Ralph,plug a 2.75 to 1 trans. 1st gear.I can get my 60' times down with this setup.
Remember,I ran a 11.41 in the summer time with the ZF.The ZF has a 2.68 trans. 1st gear.My "starting line ratio" was higher than my current combo.IMO,the EFI car want a ton of SL ratio.Traction then becomes an issue.
Woodrow Josey run a NHRA DS/A Firebird that uses a 2.75 1st gear/4.88 rear ,but with 30" tires.His car has gone 10.58/124 at a 3255 car weight.
Let me know what the SIM says.Look at the 60' and the 1/8 mile times.
Phil

 

Phil. Two essential readings for a start. http://www.thirdgen.org/newdesign/tech/promintro.shtml http://www.thirdgen.org/messgboard/F...ML/000637.html

This is the best place to start. Its how I learned.

Jason

 

Interesting comparisons....

I entered what I remember of Phil's set-up from previous conversations in the simulator and played with some numbers.

I haven't a clue on how accurate this is, but interesting never the less:

Baseline: 3350 raceweight, 3200 stall, 3.73's, based upon a MR type torque curve and Phils dyno peaks, Turbo 350 tranny gears:

1.64
11.60
118.01

I then gave it more gear with 4.11's

1.62
11.55
118.86

I then threw in an ATI 4500 rpm converter:

1.55
11.33
120.03

I don't remember exactly what Phil's raceweight was... but I remember it was fairly light, so I reduced 200lbs off down to 3150 lbs.

1.531
11.12
122.16

I don't remember what your best is or remember what gear you're running, but the effects of the serious modifications are interesting. In a little bit, I'm going to run Ralphs set-up with the same assumptions and see what it kicks out.

I thought about a good apples for apples comparison of a 350 MR set-up vs Ralphs stock SR and came up with 3rd gen forum member Traxion, who has a very good running F-body that is pretty close to Ralph in a lot of ways.

They both are on 350's, both auto's, both have converters in the 3000 rpm area, both have ported AFR 190 heads, both have gears between 3.45 and 3.73, both are running hyd roller cams, both know what they are doing and are committed to running good et's, which is important obviously.

I think Traxion has run a best of 12.24 @ 112.52 with a 1.77 60 ft, but maybe thats been bettered by now.... dunno. However Traxion as per his webpage is at 3550 lbs, which is about 200 or so more than Ralph, thus with weight down, he would probably be right around 12 flat and maybe even 11.9, which appears to be about what Ralph is running in the summer air...... I think in street trim with moderate converters and gearing and a hyd roller cam, the SR and MR are really, really close.

But its all guess work..... any other opinions ?

later
Beach

 

interesting; here we go:

i had most of your specs in my system already, but let me confirm

350/MR/zz9/with heads flowing in the 250 range
sim yielded peaks of 435HP @ 6000 & 385TQ @ 5000 (+/- 300 rpms)

car weighing in at 2950 with 430 gears & 28 in tires with a th 350 shifting at 6000rpms and a 4500 stall

Sim yielded the following times

1.52 60ft
7.08 660
96mph
11.18 ET
121 mph

Then i enter the gear change from 2.48 to 2.75 and it actually hurt you times?? After looking at it a while i realized it was assuming more tire spin. so i went back and started again, but assumed crazy wide slicks on a grat track to simulate full hook. The results are shown below. Still the 2.75 first gear didn't do much, probably because it assumes you are only in 1st gear for under a second. Wow, don't take your hand off that shifter...lol

2.48 2.75
60 1.45 1.41
660 7.00 6.98
mph 96 96
1320 11.12 11.09
mph 120 120

 

Ralph,Beach & Jason,thanks for all the neat stuff.
Ralph,my TQ numbers are the same as the HP except peak at 4800.
I'am in 1st gear for what seems forever right now.The 2.75 will behave more like the ZF combo.Should shift into 2nd ~70-75 ft mark.
Lenny H who runs a LT1 with 3.08/4.10 with 26" tire shifts in 2nd before the 70ft mark,but definitely after the 60'.He is in the 1.56 area,if he does not spin tires.
The TQ numbers indicate that the MR is alot more torquey than what some people say.Remember ,this is a 350cu.motor.
:seeya
Phil

 

I went ahead and tried to set Ralph's set-up the same as Phil's and the results are:

Baseline: 3.45 gears, 3300 raceweight, 3000 stall, Ralphs estimated Torque curve based upon traditional SR's.:

1.635
11.72
115.84

I think this is close to what Ralph's best slip to date is in fairly decent air.

I then put in the 4.11's

1.64
11.71
115.78

Not much their as I think typicaly with long runners and gears. Sim backs this up. As a note, he's at about 6200 rpm going through the traps.

I then put in a Turbo 350 tranny gears.

1.630
11.717
115.10

SR didn't like that either. Lost mph, not sure why.

I then increased stall to 4500 rpm

1.57
11.62
115.20

Improved, but not like Phil's did.

I then reduced weight to 3150...

1.55
11.46
116.34

weight always helps

Looks like the MR really likes a lot of gear and the big stall, whereas an SR improves moderately. That would be a lot of compromising for less than 3 tenths in Ralphs case, but in Wheelsup case, I'd do it a heartbeat too considering the gains shown.

Interesting stuff. ... wonder if my sim is even close.

later
Beach

 

Phil, maybe we can get Beach to run that gear change thru his sim. Sometimes his is more accurate than mine and i agree, that it shows our shift points too early. it has me shifting right at the 60 ft mark, and i know its after that. that is why i bought it up...it had you shifting in .8 sec!!!! Must have figured you for a pro stock or something...lol anyway assuming you are in 1st for less than a sec, the sim is not going to show much for 1st swaps.

btw what were the weather conditions when you ran the 11.1x??? I assumed 80 deg, 40% hum and bar of 30.

Whoops, i just realized Beach posted twice. now i see what you were trying to do. I took a simpler approach. My race weight is around 400lbs more than phils (from mem). i the weather conditions i used for phil, i shoudl run an 11.82. subtract 4 tenths for weight. And maybe another .5-1 tenth for more stall so that would be 11.30...remember i said close...LOL. Here in lies my point...i dont know what else to do. we know more gear wont help the SR combo & i'm already factoring in gains from additional stall (but i don't think the Sr would like stalling as high as phils combo, so im limited there too. More cam??? i dunno, gotta be careful with this tuned system. I'm sure there might be a better cam, but i haven't seen any and it's got to affect drivablility. So where do i go?????

89vette, sorry we've taken this thread off on a tangent!!! Maybe we should go offline (email or start another thread)





[Modified by ralph, 3:53 PM 9/6/2001]

 

Ralph,

I really don't know how accurate this sim is... it seems to predict well for my set-up, but do I really know ?... no is the answer. But I like playing with it.

I'll try the gear change suggested above....

Whats interesting is what happens to Phils set-up when you add a lot of stall and what happens to yours per the sim.... Phil not only picks up over 2 tenths, but also picks up well over a mph.... where the SR only picks up .1 mph. Same with the gears, even though I have your HP peak fairly close to one another. I have your torque peak several hundred rpm lower in the band though. I had the parameters of the sim set identical such as pump loss, torque multiplication, gear efficiencies, etc... yet yours just doesn't like what Phil's likes.

I think both of you guys have set-ups awfully close to optimized, with Phil going the extra mile with the huge converter and gears and raceweight.

Phil what is your raceweight anyway... I thought it was around 3150 lbs... am I wrong ? And are you running a 4.30 gear ?

later
Beach

 

Beach,I'am running 4.30 @3150lbs.Remember,I added weight with the solid rear.Also,my SIM is like Ralph's in that I have to over tire the car to stop wheel spin.
Phil


[Modified by wheelsup, 5:50 PM 9/6/2001]

 

my sim does the same thing...maybe even more so. When phil swapped converter from i think a 3500 to the 4500, the sim showed him gaining quite a bit and it was within few a couple of hundredths. However it doesn't like too much converter for my car. it shows slight improvements up to about 3500-3800 and then starts to hurt it. Same thing with gear...although my sim likes a 3.73 best for my setup???? Like i said earlier, the SR is very limiting at this level. if it doesn't like more gear or converter what else is there? I'm not going to a th350 and giving up the OD. I can't remove much more weight without throwing out good stuff like A/C & head lights & other stuff i use. I could go slightly larger on the cam, but it's like the law if diminishing returns...more cam wants to rev more...SR doesn't!!! More cubes...well we know that works, right...but only to a certain point. 383s seem to peak the SR with larger engines showing only marginal gains (ie, my post on anybody running quicker than 11.2 with a SR).
Did you show any gains for Phils gear change??? with my sim assuming he is shifting in .8 sec....not much to gain there according to the sim.

Wow Phil, that rear added 200lbs??? nevermind my comment about getting close..lol We are only 200 lbs apart!!! i gotta rerun your numbers with that weight...i thought you were only 2950

interesting stuff





[Modified by ralph, 5:57 PM 9/6/2001]

 

Ralph,I also that to have a tranny crossmember fabricated that runs from frame rail to frame rail.It also has a driveshaft loop in the front and rear.The new steel driveshaft is also longer than the short alum. stock shaft.I'am running a heavier wheel/tire combo.
Who knows,I thought for awhile that I would have to place ballast in the rear to hookup.I have done some tuning on the suspension and I may need to install lighter coil overs in the rear.

89Vette,I know we have got off track with your original post.But,by the looks from the number of inquiries,alot of people are either finding this amusing or interesting or both :sleep: :crazy: :D
Ihope all this yada yada helps someone out there who planning their performance path.
Phil

 

phil & beach i just emailed you cause i thought we were pirating 89's thread, but you're right, this thread has 680+ views. i guess somebody finds this intersting besides us...lol

 

Ralph,

It might be our MAF that shuts down a well ported SR... Juilio was running DFI if I recall was easily into the 10's with a 406...food for thought.

I re-ran Phil's set-up with the known information.... baseline as he sits is:

1.528
4.536
7.080
96.98
9.262
11.106
122.10

I changed 1st gear from 2.48 to 2.75 it kicks out:

1.528
4.528
7.069
97.04
9.250
11.094
122.13

Small improvement...I think the 60 foots that are identical by coincidence and what is hurting the 2.75 scenario is that is begins its shift 43 feet out (All of this is based upon a 12" rollout), and completes the shift at 52 feet out assuming a firm shifting auto and 6200 rpm shifts. However, the 2.48's begin at 58 ft and completely engages in 2nd gear at 68 feet. Thus the 60 doesn't appear to improve, but in reality the end result is a hundredths improvement.

As a note, I re-ran your set-up fully optimized similar to Wheelsup and at a 3150 weight, and played with a bunch of different converter selections and 4200 rpm seems to offer the best performance... anything higher and you slowed down... however the difference between 3600 and 4200 was 2 hundredths. This brought you down to 11.35 @ 118.33 You got quicker all the way up to 4.11, but the differences were so manute, I don't recommend you change... difference between 3.45's and 4.11's was 1-2 hundredths. Not worth it obviously.

I'm going to try my 383 as soon as I have a chance...

Phil, why did you go to the 9" rear end ?? Did you crapon a couple of spiders in the D44 or something ?? So far those 3.45's you sold me are holding up great !!! Probably have 50-100 1.5x 60's on them now and another 200 low 1.6's and zero problems. (knock on wood)


btw, I know we've talked about it before over email... but I still have no clue on how you got so freakn light.... I'd give Ralphs 1st born to get down to your raceweight !!!

later
Beach

 

One Last Simulator test...

I took my set-up which has ran a best of 11.55 @ 117 and put in 4.11 gears, 4500 rpm converter, 3150 raceweight, 28" tires and it spit out:

1.476 (I like that)
4.458
7.003
96.89
9.186
11.029
122.14 mph.... most of this came from the reduction of 350 lbs... too bad I can't actually get down to this weight. The difference between the 3.45's and 4.11's was 2 hundredths... when I tried Phil's 4.30 gears I slowed down 3 hundredths !!!

Food for thought.

later
Beach

 

[QUOTE]...but you're right, this thread has 680+ views. i guess somebody finds this intersting besides us...lol

Hey Ralph:
:yesnod:

The old NMP debate... Superram or Miniram

 

hey Mr.G...how are you??? Like old times huh.............all we need now is for Dennis and Tobin to join in......

 

I probably account for about 20 of those views, but I don't post at work.

I have spent a lot of time trying to fix the inherent problems associated with the MR, as I had done with the SR prior. I have cut, welded, drilled, machined, ect on the MR that TPIS would have a hard time recognizing it.

I would be interested to find out what the sims say about the combo that I am setting up. If someone has some spare time.

87 roadster, 3620 If I remember correctly (200# of me)
408 ci shortblock, 9.5:1 static
AFR 210CP (300 cfm @ 0.550 lift)
SR cam (236°/244° @ 0.050, 622/630 lift)
MR with flows that exceeded the head, 58MM TB
11# boost @ 6000 rpm (prob 13# at shift point of 6500 rpm); intercooled
ZF 6 spd, 3.45D44 fully cradled and reinforced
26 x 10 ET drags

also as a option, I have a fully staged 200 shot NOS system. I would like to know on the motor without the gas, then maybe with the gas. Car used to turn nice 1.6 sec 60' times. Have a lot of problem w/ spinning, another reason switching to the MR.

BTW, to comment on an earlier post. I have changed the fuel system considerably, though TPIS states that the 0.22" ID of the lines provided are enough to support 550hp. Not on my motor!!!

Thanks for any insight

Aaron

 

Yeah, I think we've all gone over this stuff a bunch of times.... but we've never discussed big time 4500 rpm converters and very steep gears like this... it is interesting, you start to learn how the comp eliminators wrangle so much et out of almost stock motors. I've read about set-ups with 350 HP running high 10's, low 11's with 5500 rpm converters, 6.14 gears and 30"+ tires.... lord knows what suspension tricks they know. That same motor they're running could be installed in a Minivan.

Its tempting to do some of these things, but even things like weight loss, which seem simple... are not, they too cost money and lots of it, carbon fiber hoods, lightweight doors, etc... are darn expensive. When I had my rollbar put in and everything was tore apart, I took the carpet and sound deafening stuff out of the hatch area and drove her around the block... wow !! that sound deafening stuff definitely works, I immediately put it back in. It did feel heavy though, not sure how much though, should have weighed it while it was out.

Beach

 

Your not pirating my post. Keep it going, I keep looking too! :lol:

 

Aaron, I ran it on the engine simulator, I had to assume a few things, and I came out with 714 HP @ 6400 rpm, and 670 ftlbs of torque.... I have no clue if this is right, Ralph is pretty good with the engine sim, maybe he will run it. I used this curve and put into my Dragstrip modeling program, which spit out a 1.70 60 ft -- 10.14 @ 141 mph, with the 200 shot it showed 9.51 @ 149 mph.... I didn't bother playing with driver options and traction to knock the 60 ft down close to where it belongs because I have no idea how accurate this is. But if it is... Wow !!!

If Ralph gives me a good torque curve, I can run it on the dragstrip modeling program and give more accurate #'s for the expected performance.

later
Beach