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in looking at your cooling system tweaks, I'm trying to envision how to utilize them in my car.
where did you place the fans?
would you say that the alternate placement and ducting outcools the factory placement and shrouds?
I'm concerned about keeping temps in check with the engine swap.....
That's the A/C fan, I used it because it was smaller and blocked less air flow. If I knew I wouldn't get stuck in stop and go traffic I wouldn't run a fan at all, the least little bit of speed is enough to cool the car.
After two track weekends and a few thousand street miles I honestly believe the ducting both on the inlet and exit of the radiator is 90% of the reason the car cools so we'll. Laying the radiator down like this and shoe horning in this massive circle track radiator is a ton of work and I just don't think it's the main driver. I think if you're careful you could duct the exit of the radiator with it mounted in stock location out the hood just fine. You could even try just venting the hood without the exit ducting and see how that works first.
Things get complicated when you need to package an intercooler in there too.
For what it's worth, we more or less discovered the same thing with our Pikes Peak M3, both with CFD and in real-world testing - that doing proper ducting in AND out of the radiator and keeping it in the stock location really works about as well as doing a full slant-mount setup. The biggest part that made a difference was making sure the same amount of air that gets IN is able to get OUT, and that the ducting in the hood was far enough forward to still present a low(er) pressure area on top to help extract the air. We also duct down and out the wheel wells.
I've been going back and forth with wanting to do a setup like this on mine, and include the AC condenser as well...but now I'm kind of thinking about just going K series instead of putting all my turbo stuff on, so idk.
Thanks for the data point, I was pretty excited to be able to get the exit ducting as far forward as I did. The pressure maps of the hood I've seen posted show a pretty strong negative pressure zone there.
I always look at cooling as being HP based, weather that's a turbo'd 4 banger or a LSX swap this cooling system would be ready for whatever I come up with.
Eh, it is and it isn't (HP based)...one of the reasons that the BMW turbo powered F1 cars in the mid-late 80's were so much faster than the other cars, in addition to making gobs more horsepower, was because they did it with a turbo 4 cylinder instead of a bigger displacement engine, and they were able to run smaller radiators and side pods, thus giving them a smaller aerodynamic profile down the front straights at high speeds. They did, however, tend to run out of fuel...
We did make a few tweaks for 2015 after the initial CFD runs and the previous race, and modified the hood ducts to expand wider across the front. Originally we had a duct from a GT500 Shelby, which worked great in every test we did except for race day in 2014, hah.
I've come to find that most track/race radiator setups at their core are WAY more than you'd need, if they just had the proper airflow to 'em. It's better to have it and not need it, though
Very cool stuff, I'm assuming a turbo motor needs less cooling capacity because so much of the combustion heat goes out the exhaust?
I had plans to regulate how much air was split between the radiator and intercooler. That way I could make adjustments to get the best IAT numbers but still cool the car. Both temps look excellent but you can never have too much intercooler capacity.
Been a while.......so this winter wasn't anywhere near as productive as last but it always seems like the closer I get to locking down a setup the more time it takes. Plus I got distracted by some pretty blue things. I'm stepping up to 1000/500 spring rates to along with the available damping. Interestingly enough the Hard S bilstein shock dyno curves fall right into the middle of the AFCO adjustment range.
I picked these up for a pretty good deal, one had a bent shaft and they were missing the top hats and springs. Luckily these are easily serviceable so I was able to replace the shaft and rebuild them all right on the bench.
Setting bump stops.
I took the opportunity to go ahead and rebuild the lower control arms.
I would have liked to done mono ***** on the inner pivots but that'll have to wait.
I was / am a huge fan of DIY bilstein setups and had amassed quite an inventory of hard S shocks. I decided to clean them up and blow out my inventory to pay for the AFCO's. Sold 3 sets of these.
With the suspension hopefully improved I turned my attention to the power to weight ratio. I dropped weight from quite a few places, battery, rear bumper supports, a/c condenser, carpet, and the exhaust, but more on the exhaust in a minute.
Overall I found ~75 lbs. in the car, I'll have a more exact number when I corner weight it next weekend. You can read about these tiny little batteries and my other weight saving exploits in this thread. https://www.miataturbo.net/race-prep...-50385/page20/
So the exhaust is an attempt at both weight savings and power increase. More importantly quicker spool. Interestingly enough the lack of throttle response is some what of an annoyance while auto-xing. It's a non concern on track or the street. My down pipe has always been 3" but the exhaust necked down to 2.5" at the "cat". I had always planned on upsizing just never got around to it till now. Overall I can't complain with a full size muffler and the upsize all the while saving 15 lbs. over the 2.5" exhaust. I calculated the aluminum saved me nearly 35 lb's over what a stainless 3" system would weight. More details are here: https://www.miataturbo.net/race-prep...t-76843/page3/
I also pulled the turbo as I was getting some intermittent smoke out the exhaust and I was getting a concerning amount of radial play. Glad I did, cause I found a shattered thrust bushing.
Found this not a second too soon......another few miles and it would have rubbed out the compressor wheel.
I also found where the wastegate actuator bracket had cracked, probably from where I was running it as a dual port.
I had really hoped to build a forged motor this winter, but time was just not on my side. I did a compression check and found 185 psi on all cylinders cold, I also stuck a borescope down the spark plug holes and the pistons look really good. Initially I was worried with the oil consumption increasing but now after seeing the turbo condition I'm pretty sure that's where it was going. I'll keep putting the forged motor together and keep an eye out for a bigger turbo for the next iteration of this setup.
Buttoned up the rest of the suspension with the help of a few friends and got it on the scales today. I was pleasantly surprised to find that I had actually dropped more weight than I had anticipated, mainly because I had forgotten to weight the AFCO's to compare to the bilsteins. That's the only thing I can think of that would account for the additional weight savings.
Before the diet plan:
L. R
626. 629. F
563. 551. R
Total weight: 2369
F/R balance: 53%F
After diet plan:
L. R
617 612 F
491 521 R
Total Weight: 2241
F/R Balance: 54.8%F
Total Savings: 128 lbs. !!!!!!
The F/R balance is something left to be desired, but less weight is better than more weight that is balanced. I was closer to a half tank of fuel on the after weight in and just under 3/4 for the before so 15-20 lb's could be accounted there. I'll still be danger close to 2200 dry which I'm pretty happy with considering it still has power window, cruise and carpet around the driver.
I got the alignment roughed in enough to take it for a spin, unfortunately it was raining. Initial take away......AFCO's are set WAY too stiff and holy chit is this thing a handful in the rain. Boost comes on much quicker now, anything north of 3500 rpm is like the boost is attached to the gas pedal. Even on low boost it was instantly spinning the tires at 60 mph with how fast the boost was coming on, had to put it up before I killed it. Hoping for a break in the weather soon so I can get some data logging done. First auto-x of the year is on March 11th so I have a little time to get it ironed out also going to get to a drag strip and see what this thing actually has. Hoping to get quite a bit (for me) track time this summer as well.
I actually ran the Bilsteins at 1000/450 for a while and it understandably pushed a bit even with the stock front bar and rear bar hooked up.
I've made the first few trips on the AFCO'S on the street and I'm still chasing down a baseline setup, I started stiff and I'm softening them up until if feel the tires stay in contact with the road over the rough stuff. So far they of course ride way worse and overall I feel they provide less grip because I'm bouncing the tires over imperfections rather than absorbing them. Another few adjustment cycles and I'll have a better idea of how they are but there's no reason why I can't find the sweet spot with the adjustment range they have. Once I feel like the car accelerates and brakes well over the rough stuff I can work on tailoring the rebound to get the corner entry behavior I'm after. I've got my first autox event on the 11th so I'll have a better idea of how I like them then.
Just trying to work on the boost control and decided to throw in the camera for a trip around my test loop. Rolling on the throttle or sweeping from below 4k is no problem. Still getting some overshoot if I stab it above 4k but getting better at it. Seems the control algorithm is always a a few tenths of a second behind what's going on.
I also had a somewhat disappointing trip to the drag strip last weekend. My first run of the day was on wastegate spring only because the car didn't get warmed up in time since I got confused on which lanes were going first. Second run was on full boost. I guess I can't be too disappointed but was hoping for quite a bit more MPH at the boost and fuel levels I'm seeing. This was on a set of borrowed 225/50/15 ET streets which stuck.....ridiculously well. The super miata puck clutch is pretty grabby and I was having a hard time slipping it out of the hole, We were at the track for 6 hrs and only got 2 runs, pretty sure with a few more runs I could have gotten it down to a 12.xxxx, still rolling around in my head if that bog at the start would have hurt the MPH.
13.9 @ 102mph on 6psi wastegate only
13.4 @ 105mph on 14psi
Not too bad. I would say that there's probably a 12.9 in that car trapping 105. It sucks when you have to be there all day just for a couple passes, if there's a week night event, that might give you more seat time.
Yeah this was the first real event at Keystone (Pittsburgh) so every drag car in the north east was there. Come to find out later that evening they were having a street car only test and tune which is what we should have been there for. Already had plans so we couldn't stick around. I'll probably go back up in May and try it again. Also found a semi-local dyno, so I need to get the car on the rollers and dial in the timing tables. That might be where some of the power is hiding, also I can get my boost curve dialed in for a true 225 ft/lb plateau.
Finally got back on top with an FTD at a local auto-x. The course is a hot mess with very loose asphalt. I was able to get traction control working pretty decently and that was the magic bullet I needed to be competitive again.
In an effort to get some pad life I upgraded to a relatively cheap Mini turbo rotor and wilwood dynapro caliper setup. My brake ducts seemed to work pretty decent with them too. After two days on track it looks like I'll get 6 days out of them pretty easily which is double the stock sized stuff. Plus pads are 30% cheaper.
Spent memorial day at Mid Ohio with Chin Motorsports. Man this car is fun, other than some aluminum exhaust carnage and an odd miss that came and went it did really well. I was able to work my way down to a 1:43.1 on hoosiers which tickled me pink. Unfortunately I had gopro issues that session so I only got a few 1:47's on video.
The purple crack is going to be a hard habit to break. Luckily the track hours per dollar are actually pretty reasonable if you can find a steady supply of take offs. I had an epiphany in the last session and the track started feeling like an auto-x to me, I owe this to the forgiving nature of the hoosiers honestly. I was able to get on the edge of traction and keep it there in most every corner and of course my times dropped. Still kicking myself for not getting the video of that session.
Just got back from Summit Point, huge amount of progress since last year, dropped from a 1:30.1 to a 1:25.3 this year. The new pavement is worth 1-2 seconds and the hoosiers are worth 1-2 seconds as well since they were at the end of their life. The rest I'd like to think was just my skills improving. I usually track with a group of friends most of which are instructors with Chin, I got the Hillbilly Stig, Luke McGrew to take the car out for a session to see what it was capable of, the dude is fast in anything you put him in. You'll see him at grid life in an ACR. He was able to get down to a 1:23.8 in just a few laps.
My fastest followed up by a few more pretty quick laps.
We noticed that it was possible to overheat the hoosiers with my power level. After about 15 to 20 minutes they started getting greasy and sliding around too much. I had hoped to stick with the cheap hoosier take offs so I'll either have to live with this (not a big deal) or contemplate moving to a bigger tire (expensive new) or stepping into a harder longer lasting tire that is much slower.
I finally figured out the funky miss I was having at Mid-ohio, seems you load up the engine in ways that are impossible to duplicate on the street so a data log with the SD card and VE table true up got my 10.2 AFR's back in line so the motor pulled cleanly at part throttle.
I also took the time to do a little testing on the cooling system, it's been kicking *** and taking names since day one but I really didn't know how much excess cooling capacity I had (more on why later) I had originally thought of installing a divider to bias the airflow but then it dawned on me that simply taping up the radiator would force more air through the intercooler. I started off with 1/3rd of the radiator taped off and it slowed down the cycling of the thermostat but it was still riding it. I added a few more pieces to get to 50% blockage and once again the temperature swings leveled off more but still staying right on the thermostat set point. I did notice the temps started creeping up to 205 while sitting on grid after a black flag which still isn't bad but the fan wasn't keeping up like it normally does. I only taped the part of the radiator that did not have a fan on the back side, so I surmise that there was a certain amount of natural convection flow of hot air rising out of the hood even when stopped. I did notice the intake temps recovered much quicker but still cycled between 110 and 130 degrees on track at 13psi.
What' next? I of course have plenty of learning left to do and lots of time to be found with more experience. I'm on borrowed time with the current long block at ~25hrs on track, I'm making an easy 250whp and we all know a thrown rod is likely eventually. I have the parts to do a forged bottom end but I would still need to spend some coin to get it installed. Once that's in place another 50hp would let me play with the C6 zo6's on the straits but also make the 6 speed a wear item which it already is to a certain point. So where I'm at is I can't really leave it as is and keep tracking for much longer without risking the motor.....if I'm going to touch it more power is the only sensible next step.
So enter the LS2 swap.......yeah I skipped a few steps. My thought process is that I'm looking at 1-2k to get the motor finished and pick up a 2871 and then I'm on the ragged edge with the rest of the drivetrain. I added up what I could get parting out my current setup and started looking at what my costs would be to do an LS swap. Keeping in mind I can do my own fab work, I think I can get it done with CD009 or Getrag 260 trans and getrag rear diff for just a grand or two more than I would have in stepping up to 300whp with the BP. Then I have a bone stock motor making 350-370whp with a trans and diff that can take tripple the power I'll have. I'm playing with the weights but it looks like I can keep the gain in check (Goal of less than 100lbs added). This will also give me a ridiculous ~6.5 to 1 power to weight ratio. The cooling system is ready to go, the brakes will need a touch more cooling and I'll have to step up my tire game slightly. The allure of going full retard seems too strong to ignore, the sensible thing to do is keep it at the current power level and get more seat time.......but what fun is that? Stay tuned.....
Scored this rebuildable LS2 for $500 which spurred this endeavor.
Got a chance to hit the drag strip one more time before I yanked the turbo driveline......FINALLY pulled off what I knew the car was capable all along. I was able to run a 12.6@104 earlier in the day but tried to ride out 4th gear and was on the limiter too long. This run here was a 12.8@108, the track was cooling down and I wasn't able to go full throttle in first so that explains the ET difference even though the MPH was where it should be. Think there is a 12.5 in there pretty easily with some sticky tires or just a good launch.
The white E30 is the other lane is my buddies, it's got a blown LS and run mid 11's at 121.....it's his fault I'm going LS.
01-17-2018, 09:30 PM
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I usually track with a group of friends most of which are instructors with Chin, I got the Hillbilly Stig, Luke McGrew to take the car out for a session to see what it was capable of, the dude is fast in anything you put him in. You'll see him at grid life in an ACR. He was able to get down to a 1:23.8 in just a few laps.
