbo), oil temp sensor, and 3 port mac solenoid for boost control. It has a built in wideband controller so that'll go in of course. Once I get the car running on the BMM ECU I'll install the kraken kit. I will try to document a lot of steps of the BMM install since there isn't too much info out there.
One question for you guys on the kraken kit.. did you need to port the wastegate port at all on the 2560 turbo? I thought I recall someone mentioning that they did it due to boost creep but not sure. Also the clutch chatter is still present and annoying as it seems to cause the whole drivetrain to shake/shudder. Is the drivetrain "shudder" on this car much worse simply due to the design of the PPF and no transmission mounts? It would make sense to me and it seems to be a common problem and complaint. It's much worse in reverse I just have to slip the clutch a little higher.
I can't remember, did you drill another hole in the throttle cam to preload the return spring a little more on your TB? I ended up drilling mine only 3mm or so past the stock hole and that solved the throttle hang for me for good. I ended up spraying a little bit of penetrating oil into the surface that the cam pivots on and that seemed to stop any squeaks that it was producing. Can't quite picture it in my head right now though... it was almost a year ago that I did it.
In reference to the wastegate, I didn't port mine. I ran the stock 8psi wastegate with a couple spacers to bump it up to 9pai. On my stock motor, it crept from 9psi up to 10 from ~5,700rpm to redline. With my built motor, it would creep a from 9psi to 11 at redline. It doesn't seem to creep at all on e85, I'm assuming because of the more advanced ignition timing spooling the turbo less. I never felt a need to alleviate the small amount of creep. As soon as I set up EBC and turned up the boost, the creep became irrelevant.
What clutch are you running again? I'm sorry, having trouble remembering everyone's setups with all the build threads I'm following now lol.
I can't remember, did you drill another hole in the throttle cam to preload the return spring a little more on your TB? I ended up drilling mine only 3mm or so past the stock hole and that solved the throttle hang for me for good. I ended up spraying a little bit of penetrating oil into the surface that the cam pivots on and that seemed to stop any squeaks that it was producing. Can't quite picture it in my head right now though... it was almost a year ago that I did it.
Yes I followed OptionXII's instructions to the T, and drilled the hole in the exact same as his. I've googled the issue a bit and seems semi-common for people to have to drill the hole and require more tension to avoid the throttle hang. I will mess with it next time the TB is off.
In reference to the wastegate, I didn't port mine. I ran the stock 8psi wastegate with a couple spacers to bump it up to 9pai. On my stock motor, it crept from 9psi up to 10 from ~5,700rpm to redline. With my built motor, it would creep a from 9psi to 11 at redline. It doesn't seem to creep at all on e85, I'm assuming because of the more advanced ignition timing spooling the turbo less. I never felt a need to alleviate the small amount of creep. As soon as I set up EBC and turned up the boost, the creep became irrelevant.
What clutch are you running again? I'm sorry, having trouble remembering everyone's setups with all the build threads I'm following now lol.
Thanks appreciate that info that's good to know. I probably won't bother porting mine either then. Creeping to 10psi is pretty minimal and not bad. I want to be able to keep boost low to preserve the stock motor and tranny for the time being. I'm running the SM clutch and installed a new ACT prolite flywheel. Both were brand new and I was very careful to keep the surfaces clean and install it properly. A little chatter isn't bad as much as it's just a little annoying. I was thinking because the tranny doesn't have its own mount any chatter gets magnified in this car and translates into drivetrain movement/shudder. I just gotta slip it a little higher..
Ok ok, we’re on the same page then haha. I’m running the SM clutch with ACT ProLite flywheel on my car as well. Did you go full face or 4 puck for the clutch disc? I’m running the SM 4 puck in mine and it chatters a decent bit (no shade thrown to SM, I know it comes with the design). You’ll get used to it, there’s a very finite amount of throttle vs clutch pedal depression that gets the car moving without a fuss.
Ok ok, we’re on the same page then haha. I’m running the SM clutch with ACT ProLite flywheel on my car as well. Did you go full face or 4 puck for the clutch disc? I’m running the SM 4 puck in mine and it chatters a decent bit (no shade thrown to SM, I know it comes with the design). You’ll get used to it, there’s a very finite amount of throttle vs clutch pedal depression that gets the car moving without a fuss.
I'm just running the full face sprung disc. I wanted to keep stock engagement/no chatter but it is what it is. Not a big deal. Seems like clutch chatter is a problem for miatas.. not sure what exactly causes it.
So I wanted to report back about my issue with the skunk2 TB.. I tinkered with it yesterday, reassembled it, and now it doesn't hang (only drove it yesterday so we'll see after time). Cliff notes is that it's something with the bushing/spring that is causing the friction. I won't retype it all link here: https://www.miataturbo.net/engine-pe...7/#post1648804
I did initially try to drill a stiffer hole and F'd it up a bit (just a bit to the inside) which I think was causing the spring to bind when the nut is tightened down so I just reused the old hole and it felt smooth on reassembly. I also hit the spring with some silicone lube. We'll see what happens. Hopefully it's fixed but I'm not holding my breath.
I believe I ran into the same concern as you when I first installed my throttle body. Tiny bit of friction on the bushing that was solved with spray lube (can’t remember what I used). In my case, I don’t believe the friction was causing the rev hang issue. Additional spring preload solved that.
My TB always felt drag-free while cold and then would incur the rev hang issue after getting up to temp. Something expanding and binding just enough once it got hot obviously…
I believe I ran into the same concern as you when I first installed my throttle body. Tiny bit of friction on the bushing that was solved with spray lube (can’t remember what I used). In my case, I don’t believe the friction was causing the rev hang issue. Additional spring preload solved that.
My TB always felt drag-free while cold and then would incur the rev hang issue after getting up to temp. Something expanding and binding just enough once it got hot obviously…
Do you remember how much additional spring preload you have? I should've clarified above I'm using the same/similar hole position that OptionXII suggested in his skunk2 thread. I tried to drill an even stiffer position and messed it up a bit so went back to the "OptionXII preload position."
After sleeping on it and thinking some more.. I wonder if the bushing is binding on the inside as it spins on the shaft? It would make sense that friction might increase as it heats up and since the bushings inner diameter is much larger than the shaft there will be play in it.. I only sprayed some lube on the outside of the bushing and the spring but maybe I need some grease on the inside of the bushing and around the throttle plate shaft...? I also have to wonder why the inner diameter of the bushing is so much larger than the shaft.. Regardless if the bushing is spinning (I'm not sure it is but I think so) it probably needs grease. Here's a picture of what I'm talking about regarding the bushing.
Edit: Just another thought.. maybe the main issue is that the bushings inner diameter is too large? A lot of force is exerted on the bushing with the spring loaded and being too large it can't evenly distribute the force which results in the friction/binding? As noted in the other thread, there is no friction or issue with the throttle shaft and main bushings so this part is likely causing all the problems..
Ah, ok. I misunderstood your previous post and thought you reverted to the stock spring hole. Mine should be drilled out close to where yours is. IIRC, I drilled mine 3-4mm further than the original hole.
I believe my bushing is the same as yours. Can confirm tonight and see if it still has any lube on it from when I tore apart/installed the TB a year ago.
I believe my bushing is the same as yours. Can confirm tonight and see if it still has any lube on it from when I tore apart/installed the TB a year ago.
Thanks man but all good. You can't see the bushing without removing the nut and taking it apart. Definitely don't do that on my behalf as it'll start sticking after that.. Did you apply lube on the inside or outside of the bushing?
Alright fair enough haha. I lubed the whole damn bushing. IIRC, it was when I installed my S2 manifold at the same time and the shop doors were about to close. Was more of a shoot from the hip maneuver than a surgical diagnosis I think I used a little bit of screwloose on it. Never gave me an issue after so I circled back around to it.
The bushing is mostly there to sit inside the spring and help it hold shape. I wouldn't worry about it being too large on the throttle shaft. Don't look at what anyone else does for spring tension, just look at your TPS. If you gently give it a couple %TPS and it stays when you let off, it needs more tension. Once this problem is gone, adding more spring tension doesn't achieve anything.
If there's binding, take everything apart, remove the spring, and reassemble, check for binding. That'll eliminate any issues with the spring, and you can feel exactly where the binding is.
The bushing is mostly there to sit inside the spring and help it hold shape. I wouldn't worry about it being too large on the throttle shaft. Don't look at what anyone else does for spring tension, just look at your TPS. If you gently give it a couple %TPS and it stays when you let off, it needs more tension. Once this problem is gone, adding more spring tension doesn't achieve anything.
If there's binding, take everything apart, remove the spring, and reassemble, check for binding. That'll eliminate any issues with the spring, and you can feel exactly where the binding is.
I drove the car for 45 mins yesterday and no binding whatsoever after I reassembled it. At this point I'll just have to watch it carefully. I'm thinking the last track weekend where the nut backed off a bit maybe allowed the spring/bushing to move a bit and cause binding..? Hard to say. On the street it doesn't look like an issue since it isn't stressed too much and weather is still cool. If it acts up again it'll likely be on track where it sees a whole lot of cycles and heat. Once I get the aftermarket ECU installed it'll be easier to watch/track the issue. I didn't want to just go throw a whole lot of tension on the spring as it'll obviously be more likely to break. Appreciate the advice!
03-22-2024, 09:38 AM
Now onto playing with the prop valve next. I think you’re gonna be stoked with the car given all the work you’ve put in haha.
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I also noticed in the later sessions Sunday when WOT after apex on a couple turns the tach would bounce a bit like the clutch was slipping. Keep in mind the tach didn't jump a lot, but more like a blip where the rpms would jump 500-1k rpms for a split second then go back down. Now, I want to rule out a slipping clutch since it's brand new and way below the power threshold so it makes me wonder if I was getting inside wheelspin and maybe I don't have a closed diff/torsen? I thought I did but maybe not..? Is there an easy check for this? I know torsens when unloaded can act like an open diff but I wasn't hopping curbs when I noticed the revs jump a bit. I also tried a session on the skidpad and it didn't feel like I was spinning both rear wheels at times.. My driving was not great as I was quite rusty.. I missed forth a bunch in turns and I was definitely being a bit of a pu**y not chucking the car into a couple turns a bit harder. Just have to get used to the car and need more seat time. Finally, at the end of the day it looks like I have the dreaded junk2 TB hang now. It didn't do it till I was ready to go home, but now the rpms will sit at 1500 or 2k rpms. I manually actuated the throttle rotor and it feels like there's a bit of resistance/friction now and it's not as smooth. Not sure what's up with that but I'm sure that's contributing to the sticking.
