This question I have gotten two completely different and opposite answers that I am just lost now.
Say you are 60 footing pathetic.. 2.3, 2.5, etc. Same mph 116.6 (cough yes these are my car's examples, and yes cough I did manage to rush from a job interview forget my wallet, ID, money, after changing out of my suit, figure it out 10 minutes from the track, then manage to forget to hang my wiring harness so it doesn't drag-- guess what, lost lights, said hmm, lost trailer brakes.. pulled over.. wiring harness was doing a slide along the pavement like my safety chains (I cross them and they are still too long..) so I am driving back down from the track with no brake lights on the trailer, using hand signals, ready to wet myself if I get pulled over with no license, etcetc.. ok I am getting off topic big time.
I have been told two different things: You can spin for quite a while or get on it really easy, and the MPH will be there even if you go slow or spin.
or 2: a heavy car, moreso than a light one, will play "mph catch up" and show a worse MPH than it would had it 60' with a 2.0 or under.

Since it has been raining and stuff every wednesday (only day I can get to NED), and the day I was on my way up was great weather.. 48% humidity, 70deg, nice, sunny day... I am going to chassis dyno the car again to get more info on converter slip and whether it is better to let the engine rev to the 6800 it needs to go through the traps (no rev limiter), or same MPH bouncing off the rev limiter (w/ 6600 chip, revs max at 6500) or shift into .78 and drop to 5000ish rpm and see the shift is a better idea than revving my engine to where its not supposed to go.
I am gonna let it run on the chassis dyno with a 6800 rpm chip in it, or maybe no chip and just watch that tach carefully. The engine dyno/cam swap guy never took the thing over 6200.
I'd expect with my wide lobe separation, big duration cam, (massive waste of time and $$ at this point) that it would rev out longer and make better average power.. but according to the engine dyno guy the thing is done by 6200ish.
I wish I had chassis dyno #'s with the same converter to compare.

Ok.. I will write a 20 page manual on how to be angy at your cam if I don't stop now.

the original question was about 60's and MPH...
heh.

matt

So many questions about drag racing do not have concrete answers and IMO this is one of them. Every combo can respond differently in that what might be true with yours may be completely different with another. I personally have a combo that I fully expect to pick up 2 mph once I establish good traction no matter that others say I will not. I say this for mine because of the experience I have with other combos that are similar.

I just want to squeak 120mph hr out of this combo and something is holding me back, just need some track time to figure it out.. I hope anyway.
That or I got 25-35hp for a shade under what a blower would have cost.. (including fixing the transmission though..)

matt -- I have a new digital camcorder-- expect some footage as soon as I can.

Relax, everything is going to be okay. More than ever you are experiencing the fact that the track is the ultimate dyno

No mystery here, simply that neither the car or driver is optimized for the task. With suspension/traction issues and a driver needing more seat time your results can seem confusing. Remember that all predictable results, 60' vs e.t., are based on more or less well sorted car and driver combos. I'll repeat what you have already heard: you need to go to the track during something other than test-n-tune days - most tnt track prep is just keeping things clean, not much adhesive. Just a guess; with 4,020 lbs, lots of hp, and 2.3-2.5 60' times you are probably experiencing wheel squat: where your tires are being pulled up towards the frame, rather than anti-squat where the tires are being pushed against the ground.

Simple physics to the rescue: heavy objects are hurt more on acceleration with slow take offs. Heres more: let's say you cut your 60' from 2.5 to 1.5, then that means the next second gets to be used at a higher mph.

You have a Gear Vendors box on your car? At least that is where I think your mention of .78 comes from.

Your engine dyno guy is not likely lieing about the after 6,200 rpm power drop off. That does not mean that you won't be faster by shifting at 6,800 rpm. Part of the deal on shift point rpm has to do with the rpm that lets you start the next gear (the idea being to have the highest average power, or power under the curve, being laid down). I don't remember if you have a solid cam, if so then 6,800 rpm is no biggie unless the wrong spring choices were made.

I don't think you can blame your cam for the 60' times. If your cam is torque biased, then you should use that to your 4,020 lb caboose's advantage. Heavy cars need torque off the line, you need a suspension or traction solution, and possibly a different stall speed.

Thomas

It's a solid roller.
There is a chassis dyno sheet with a stock 12" converter that said I made 426 ft-lbs max and 461hp max.
The cam swap and engine dyno guy said that (and after hearing I think wolfpace say so many times solid rollers need spring, although I think Tom Baird is running similar springs to mine with his SR) once you start going past 6300 or so the lines he drew on the retainer and on the valve lock showed that the valves were starting to move a tiny bit when the revs got past 6300. I've had it bouncing off my rev limiter at 6500 so many times I can't count, and at the track I pulled the chip out and did a run straight through at 6800rpm and did the exact same mph.
I am going to head up at some point with my ET streets (the little ones) and my wallet (unlike last time) to see if I can get a 2.0 60' to see what is actually happening. I know I can pull 1.8 60's at LVD on saturday test and tunes, so a 2.0 at NED if I get there early shouldn't be impossible (but I have never been able to do it, but I see other people doing 1.6's and 1.7's up there on Wed's (few and far apart) so its me not the track, althought the track isn't helping).
For what its worth, my converter feels less "stallish" than it did behind the old motor.. I assume flooring it on a chassis dyno with the kickdown switch pulled and putting the car into 3rd manually before flooring it will give me the info on exactly what stall speed my converter is, or do I have to test it from a dead stop?
It's just an idea I have to try dropping the engine back to where it is making more torque, it will only take one or two runs at the track to see if the shifting idea has any merit or whether I am too far into the run for it to matter..
This wed is crossed off, weather is going to be bad. I suppose it should be an indication to me that track prep is not a #1 priority on Wed/Fri nights at NED because slicks are not allowed period.. only DOT slicks..

matt

Unless I missed it you didn't state what head you are running. A big port motor with that cam will run real good to 7500 I am assuming you have an oval port motor. That would explain the lack of RPM but the thing should make some serious torque. Is it possible you have a junk convertor? I have been stung that way in a new combo that I didn't have a base line.

Originally posted by Mike Feudo:
Unless I missed it you didn't state what head you are running. A big port motor with that cam will run real good to 7500 I am assuming you have an oval port motor. That would explain the lack of RPM but the thing should make some serious torque. Is it possible you have a junk convertor? I have been stung that way in a new combo that I didn't have a base line. Oval ports are not the reason why it cant RPM

Nope..

320cc intake runner Dart Rectangular Port Heads...

I can get the #'s off the head if you want..
They have been milled to 116.5cc combustion chamber.

I've been told they aren't the greatest heads period and thats my problem, but I've also been told they made fine low end torque for a rectangular port head..

here is the engine combo: (ripped from my website)

2 bolt block original LS5 GM casting

* Eagle +.250 Rods
* SRP Domed Pistons 10.14:1 Static CR
* Stock GM Forged 4.00 Stroke Crank
* Comp Cams Solid Roller 287/291 256/260 .643 lift (installed at 104.75 ICL) 112 LSA
* Isky Red Zone Lifters, Comp 933 Springs
* Lunati Titanium Retainers
* Crower SS Roller 1.75 ratio roller rockers
* Edelbrock Performer RPM Manifold
* Holley 750DP with 850 Baseplate, choke horn milled
* Over-Sized 2" primary hooker super comp headers

There is nothing outstandingly "wrong" with your engine - start looking elsewhere for targeted areas of improvement.

I'm just going to keep harping on suspension/tires until you do something about it. Might be as simple as the low profile 17" tires being totally wrong for drag racing You have some good components, I'm saying that it is probably not well set up. My '65 makes very similar power, and with ~ 3,500 stall the last track visit saw a 1.57 60', and I'm expecting even quicker 60' times as I dial it all in.

Thomas

I was on my way to the track with the ET streets on.. and forgot my wallet. Haven't had a sunny Wednesday since.
There are some good parts tossed in there and my 17" street tires are not good at all for dragging, but I will not cage the car, so going to a 28" drag tire is a waste of money, so I have to stick with my 26" ones. I am trying to squeak 120mph out of the thing- it was my goal.
I'm just not sure its there.. need to get back to the track for more shake down runs but weather this wed isn't looking too hot.
I am not in the mood for any serious changes to the car, but I'm still scratchin my head for that 120 mark.. I thought this would be the combo.. or atleast not 4mph off.
The car has just a regular boxed arm rear suspension, I have an airbag I am going to reinstall (put my old stiffer springs back in because the rear end was too low..).
The only thing I've considered is that this engine could(?) run fine on more compression, but I am not sure about that and whether 10.14 to 10.5 is even worth the hassle. (93 octane).


Matt

Well, if your goal is a slow e.t. and high mph then more hp is the only real answer.

Man, you sure are making it hard on yourself.

Thomas

Its been my experience that the more you spin the higher your mph will be,sling shot effect I guess(more time on the track) :confused: If you hook you get moving quicker and have less time to get to a higher mph. Most of us arent after mph though, we're after e.t. :D

Basically yeah..

I have personal issues with cutting up an canadian built, documented LS5 that I have all the original parts for (heads, manifold, exhaust manifolds, air cleaner, etc), the rest I can buy.
It will be atleast 4-5 years before I can buy a dedicated drag car because I already have a ton of bucks into this car and a truck to pull it.
I am thinking, I did some math.. It might not be correct.. but.. I get 8.3 DCR with this thing @ 10.7 CR.
A .020 steel shim head gasket gets me 10.5ish.
(I am using the DCR calc, the only numbers I am estimating are the head gasket bore).
I'd be curious to know if this thing would run on 93 pump @ 10.7. The thin head gasket and 1.5cc's off each chamber nets me the 10.7..
Maybe a project for next winter.
When I bought the car I didn't know I was buying something special. When I figured out there aren't too many left, I made the decision to never hack the car up for a cage.
So yeah.. more power... I just thought this combo was enough "more." Thats all..

I know a nice 60' would give me a decent ET, and even with a pretty regular suspension on so 28*11.5 ET Streets I don't think a 1.6x would be a long shot with a few practice runs. But I'd be booted off any NHRA track and I think with a 1.6 an IHRA track (11.50) too.. so I was gonna give it a whirl with my 26" tall ET streets where I have gotten a 1.8 60' (with different rear springs and my airbag installed, although I can reinstall the airbag in a couple minutes), I figure I would get a 1.8-2.0 60' (with some luck...) and try my shift thing to see if I can scrape 2 mph out of the combo.

I I'd like to hook hard and have fun, but I am not compliant with safety regs and I personally don't think hacking up a documented LS5 is worth it when I can buy another car in 5 years and save up for a blown/turbo'd 540..?

Matt

Have you done any serious tuning? Like you said it should MPH a lot better. It sounds like you checked the valve springs how about the ign., fuel? Like my first post said torque convertors can really be a problem when you have no base to work from. Your heads are not bad by any means I went 123+ with an 850 in a 4000# car with a set of stock big port heads. Your heads are far superior to the 840s I was using.

Mike I was told by the shop that did the cam swap and engine dyno to invest in an A/F Meter as soon as I can, but with Tom B's electric to carter 172 test I am unsure I am sucking the bowls dry like the shop suggested I may be.
the car was tuned pretty extensively on the the dyno, and we found it could care less about timinging.. anywhere from 34 to 40 degrees gives the same hp/tq #'s.
it's very sensitive to jet changes, and I was given a set of recomendations for weather conditions and jet sizes.
I haven't had much track time with it at all, due to my stupidity and bad weather.
Unfortunatley I am a comptuer generation person and tuning to me involves laptops and not accelerator pumps.
The shop milled the choke horn and played around with the jets, air bleeds, squirters, etc, I was watching the entire time.
I am going to proably pop my air bag back in and head to the track with the 26*10.5R15 ET Streets and pray I can hook at NED and see if I can get a baseline.
I hear alot about just having a junk converter, and unfortunatley this is the only converter I have ever run the car at the track with. It was originally ordered with a 2600rpm stall, then I sent it back for a re-stall for 3400, and then had it inspected when the tranny guy found metal shavings inside my trans that clogged the filter and smoked tranny because of lack of line pressure. The tranny guy swore up and down that there is no way the metal he found came from inside the trans, so it had to come from somewhere else, converter company swore up and down the converter was fine.
I need some more time at the track, but the jetting and stuff I have all written down, and the motor seemed to be well tuned on the dyno in realistic conditions.. my headers, my x pipe, my exhaust, my mufflers, my tailpipes, alternator, water pump and air filter, 88* room temp..
So I just need to play around with some stuff..
I know i repeat myself every post, but I did an x-pipe and went from a 286 @ .006 230 @ .050 .639 single pattern hyd roller to a 287/291 @ .020 256/260 @ .050 .643 (cam card specs) 112 LS installed at 104.75 ICL and gained about 35hp, ,maybe 30hp, according to track mph.
The tranny guy who inspected an repaired my transmission was not the guy who built it the first time. The converter company was the converter company that built it.. It could be the converter, but thats alot of hassle to go through.
What do you mean by "serious tuning?" Sorry I seem like such a dimwit here, but like I said.. I'd be alot more at home behidn EFI fuel maps than on a workbench with accelerator pumps and fast idle cams, air bleeds, transisiton circuits..

I am rambling..

matt

Matt, You should be able to run 10.5 compression easily with the Aluminum Heads. If no real good head porter has touched these heads you have a ton of power left in them as they tipically only flow what the factory square ports do when stock. Ported they can flow 380+ CFM and should pick up a real 60-80 H.P. or thereabouts (Mike Stark at CFM ports these frequently). Your converter could be hurting you but it is probably just lack of traction. More bite will probably slow the trap speed some but your MPH isn't too bad as is. Might not go down but probably won't go faster without more power. I wouldn't cut up a LS5 car either (pi** on NHRA), I've made dozens of 11 second runs and never broken anything except one "u" joint, Behind a healthy 454, which had a grease sert in it. I did have a driveshaft loop and think thats a good idea but a roll bar isn't necessary in my opinion. (Safety Nazis over at NHRA are satisfying their insurance companies). This is the same mentality that thought they could slow down the top fuel cars by limiting the gear ratios to 3.2. Just made the fuel cars design better fuel systems and overdrive the blowers more.

Harold,

The site doesn't list your email. Want to shoot me one at the one the site lists for me?
I'd like to know some more about this but not tie up the group if possible.
I only have limited info on the heads themselves as i bought them used from the first engine builder, and I to be honest probably could not tell a ported BBC alum head vs a non ported just by looks.
I shot an email over to the guy who did the cam swap to see what he had to say about noticing any porting/cleanup.
If we are on track here, 10.5-10.7:1 and some good port work might net me 50hp and enough to crack the 120mph mark in street trim, w/o a power adder (my goal!). I can see where a certain person is coming from though.. if I am only using 6200rpm, then for heads.... and he told me this too.. (but also everyone else... heh)

Matt

Matt