QwkTrip

iTrader: (22)

No, I didn't. Spent all summer driving and having fun on a 80% tune because that's all the car could support. Finally got things sorted and kicked up the tune in October, and then winter arrived early and that was the end of that. Only got to drive it a few days after the tune.

I will probably go to the drag strip one time this coming year just for kicks and grins. I'm not a drag racer and don't have a drag car. Guarantee I'll run 11.xx, with the first half of track looking like a 12 second car, and the second half of the track looking like a 10 second car.

QwkTrip

iTrader: (22)

Got a flawless, used set of fat man Recaros. Fits like a glove.

Not the best color combo for my car, and not excited about the embroidered Firebird, but hey, I've been around long enough to know when to take a good deal. I could never afford these new. Even has a cute little squeeze ball for a lumbar air bladder. Now I've got to figure out how to keep the seat belt from rubbing my neck.

Story goes these were made for a guy that worked at Recaro. Car had only 26K miles and the new owner sold the seats to me and dropped $11K to custom upholster the stock interior and plastics.

ShiftyCapone

iTrader: (7)

Good find. Those look nice, even if you have to reupholster them to get rid of the bird. Or just put a walmart camo seat cover over them . Aftermarket seats are so expensive and finding a good used set is hard. I have recently been looking at a company called Braum. I had never heard of them until recently but they make beautiful seats. $900 to $1200 each though.

QwkTrip

iTrader: (22)

I just noticed the front bottom cushion slides out a long ways for more leg support. I wonder what else these things do that I didn't know about!

skinny z

Nice score.
We've got the Procar in the Chevelle. Recovered in leather to match the rest of the interior as their version of red is certainly biased more towards salmon pink. All in all a decent seat. But they ain't Recaros.
https://procarbyscat.com/product-cat...ype/recliners/

427seven

well, if you believe all the bench racers, yer in fer a happy ending....

TTOP350

iTrader: (8)

Those look killer !! And comfy!

ShiftyCapone

iTrader: (7)

Wait till you are at a traffic light vigorously using the lumbar pump and making eye contact with the car next to you. "Honestly....its not mine...its not my bag baby". The swedish ones are the best.

LAFireboyd

iTrader: (3)

Funny. My passenger belt is RED! Guess mine isn't the only "error." A dirty little secret, it looks like, but it's apparently not uncommon. Accidental, intentional, lack of correct color, or whatever, they probably figured it wouldn't matter anyway since the belts were sleeved. Doubt they'd anticipated such a short lifespan for those plastic sleeves.

You'd mentioned having the Ultra Plush carpet from Jim in another thread, so I was skimming this thread to find pictures of your interior and carpet. But when I found this post, I had to laugh and comment! I did find some of your carpet, by the way, and it looks nice. Do you remember what the name of the color is/was?

In the Ultra Plush carpet, currently only one grey, Medium Grey, is listed. Not sure what was offered way back when you and I shopped with Jim, but the current Ultra Plush Medium Grey sample on the computer screen doesn't appear to match the sample of Cut Pile's Dove Grey on the computer screen. My floor mats, from Jim, are Dove Grey, and they're a good color-match for GM's Medium Dark Grey interior, so I'll have to wait for a physical sample of the Ultra Plush Medium Grey to arrive to see how it looks in the car.

And thanks for the tip on those seat belt sleeves. I'm about to do this. They just arrived yesterday from Hawk's. Now I'll know what to look for.

QwkTrip

iTrader: (22)

I don't know. I just let Jim figure it out and I got what I got. I told him I have a '89 Firebird base model with the light grey interior.

QwkTrip

iTrader: (22)

Oh yippee..... tune went to **** just sitting over the winter. Something is REALLY wrong with it and I can't figure out what. Acting like it did last year when the ECM went on the fritz.

Now that's the old girl I remember. Don't need none of this reliable crap or you just get bored with nothing to do.

IROCZman15

iTrader: (25)

haha! when things are going great, something is bound to come along and screw it up. !

QwkTrip

iTrader: (22)

Update: I've concluded this is all junk and turned it off in my tune. Leaving the info here but do not recommend doing it.

So this is what I was working on when things went haywire.

I learned that the Holley HP EFI does not account for changes of barometric pressure. SAY WHAAAA????? Ya, you heard me right. The ECM literally has a Barometric pressure sensor inside the ECM but those yahoos didn't do anything with it. The system relies solely on the closed-loop mode to change AFR with altitude and weather changes. Well that's all fine and dandy until you're not in closed-loop any more, which is a lot, so I set out to fix it.

First I examined how air pressure changes with altitude, using the troposphere math model at https://en.wikipedia.org/wiki/Atmospheric_pressure . Luck would have it that the relationship is pretty much linear (straight line) in the lower troposphere where we do all our driving. That means nothing funky is happening with air density, so I can apply the Ideal Gas Law and be close enough.

Air Density = (P * M) / (R * T)

Where,
P = Pressure (Pa)
T = Temp (Kelvin)
M = 0.02897 kg/mole
R = 8.3145 J/mole-K

Drop that crap into a spreadsheet, run the calc at every pressure of interest and constant temperature, and you'll get percent changes relative to sea level like the table below.

Holley HP EFI: custom 1D table, Fuel Flow Multiplier (%) as a function of Baro pressure (kPa)




Here is a much less aggressive baro pressure compensation scale based on the Density Altitude model and some big assumptions. Density Altitude equations are located at, https://en.wikipedia.org/wiki/Densit...%20sea%20level

I've never driven at altitude yet to see how any of this works. And honestly I'm starting to think this is all a bunch of hooey balooey and that I'm going about it entirely wrong. Maybe what I'm really after is just a slight engine Volumetric Efficiency compensation with Baro changes. I haven't found any information yet how to do that.

dixiebandit69

Are you serious? You got that response from Holley's tech support?

QwkTrip

iTrader: (22)

Yeppers. I was just as dumbfounded as you.

TTOP350

iTrader: (8)

Wow...

QwkTrip

iTrader: (22)

Oops. I was the problem. LOL! Word to the wise, don't literally zero out (0%) a fuel compensation table. Use 100% if you want to effectively disable it.

230 firebird

i know this is an old thread but I need some help.I hooked my box up like this exept i used output three to get my signal right.Thing is my speedometer works but odometer doesnt add miles.Any thoughts?

QwkTrip

iTrader: (22)

The factory speedometer is looking for the 4000 ppm OC signal (Out 4) which is a square wave that is above 0V. You're using an 8000 ppm AC signal (Out 3) which is a sinusoidal wave that goes below 0V. Fix that first before fiddling with anything else. I think I have all the dip switches in the OFF position, but I don't remember for sure. If that doesn't work then you'll be repairing or replacing the speedometer.

230 firebird

Ok, thanks.I will try that.I do know the problem must be the way I have it set up because I have 2 Firebird clusters,1from v6 car and 1 from v8 car and neither will work . I got my info from tech at D.D and they said use “3”. I swapped in a TKO 600 and am trying to go from a high signal to low.I don’t really understand about these “signals”

QwkTrip

iTrader: (22)

The type of speed sensor in the transmission will change the settings you use for signal conversion, but it won't change the wiring to speedometer.

Honestly, I thought the user manual kind of sucked. I would have used the wrong settings had it not been for an electrical engineering friend. My settings are different than anybody I've ever seen here.

dixiebandit69

See, stuff like this is why I think it's better to use the factory PCM. If GM thought they were going to have a problem on the MILLIONS of LS powered vehicles they made, they'd take care of it.

Then again, I've seen GM ignore some pretty obvious problems over the years...

QwkTrip

iTrader: (22)

M&H drag radials on order.

Learned a little more about these tires. It's definitely a different tire from the Mickey Thompson and it will be a different experience - guarantee that. These M&H tires have a poly fiberglass core (not steel). The sidewall is softer and the rubber is harder than the MT so probably won't ball up as bad. Time will tell how well they hold traction with some miles but I'm game to test it.

skinny z

My decision will, in part, be based on your testing. At the moment, it's between the M/T SS radial and the M&H.

IROCZman15

iTrader: (25)

keep up posted. I need to learn from people in the know!
-Currently, I think I am going to try the Mickey Thompson ET streets on my 16"x8 iroc wheels for now. https://www.summitracing.com/parts/mtt-3460 SkinnyZ and I were discussing this in my build thread a few days ago. I have an auto trans and these tires/wheels will only be used at the track to run 1/4 mile passes.
- I want to keep a more corner-carving/autocross street tire on my rear 18"x10" fancy wheels so I will probably go with the falken azenies https://tiresize.com/tires/Falken/Az...-295-40R18.htm .. but when my nitto 555 rears wear out. several months remaining still.

but let us know how you like them and that will help me(us all) decide for next go-around

QwkTrip

iTrader: (22)

M&H tires ready to roll with nowhere to go. Yesterday I was swapping tires in sunshine and today there is snow everywhere. And the whole Coronavirus thing is going to give me nowhere to go too.

Fortunately I have a pile of parts squirreled away that I can install if things get boring, so there might be some project work this spring after all!

IROCZman15

iTrader: (25)

awesome!

My M.T. ET streets arrived yesterday also! no snow here in NJ so I can hopefully get them mounted and road tested next, but I am unsure if my local dragstrip will be having any upcoming Test and Tune events due to the global virus pandemic (thats an interesting phrase I never thought I would have to say!!).

those look good, what size did you go with

QwkTrip

iTrader: (22)

275/40-17
I only have the one set of wheels.

QwkTrip

iTrader: (22)

First drive and not impressed with these M&H tires in the slightest. Just made me want my Mickey's back. I'll give it another chance but this might be a very short lived relationship.

IROCZman15

iTrader: (25)

I can't claim to know much on this topic as I am brand new to the drag radial world, but I had read that I needed to "scuff up" my new drag radials a bit. I put about 80 miles on them last week and a few short burnouts and they have been working great. I do have less power than you, but anything specific for a "break-in" process for those M&H ?

QwkTrip

iTrader: (22)

Nope, just slap 'em on and go driving. Heat cycling does not extend life like it does with a high performance road tire.

You definitely DON'T want to scuff them up. Big no-no. Scuffing will tear up the tread and cause balling of the rubber and loss of grip. The street dries out the tires, so every now and then you'll have to do a short burnout on a smooth surface to rejuvenate the tread with oils. Avoid burnouts on blacktop roads because it can tear up the tires big time.

Basically you've got a track tire on the street and the street is going to ruin it and it's never going to work like it would at the track. Nobody actually gets to prep a tire for a race on their way to Wal-Mart.

IROCZman15

iTrader: (25)

woah, interesting. I had read the opposite for a brand new set of tires, but I know that you are a knowledgeable trustworthy source, so I am definitely going to take your advice on this topic. good to know. thanks.
-I was running about 28 psi in them (255/50/16 on an oem 16x8" iroc-z wheel) and was told to run about 18-20 psi at the track (whenever the tracks are allowed to reopen). does this psi sound about right to you?

QwkTrip

iTrader: (22)

I have almost no track experience. Remember, I might have set the world record for slowest 60' time on a drag radial.

I think Mickey Thompson recommends the highest pressure you can run before traction suffers. When you do your burnout hit it like you mean it, but just go for a few seconds. Enough to haze the tires (a little smoke). I think MT wants tire to be about +15°F hotter than the road surface (I'm going on memory here). The big smokey burnouts are for the guys on bias ply slicks. Your drag radials will get greasy if you heat them up too much. And don't test traction with a dry hop, just line up and go.

QwkTrip

iTrader: (22)

The reason I destroy tires so fast is because I'm constantly scuffing the tires under heavy throttle on the street. Absolutely wrecks the tires. It's like rubbing the tires with a cheese grater.

ShiftyCapone

iTrader: (7)

700 HP problems

QwkTrip

iTrader: (22)

I’ve been contemplating trying to adapt a DCT transmission to the car. Not easy yet, but it will get easy once the aftermarket cracks encryption of the transmission controllers.

But before I get too serious about such a drastic change, I figured I should get a little better understanding of how a car gets down the road. I've always heard things like horsepower wins races, shift at rpm as high as you can, 7 speeds are better than 4 speeds, steeper gears make a car faster, larger tires slow it down, blah blah blah.… But is it really true? I wanted to be able to visualize these things for myself so I made a spreadsheet with graphs to compare scenarios. It's basic, not real fancy, but I think the results are pretty interesting nonetheless.

For this comparison I used an engine dyno curve that I found online with data from 2000 - 6500 rpm. Engine makes 325 lb-ft torque peaks at 4500 rpm, and 322 Hp at 5600 rpm and carries to 6000 rpm. I used the gear ratios for a T56 transmission. Baseline tire diameter is 26 inch.

Engine torque is only part of the story though. The torque has to be cascaded through the drive ratios of the gear train in order to derive the torque applied to the ground, or more specifically the Driving Force of the tire to ground that accelerates the car. So I figured if I track the Driving Force vs. vehicle MPH then I'll get a pretty good idea what combos work better than others. There might be a better way to look at things, but that's how I did it this round. Each graph below shows,

* Horsepower vs. MPH. This shows where the engine is in its Hp curve.
* Final Ratio vs. MPH. This tells what is the total drive ratio through trans & axle gears. It changes whenever the transmission shifts gears.
* Area F-curve. This is what I'm really interested in. It's the cumulative area under the curve of the Driving Force as it sweeps across vehicle MPH. My assumption is the car with more area under the curve is the faster car.

Effect of axle gears

I’m glad I looked at this because the results were different than I expected. I did a comparison of horrible 2.73 gears vs. 3.73 gears with everything else the same. The chart below tracks area under the Driving Force curve from a 25 mph roll. It's really clear by separation of the curves that the 3.73 geared car gets up in the power-band quicker and absolutely clobbers the 2.73 geared car. But the benefit is gained early in the run in 1st gear and 2nd gear. After that the two cars run nearly identical, with a slight advantage to the 3.73 geared car. And that advantage could easily dissolve depending what gear ratios are in the transmission.

Looking at the graph of Final Ratio, the 3.73 geared car has a huge mechanical advantage until it drops down into 3rd gear. At that same mph the 2.73 geared car is in the power-band and still running in 2nd gear, resulting in a similar overall mechanical advantage. Of course, the 3.73 geared car is long gone by this point.... but if the race started at, let's say, 50 mph, then it would be pretty much neck and neck. And the even more interesting part is I ran a bunch more axle gear comparisons and found that almost any gear ratio will perform the same at highway speed until dropping into overdrive. It really cements the concept that the launch is everything in a drag race!

So I think what I learned here is that,

(1) If you have steep gears then your advantage is at slow speeds; and
(2) Highway rolls are won by engine Hp.







Effect of shift points beyond peak Hp

The next thing I did was look at the effects of shift points. After all, I can use this knowledge right now without even changing my set up.

Looks like the simple answer is rev is to the sky. This one didn't surprise me at all though, because every gear shift is a huge loss of mechanical advantage and torque at the rear wheels - far more loss than the falling torque curve of the engine near redline. Rev that sucker and stay in the better gear if possible.




Slide the torque curve up to higher RPM’s

So this is a quick test of the old saying, “Horsepower wins races.” What I did was slide the entire torque curve +500 rpm to raise the power band of the engine. I already know that raising shift points matters, and this is like giving even more power on tap at those higher shift points. It’s a no-brainer. Horsepower does matter.




Bring it all together

Now that I’ve seen trends, it was time to stack things together for the cumulative effect. This time I gave the baseline car a fighting chance with 3.50 gears and a shift point a little beyond peak Hp at 6000 Hp, like a lot of people would do. The other car has power-band +500 higher, 4.10 gears to compensate for loss of low end torque, and shifting at 6500 rpm redline. The net effect is a car that walks the baseline car hard in any scenario.




Is a transmission with more gears better?

Honestly, I was expecting the answer is always “yes”, but it turns out the answer is “depends”.

First I looked at the 7-speed DCT transmission from the new 2020 Mustang GT500. Even though it has 7 speeds, it still just has 4 speeds usable for drag racing. The Mustang DCT trans has more aggressive gears than the T56, but I was able to compensate by adding a lot more rear axle gear to make the T56 pretty much overlay the Mustang DCT transmission. Obviously the DCT has other advantages like lightning fast shifts, but I’m just comparing power to the ground for now, and it looks like a wash in that department.

Then I noticed the BMW M3 DCT transmission uses a totally different philosophy in regards to gear ratios. All I can say is the Germans got their crap together. They have a 7-speed trans with no overdrive, and drop the axle ratio down to 3.15, giving 7 usable gears for racing. I put together a scenario where both cars have the same engine and shift points for direct comparison of transmissions. The T56 car is mated to 3.73 gears, while the BMW DCT trans is mated to 3.15 gears (like a real M3). Basically the BMW M3 DCT has an advantage everywhere. 1st gear is very aggressively geared to slingshot off the line (if traction is possible). And the DCT advantage continues to slowly grow at high speed too with higher final drive ratios and less rpm drop between shifts. I'm thinking maybe the best way to take advantage of a trans like this is with a high revving engine to get the best of both worlds. You don’t need low-end torque because the trans gear ratios is doing it for you.

One thing that is apparent from all this is that quick movement thru 1st gear is key to a fast car. That's kind of the "duh" part, but maybe what wasn't so obvious is that focusing on things after 1st gear yields small returns. The new cars have very aggressive gear ratios at slow speeds - way more aggressive than what I have and what is typical for old American V8 cars. Maybe there is something to learn from that.

ShiftyCapone

iTrader: (7)

Qwk,

Interesting work here, and I can see you have found the limitations of keeping yourself occupied during the quarantine.

I have a similar program that I made back in my undergrad days that similarly models vehicle performance. It gets pretty nerdy though as it was an project for one of my dynamics electives. I'll see if I can dig it up, but I modeled it after a 1995 stock LT1 M6 car and the results were dead on, so I could plug in any other car with reasonable accuracy. The professor was a consultant to some top fuel drag racing teams and was really focused on tractive vs traction forces on tires at launch. His key take away for drag racing was dialing in just the right amount of tire spin at launch (if using bias ply or drag tire), but he had a model for radials too. He was a cool dude.

skinny z

That was the great equalizer way back in my street racing days. Case in point (circa 1980): Two 68/69 Chevelles. One with 400 CID and a stock stalled TH400 and 3.08 gears. The other with a 427, 4 speed stick and 4.11 gears. My little 400 was totally crushed by the other Chevelle from a standing start. Several car lengths right off the line.
After all of the commotion (and embarrassment) I returned to scene of the crime to find the other Chevelle hanging out after the crowd had left. I prompted him into a rolling start race from about 30 mph which put me in the meat of my torque curve in 1st gear. End result, fender to fender the entire race.
Interesting analysis you have going on there Qwik. I can especially relate to drop in RPMs on the shift particularly with the 700R4 and the wide spread between ratios.
One thing not analyzed is the effect of a properly matched torque converter. We gained a couple of tenths with a switch from a 10" TCI to a spec'd Yank (9.5"). Even with the large ratio spread that Yank converter never let the revs slip below 5000 despite the gear ratio being closer to 3800+/-. That would be a similar effect to a close ratio modern trans I would think.

dixiebandit69

Too bad they don't have their crap together when it comes to reliability, longevity, ease of maintenance/ repair, or build quality.

Seriously, whenever a German car comes into the shop, I feel like someone just handed me a brief case with a red LED display counting down to zero.

QwkTrip

iTrader: (22)

Gettin' pretty close. I just let the differential drain for 5 days too. Why? Because I could.

Just a note for myself so I don't have to figure this out again for my Strange 12 bolt:
2 quarts Lucas 85W-140 (non-synthetic)
4 ounces of AC Delco limited slip additive
Spicer cover gasket p/n RD51996 (composite with steel core)

ShiftyCapone

iTrader: (7)

Ha, my suburban is in desperate need of that.

QwkTrip

iTrader: (22)

Illinois just extended stay at home order another month AND the rules have gotten tighter. This is becoming ridiculous. I was one of the first people at work to leave and say I'm working from home, but even I think it's now gone too far. They're so single mission oriented that they can't see it is destroying our country and eroding an entire generation of wealth.

92BLKL98

I don't know if the mods will kick me off for this but you ought to read this. Kind of makes you question what's going on, at least it does me. AHSOOO https://www.freedomandguns.com/actor...d-hypocrisies/

BADMAN

iTrader: (13)

Harris County(Houston) just did the same. County Judge doesn’t know what she’s doing. Sowing the seeds of dissent.

QwkTrip

iTrader: (22)

COVID lockdown: Cleaning rod end bearings for entertainment. And the sad part is people that walk by have this longing look in their eyes like they wish they could do something this fun.

These are teflon lined joints and I didn't know what is the right lubricant to use. I sprayed the rotator ball with Amsoil off-road motorcycle chain lubricant, and greased the bushings with lithium grease. Anybody got better ideas?

QwkTrip

iTrader: (22)

I might have found one of the reasons why my car spins so much and doesn't launch worth beans. It appears as though the torque arm can get bound up at the front. So basically sometimes it might be pushing into/down on the chassis when it should be pulling up. Can't see in this photo, but there is a gusset on the torque arm that is sitting hard against the crossmember mount. Longer swing plates will fix it. Not to mention it won't break off the zerk fitting any more either. That was a terrible place for a zerk fitting anyway.... But if you think that's bad, you should see where the top one is!

So now to hunt down some 1/4" steel and a new zerk fitting!

obeymybird

iTrader: (4)

Also look at the angle of the arm this will make for traction issues not talking about pinion angle.

QwkTrip

iTrader: (22)

Thanks, that's a good reminder that I really should map things out for once.

Although, I think that's a 4-link diagram, right? I think to find IC for a torque arm suspension you drop a plumb bob from the front torque arm mount and see where it intersects with the line from the rear control arm? Is that right?

obeymybird

iTrader: (4)

The diagram was posted by BMR for a guy trying to dial in his launch on a 4th gen. I will find the link maybe it will be useful.

Some good and bad info lol.
https://ls1tech.com/forums/drag-raci...djustment.html

skinny z

I've always understood that the torque arm didn't work as illustrated and that diagram was directed to the 4-link style. The thread at LS1 tech follows that thinking (the BMR tech back pedals some when called out on this). That said there is some good info on dialing in the suspension on the 3rd/4th gen. Particularly with reference to the LCA angle and shock settings.