Progress Thread Grover: Window motor replacement & OEM rebuild

[FastDriver]

The trusty BFG 295/35/18 Drag Radials have had it! It's time for new ones.

Problem is, they don't make them in that size anymore. I'd definitely like to stay with an R-compound tire. The fact that the BFGs rubbed means that I absolutely cannot go any wider. I don't like the rubbing anyways; so, I'd be open to downsizing.

I'd love to find a 275/40/18 because that would be only 0.5" taller and might bring the tire in enough on each side. I'd also go for another 295/35/18. Mickey Thompson makes a 285/40/18 Drag Radial that might be the only way to go. I'm just worried that since it's 1" taller and barely narrower, it might not work.

Edit: I've been digging. The best I can come up with is the Nitto NT01 in 275/40/18, which is a track HPDE type of racing tire. I think, however, that I really need to keep a no BS Drag Radial on the car, or I'm never going to plant the power. So, unless anyone has a better recommendation, it looks like I've gotta try the ET Street SS that may not fit well. Since the car is on coil-overs, I think adjusting height is not too tough.

 

[FastDriver]

So it turns out that Nitto makes an NT05R in both 295/35/18 and 275/40/18. I just don't think I can bring myself to put another Nitto on my cars. I had a couple sets of triple-nickels for lower powered cars and found them severely lacking in comparison to the other Drag Radials I've experienced. Perhaps the NT05R is much better, but I'm still reading that the MTs are stickier. I haven't pulled the trigger yet, but I'm starting to lean toward giving the MTs try and falling back on the Nittos if they don't fit well.

 

[TOOLOW91]

RXT and RST have, I believe, the same clamp load. The RST is organic, whereas the RXT is ceramic. It's capable of holding a lot more power, but should have more chatter and shock the drivetrain a bit more. On the bright side, ceramic handles heat a lot better, which is more appropriate for burnouts and slipping the clutch on the launch. The RST is rated at 800 hp, the RXT is rated to 1000.

With all of that said that’s why I think McLeod doesn’t reccomend drag racing with the RST . I didn’t notice hardly any chatter out of my RXT. Maybe once or twice in a heavy stop and go traffic situation but that was it

 

[TOOLOW91]

So it turns out that Nitto makes an NT05R in both 295/35/18 and 275/40/18. I just don't think I can bring myself to put another Nitto on my cars. I had a couple sets of triple-nickels for lower powered cars and found them severely lacking in comparison to the other Drag Radials I've experienced. Perhaps the NT05R is much better, but I'm still reading that the MTs are stickier. I haven't pulled the trigger yet, but I'm starting to lean toward giving the MTs try and falling back on the Nittos if they don't fit well.

I agree on the 555s . Only plus is they last way longer then any other drag radial . My buddy just picked up the nt05 for his TVS blown yote . So I’m curious to see how they work out

 

[Essn95]

NT05R would be my vote, had them on a C6 Z putting down nearly 700 wheel and it handled it quite well

 

[FastDriver]

I was wrong about the NT05R sizes. They are not available. I was looking at the NT05. Wrong tire!

I started getting crazy ideas about driving around on NT01 competition road racing tires, but that would mean I'd also have to figure out a complete extra set of wheels/tires for launching the car. My set of Cobra Rs would have gotten some drag tires. However, I that would require a purchase of 8 tires. I thought better of it, and I'm going to try and get the ET Street SS 285/40/18 to fit. For now, that means I'm buying only 2 tires. I may revisit this decision in the future, but for now, this just makes much more sense. The front tires are perfectly good and it would be a waste to swap them for the road race stuff now. I might even use the Cobra Rs for road racing tires one day, and that probably makes more sense based on their fitment, anyways. It's easier to put a 9" wide wheel/tire in the rear fender without rubbing issues than the 10.5" wheel on the car now.

 

[FastDriver]

ET Street SS 285/40/18 tires are now on the rear. There is a definite improvement in traction, which is no surprise to anyone, compared to the bald BFG Drag Radials. Where as I could not keep traction in 2nd on 10 psi, now it dead hooks. Where as I could not get traction in 3rd at 13psi, Now, it dead hooks in that gear. It still doesn't hook in 1st, but at least on low boost, even when it spins, it still pulls like hell, as opposed to the BFGs which just went up in smoke and vastly compromised acceleration.

I did not notice an issue with sway to this point, except when I sawed the steering wheel a bit to induce it. Then I could definitely tell the sidewalls were softer. I'm really happy with this decision. I think it was the right call, since they seem to fit fine.

 

[FastDriver]

 

[TOOLOW91]

Size looks perfect on there too

 

[HotFox]

Looking Good! When you going back to the track?

 

[FastDriver]

We'll see. The track is a 2.5 hour drive towing. I'd like to tune the timing a bit more before my next TNT.

 

[a91what]

whats the total timing now at max boost? mat temps? octane? cylinder head? comp ratio?

 

[FastDriver]

I'm tuning for 91 octane. It's an AFR 205 head. Compression at ~9.6. Current timing at max boost is 14.8*. However, I'm not really trying to see that amount of boost. So, 15.8* t at 13-14 psi, though you can see that through a run, the boost spikes, goes over target by about 2psi and gradually drops to target through the run. Here's my setting that targets 11 psi. It makes 13.9 at the beggining of the spike and 11.2 at the end. This kinda sucks, because if anything, the opposite is preferred to reduce traction issues early. I'm hoping that powershifting will allow boost to stabilize at target, as opposed to spiking in each gear. This observation doesn't seem to be just related to the boost controller. Even on the spring, the effect is similar.

Anyways, Here's a snippet of my recent data log. I've made some minor adjustments to AFR. I was setting the boost controller at the time, but I was using it to help dial in the AFR. It's obviously running pretty rich at this point. I think I pulled out around 5% more fuel at those points after this run, and that's where she currently sits: I cannot find MAT temps, unless 70-80* sounds right at WOT, which I find hard to believe. I'm guessing that's measuring ambient air.

After I get the AFR where I want it to be, I'd like to try my hand at reading plugs to adjust spark. Some of the best tuners in my area say that's the best way to do it.

Another thing to note in this graph, I'm not impressed with the transient tuning of this box and/or my ability to tune it. You can see how rapidly MAP spikes, yet the dmap doesn't even leave its cell after that AFR low valley that intersects the TPS going WOT. So, I've resorted to using the 3500 RPM column in the VE table to compensate and have values there considerably higher than surrounding values to deal with the boost threshold there.So, part of that rich AFR thereafter is the computer recovering from VE values that are intentionally too high, but there's still room for adjustment afterwards.

 

[a91what]

IMO i would not worry about the timing at this point, your fuel is way to rich. I try to never go below 11.5 AFR unless i am cooling a cylinder for whatever reason. you will see about 15% increase in power going from a 10.5 to 12AFR I would shoot for a 11.8-12 AFR

These table are fairly simple to tune with basic math, assuming the usage of a VE table you can take your actual AFR and divide your target AFR into it to produce a multiplier.....

actual [have] AFR/ target [want] AFR = VE multiplier

target= 12afr
actual= 10.6afr

10.6/12 = .8833333

so based on this simple equation you are about 21.7% rich at this VE point

Of course i do not have the BS3 fuel equation to look at so i assume it works like the MS/Holley/Haltech stuff
Pm or post a link to the BS3 manual and i will see what i can about helping to figure out the ^map enrichments you are having an issue with... is there no option to do the enrichment for ^tps or tps-dot??

 

[FastDriver]

Oh yes, you very much can tune with TPS values, but as you can see from the graph above, it's going plenty rich at the instant of WOT, now. In fact, I'm pulling out the enrichment there, because it's going too rich. It's shortly thereafter where the AFR crosses desired, goes lean, and nothing in the transient seems to affect that. So, I compensate in the VE table, but the trouble with that is that it while it keeps the car from spiking lean, if forces it to go too rich once boost stabilizes, at least until it completely exits those cells.

I'm with you on the math, and that's exactly what I've been doing between runs. I'll approximate the percentage, and then put a conservative adjustment in. I'd rather creep up on the rich side. Now, Steve, don't take this the wrong way. I well know that your tuning experience is vast compared to mine, but everything I've been reading, and videos I've been watching, lately says that once you're in the ballpark with AFR, you don't get those kind of gains. The only massive gains you'll see from AFR, according to those reads is 1) if you go too lean, you'll lose a lot of power, and 2) if you're so rich that it's interfering with the burn and/or spark. Most of these articles and videos were n/a cars, though.

The takeaway to me was that conservative fueling, say 11.5:1, will give me a nice hedge against detonation without costing much power. Now, I would very much like to see a back-to-back comparison, dyno or track, on a turbo application with no timing changes going from a rich AFR of say 11:1 to say 12:1, or whatever optimum is. 15% is A BUNCH of power to give up when you're making 600+. This is the kinda thing I will test for myself on a dyno if necessary.

I'm also with you on getting AFR where I want it first before adjusting timing. I haven't changed timing at all to date. In fact, I'm planning to swap plugs after I'm happy with AFR values, before I begin messing with timing.

If you'd still like to read up on the BS3, here's the link you asked for: http://bigstuff3.com/pdf/GEN3 User Manual - Feb 2011 - Rev 2.2.pdf

As this is becoming increasingly technical, I think it's time to exchange numbers so we can go direct. Check your pm.

 

[a91what]

My power gains estimate is based on some good reading from Kenne Bell, I am simply quoting his words and those gains are based on a mod motor with a PD blower. I have noticed gains at the track using the advice i found in his tuning FAQ. I do not agree with his estimation of power gains with timing however as i have felt no difference creeping up from 22* at 10psi to 25*.... plugs looked clean but i must have already been close to MBT as I noticed no Appreciable difference.

 

[FastDriver]

So, check this out. I think I modified these cells in the box once since this log. So, the numbers in the cells are not exactly what the computer used in this run, but it serves the purpose. It's the same run as before. As you can see, the boost spike goes through the 3500 column and when it gets levels off, the top cell is 98. The one to its right is 91. Even with the 98 at the top, you can see that where the spike apexes, it still goes slightly lean. Now, we're only talking about 12.2:1, and that exact lean spike occurs at the 100 cell in the table (it was 98 at the time of this log). I have to be careful where it initially goes too rich, because I must also consider that at higher boost levels, the spike will go through this cell on the way up, and I don't want it to lean out there. So, the 98 cell at (4000,13.6) is causing it to drop AFR deep into the low 10s. Way too rich. It does transition up close to the desired AFR when it gets into the 91 cells.

If I transition through these cells at flat boost, the Actual AFR is far richer than if I'm transitioning through with a vertical boost line. Transient should be what I'm using to compensate, but the MAP transient tables just aren't getting the job done. So, the only thing I know to do is compensate in the main table. It puts me in the position of either running too rich when the boost levels off, or running too lean when boost is still going up. I choose the safer option.

 

[a91what]

I understand, the dmap should add enrichment based on the map delta or 'rate of change' ... with an increasing map signal the dmap enrichment should be active in the log but looking at that point it is at 0% enrichment. The dmap enrichment should also have a taper value.. i believe thats the [dMAP tpr] it shows 0x72... from my limited knowledge of BS3 i assume that it is taking the 0% enrichment and it will taper by 72mS....

bottom line somthing is wrong with the map based accel enrichments. I prefer the tps based enrichments myself but will need to look through the manual to see if they are possible

 

[FastDriver]

they are possible. In fact, I am using both in this log. However, the only place that they are applied is in the immediate 10th or two of a second after going wot. I'll try to get another screenshot when I get back to the computer. it's like the D map is not sensitive enough to pick up the Boost Spike.

 

[a91what]

join me in the digital tuning chat room so we dont clutter this up and i will be calling shortly