[garrity455]

Hey guys, most of you know I put a new combo together this winter, I had a post about the engine dyno results. Well we made our first runs today. Air was pretty good, DA around 900 feet.

We had an 11.53 at 114 and an 11.43 at 114.9.
60' of 1.55 and 1.53.

Car seems to leave real hard, but mph isn't amazing.

I have links to a video of the car just sitting then a few time slips for the day and a few shots of the car.

3800 lbs with driver, 79 transam.
3.42 gear, 10" continental converter, th 350.
Holley 750, performer rpm.
280 cfm 87cc e heads. 10.2 to 1 compression.
240/246 hr cam with 109 lsa.
3" xpipe reducing to 2.5" ultrflo, 2.5 tailpipe and splitter.

Launched about 2200, shifted off 5300 light, trapped about 5300/5400.

Robbmc pickup, filter and fuel pump.


http://www.youtube.com/watch?v=9TyQP...e_gdata_player

http://s1208.photobucket.com/albums/...er_media_share

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http://s1208.photobucket.com/albums/...er_media_share

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[ponjohn]

Garrity-

Car sounds good.

Is the cam a custom HR using comp lobes?
What lift and lobe sep?

Think it might need more fuel? ( I don't know anything about the Robbmc )

[grandville455]

Sounds good mike!... Maybe u needed to shift it higher? did u try that? May need more than a 750 too. What was total timing at?

[Nicks67GTO]

A couple questions...

Are you running power brakes?

Are you using the new D port E heads?

Double pumper or Vacum secondary?

[garrity455]

Hey guys, I misquoted the cam. I went to hft 240/246 last year. The hr cam is 242/248.
It is comp cam using lobes 3018/3039, on 109 lsa.

Lobe lift is .3660/.3630. I think 600 lift with 1.65 rockers.

Yes, I do wonder about fuel supply. No noticeable break up, but maybe a little something there?

Darby, we didnt raise the shift points any, which could certainly help. Peak hp was around 5500 on engine dyno. But with stock crank and rods, I don't want to shift too high, even of we give up a little performance. I know we still saw 5600 at times between shifts.


On the engine dyno the 750 ran step for step with the 950 they tried. But if I knew a 950 would run same ET with more mph and less 60' I would take it we were running 37 for timing, but I may try 34 or 35 next time out, just to see what it does.

Yes, I run power brakes. I drive the car to the track and drive/race on m&h drag radials.
No, these e heads are over 10 years old I believe.
Double pumper carb.

Actually after the last run, the car died, upon restart we noticed a whistle. There was a vacuum leak on the carb gasket, and we tightened down the carb a little more and the whistle was gone. Not sure if that impacted the run or not.

[ta man]

Good going for first time out.with a new combo...Hook up a fuel pressure gauge to make sure your pressure isn't dropping.I like your 60fts what is your suspension setup?Your exhaust looks and sounds familiar!

[steve25]

The stock fuel lines on that car can in no way shape or form feed the amount of fuel that motor is calling for at full throttle and at high revs, you may very well read good pressure, but the needed volume will not be there!

Your high rpm break up is a clue to that, and the next thing to break up at high revs will be motors bottom end!!!

Also your carb is a bit on the small side cfm wise and if you are running just one Holley blue type fuel regulator be informed that they are a flow restriction and can just pass enough volume to feed that 750 with that size motor.
If it where me I would step up to a better one.

[Cliff R]

Good runs Mike. Great 60' times. MPH is WAY down for the power level. I'd look at fuel delivery. I would have thought at 900DA and those kind of 60' times you'd have went low 11's at 119-121mph. How much head wind? ET and MPH at the 1/8th mile?.....Cliff

[grandville455]

Mike I was just looking at something else too, I think u said u were using 28" tire? You look to be slipping almost 700 rpm on top? That could be a player in your lower mph too

[torqjunki]

Very nice Garrity. Also think advice given here is very good. I have run a 750dp and 850dp with very similar combo as yours with no change in ET. I think if you had a combo that would run up to 6500rpm, you would need more carb for sure. As far as the fuel system, no two cars seem to react the same with similar set-up. The 7.39 1/8th mile in my signature was run with stock tank, pick up, fuel line and robbmc 550 pump with vapor return. Think I went close to 94mph on that pass. Although I had dialed in the carb using a wide band, I picked up a lot of et at the track that night by going back to the original jetting supplied with the quick fuel 850 carb. Needed a little more squirter as well, and a bump from 38 total to 41 deg. IIRC, jetting went from 74/82 to original 76/84. THis is pretty close to sea level with 93 octane pump fuel. Very nice combo man.

[ponjohn]

Originally Posted by garrity455

Hey guys, I misquoted the cam. I went to hft 240/246 last year. The hr cam is 242/248.
It is comp cam using lobes 3018/3039, on 109 lsa.

Lobe lift is .3660/.3630. I think 600 lift with 1.65 rockers.

Yes, I do wonder about fuel supply. No noticeable break up, but maybe a little something there?

Darby, we didnt raise the shift points any, which could certainly help. Peak hp was around 5500 on engine dyno. But with stock crank and rods, I don't want to shift too high, even of we give up a little performance. I know we still saw 5600 at times between shifts.


On the engine dyno the 750 ran step for step with the 950 they tried. But if I knew a 950 would run same ET with more mph and less 60' I would take it we were running 37 for timing, but I may try 34 or 35 next time out, just to see what it does.

Yes, I run power brakes. I drive the car to the track and drive/race on m&h drag radials.
No, these e heads are over 10 years old I believe.
Double pumper carb.

Actually after the last run, the car died, upon restart we noticed a whistle. There was a vacuum leak on the carb gasket, and we tightened down the carb a little more and the whistle was gone. Not sure if that impacted the run or not.

I had the same problem with a carb gasket. I got a reinforced gasket from Shaker (on PY).

[torqjunki]

Just noticed the 4000+ converter. That is getting you the killer 60ft but likely hurting your MPH. Not sure of the condition or usage on that unit, but for a street car that is regularly driven, I feel you could run just as strong and have much better feel on the street with a tighter 10" unit. Good call Darby

[garrity455]

Hey guys, here is the time slip.

As for fuel supply, two years ago I went to the Robbmc 1/2" pickup, 1/2" braided, and the robbmc fuel pump. I ran his regulator for a little white also, but I blew the diaphram out of it twice, and now have a holley regulator on there again.

I actaully have a fuel PSI guauge in the car, so I will check that out next time I run. Too many new things going on.

I don't have any high rpm break up, or break up of any kind. The car seemed clean all the way down the track, except for shutting off after the last run, before retightening the carb.

There was decent head wind yesterday as well.

I will get back out and try some different timing, maybe try 34, or 35 rather than 37.

I am going to keep the shift points down, just for peace of mind. I don't have a roll bar anyways.

The 10" converter was actually just custom made last year for me. Based on my gearing, tires and weight etc.. although I did have less power then.

I will still be driving the car the 300 miles to Norwalk this year at 70 mph

The suspension is all stock as far as shocks and springs, but I do run the SSM traction bars on the car.

Actually my buddy that I got these heads off of, is going to send me his Holley 750 HP to try. I know it is still a 750, but the HP is supposed to be a little better I guess, and he had it tuned pretty well with this heads last year.

I will see if that makes any difference.

I have to say, my goal for the car was to be able to go 11.3s in great air and so I was pretty happy with the car for the first time out. I certainly think I can hit 11.3s this year. So overall I was pretty happy with it.

I will certainly keep you guys up to date if any of my changes make any real difference.

Thanks,
Mike

[grandville455]

Mike i say its falling off cause of slippage more so then fuel,but yes look at the gauge next time out for sure.Using your 7.19 1/8 th it takes a correction of 1.59 to get to 11.43.. usually u see 1.56 - 1.57 as a better indictator. My car 6.89 1/8th using 1.575, used that in the grandville too it comes to 10.851 It ran a 86 with a zero. I also think those eldey heads like more timing not less. Very nice runs for off the trailer!

[ponjohn]

Peak torque was made at what RPM?

[Cliff R]

Head wind plays a big role here. I'd make some additional runs where you aren't running into the wind without a lot of changes and see if the MPH improves some?

MPH isn't down that much in the 1/8th mile for the 60' and ET, looks like it's slowing down more on the top end, which could easily be fuel delivery and running into a strong wind on the top side of the track.

WAY back when I was trying to run a mechanical pump, and electric pumps feeding mechanicals, etc, my car felt fine for all runs, just didn't MPH that well. Sumping the tank and installing an electric pump behind the tank, and 8an lines/fittings everywhere netted a solid 4mph increase with no other changes.

If you want to try a well set-up 850cfm carb, I have one collecting dust above my workbench. I only keep it around here as a dyno "mule", or a "loaner" on occassion.....Cliff

[garrity455]

Hey guys.

The current combo showed peak torque at 4200 and peak hp at 5500 on the engine dyno.

I may chassis dyno it as well, just to get a comparison of in car with power steering, stock fan, alternator, mechanical fuel pump, drivetrain etc..

I certainly intend to go out and race it again without changing anything.
We actually made 3 runs Sunday. 11.59, 11.53, 11.43, with better 60' and mph on every run. We didnt make a single change during the day. The weather changed, and I guess the vacuum leak got a little worse until we found it after the last run.

So it will be interesting to see what we find next time out.

I know the edelbrocks always seem to like a lot of timing, but if I find I can run 34 or 35 degrees and not slow down much, I will probably change it.

After I get everything all settled with the current parts, I will try Corey's carb next, and then I may take you up on your offer Cliff, thanks for the offer. Maybe I will even try it at Norwalk.

As for the converter I will say this. I made that change before Norwalk last year. After a day of running slower than I thought it would, I actually put my old tighter 11" Coan back in the car at Norwalk. I slowed down another tenth then. Came home, raced it once more like that, then put the new 10" continental back in. Next time out picked up the tenth again. So it didn't seem to hurt mph last year.

But as I said, I will get some more baseline, then let you guys know the results of any changes I try.

And Darby, yes the 1.575 is always pretty close for both my dad and I normally.
And that would have my 7.19 to a low 11.3. So I will keep working on that.

My dads car went 9.63 this weekend, so he is running well.

[Cliff R]

Mike, all of the E-headed engines I've built here ended up making best power in the 37-41 degree range. They were all zero decked with well chosen cams for the compression, etc.

No need to "grind" up the engine with a high shift point, it will pick up a few hundreths shifting up near 5500-5800rpm's, but why stress the assembly any more than needed? It's doing fine for the first outing, and will slow down a bit anyhow as the hot/humid weather moves in for the summer.

There is NOTHING way off the mark with your carb, or the converter, or anything else. You can find a little improvement in just about every component if you want to chase it hard enough? Also consider that making a lot of changes may not improve anything at all, if you are at the limits of the fuel delivery system. How many times have we seen that deal played out on here, folks tuning all over the map, then making BIG gains once they start keeping the carb full on hard runs?

I'd try to get some good runs in before things heat up, so you can fine tune and get the full potential from the combo. Once the heat moves in, it's going to slow up a tenth or so for every 10 degree increase. No need to drive yourself nucking-futz trying to chase that deal to death, just drive, race and enjoy it. I pushed my combo pretty hard when the engine was first installed to find it's potential, knew it was EASILY good for low 11's, even in the heat, then just backed off of it, detuned slightly, short shift, and have enjoyed in imensely for 3 seasons now........Cliff

[grandville455]

Mike
I still say its the convertor why your down on mph mostly, I have had a car that is as areo as a bus ,lol and into a wind i only lost maybe 1 -1 1/2 mph? Your converter is showing 12% slippage according to wallace racing. That is a ton! 3.42 Gear is not going to be enough for a 4000 stall convertor, If u have a chance to try some smaller tires it would help put some effective ratio in and tighten that thing up. I say your biggest gain is still there, all one has to do is look at the above number's and see it

[Cliff R]

The carb is a tad too small, fuel system most likely maxxed out for the combination, tires a little too tall, and not quite enough gear. A tenth improvement at each point puts him in the high 10's without touching the converter. It's a very similiar combo as I'm running, certainly not "optimized" anyplace, but fun to drive and will easily run under the legal roll bar rule at will.

My own combo pushes right up against the converter at 5000-5100rpm's on the top end of the track. I've ran up near 121mph and down around 116mph and it's always pretty much in that rpm' range pushing against not enough gear for what I'm doing.

I swapped in 2 prototype converters two seasons ago and IMMEDIATELY picked up in 60' and the engine revved a couple hundred rpm's harder on top end with about .5-1mph loss over the "tight" 10" converter I normally use. Pretty much a "wash" in ET as the quicker 60' was offset by giving up some top end charge. I really needed more gear/shorter tires to make the converters work like they were intended to.

I wouldn't touch the converter, some additional fine tuning, possibly a larger carb and electric pump behind a sumped tank and he'd pick up considerably, IMHO......Cliff