65 Gran Sport -Q-Jet, Manifold and Tom's rockers comparison race results

Hey Bob!

Having driven the 3.90 geared car to work now quite a few times and not dying of an earache, I'm rethinking my stance on gears....the 3.90 rear end is actually a 8.2 67 Buick GS rear, so I may just take that out and throw it under the 65 when we get the new engine done...

If I really need to go anywhere, the Pontiac still has 3.08's in it....

So now I need to collect parts to get these rears all set up and bolt-able in-able....if I'm right, a 71-72 4 door th350 driveshaft will work putting the 8.5 under the 65, and I have the th400 shaft for the 71, and a 70 GS shaft is under the 71 with the 8.2 now... If anyone has any drum brake hardware lying around, let me know what you want for it - the 3.42 rear is bare, but I do have decent iron drums and some weak 70 GS rear springs.

If I do it right, I should be able to put the 3.23, 3.42 or 3.90 rears under either the 65 or 71 in a half a day, and I can mix and match as the mood strikes me. They tell me an 8.2 wont live long behind a 455, but the 3.90 axle seems perfectly happy there, and has been for some time...


Tom - Did I mention I have a 1000 CFM Thermoquad that came with my 73 Stage1? I've been down on TQ's since a bad experience with a 1980 Police Package Gran Fury 360, but hey...???

 

That's awesome Rhett!! Great job to both you and Tom! Look forward to the day that I get to meet both of you in person. One of these days I'll get up to the east coast and hopefully have the GS in tow so we can run'em down the track.

Keep the updates coming Rhett, this is good stuff!

 

Thanks Johnny -

I'm headed back up this weekend, probably for the last time this year. All that I changes was one of the governor weights. I went from a 10 oz weight to an 11 oz - should bring the shift point back down a couple hundred RPM to maybe 4800 and give me back a 10th. Time'll tell. Weather looks good, a DA of just about sea level and cold! If I can hook, might just break into a new best ET.

 

under the rules can you put rosin on the tires... ???? we used to do that.... :Brow:

 

I'll do that for you!!!! LOL


Tom T.

 

Rules? What rules?

I wouldn't even know where to get rosin...but I've seen pictures of it being done.

I imagine the track would have something to say on that - get all mixed in with the VHT they lay down and make some kinda witches brew, right there on the starting line....

 

It is a white powder,, you get at sporting goods stores... put it on the tires not the pavement.... :Brow: wipe the tires down with it , using a rag ....
:grin: if the rules dont forbid it , then you can.....

 

While as that's a great idea that I don't see many people trying, traction is the one thing I got plenty of. I'm more concerned with getting that half a tenth back on my 60 foots and shifting where I keep the kettle on the boil, so to speak.

Also, since traction is good I want to experiment with flashing the converter some more...I tend to load it at about 1800 -2000 RPM and let the car walk out hard before I stomp it. I mean literally 3-4 feet and I'm on it. Tom had good luck just above idle and flashing the thing up to who knows what RPM, I couldn't get it to do what he did.....more trial and error necessary.

 

The fact is that any normally aspirated motor has used up its available intake tract air flow at the point where the peak the torque number is made and also any such motor will make rpm the fastest in the motors torque band where the motor is within 30 % of its peak torque number.

As you stuff in more cam to get more air in and out of the motor you make this torque band go up higher in rpm and you make it smaller also in terms of how wide it is, so if you do not make other changes to the car to complement that your improvements in ET will be small!
if someone would cast up or cobble up a single plane Intake with a 20 % runner expansion rate then current top running nail head guys would pick up a ton of improvement!

 

Steve - I'm only half following you....

What you're saying is true about max torque occurring higher in the range. I didn't change the cam, but the rocker change gave me more lift..I'm gonna get this wrong probably but .060 on the intake and .080 on the exhaust. After that change my peak torque moved from 2600-2700 to 2900-3000 as measured on my g-tech meter. But as I look at the RPM graph, the rate of rise hasn't changed from before, and it's the same from launch all the way through the shift point (2 speed). It's also the same from pre-rockers, to post...I've changed shift points, etc... but the graphs run parallel - the rate of increase hasn't changed.


The black and green are from last week, the red and blue are from 2012 (I know it's tough to read, and the ET's are wrong for all) . The RPMs aslo show we are hitting the converter harder off the line, no matter what technique we use.

We have gone as far as we can with the intake, the flow numbers are posted in another thread somewhere. And the 800 CFM Q-jet showed tangible ET gains. I realize the gains from all of these changes will be small on top of stock heads and exhaust manifolds. I might just have taken the stock long block as far as it will go in it's current, tired state - short of headers or open exhaust (which is something I could still try)

Steve - do you have any suggestions other than an intake swap?

 

Rhett, the higher lift didn't change peak power, its the more duration you get with the rocker arm ratio. going from say 1.6 to 1.9 ratio can give you maybe 4 degree more duration. thanks for all the testing and good info.

 

In actuality the duration does NOT change, as everything remains the same. What is changing is the effective duration when compared to what it DID have. This can be 20* more + or - a little. This is where the actual gain is. So no matter what cam you have in there the effective duration will ALWAYS be higher, but the REAL duration remains the same. I wonder what the effective duration of my friend Bob's cam would be as it started out as 284*/284* @.050" I & E.


Tom T.

 

Umm, your both right.

For clarity; Seat duration does not change. Duration @.050 increases by a few. Duration near max lift may increase by 20*.:bla:

 

I'll add some more info here...
I measured and plotted the stock cam lift with stock rockers and with Tom's rollers....
at 0.200 valve lift, figure about an extra 15 degrees of duration,
at 0.300 valve lift, maybe 20 degrees
at 0.400 valve lift, about 30 degrees extra duration over the stock rockers!
Numbers are approximate as my plotted graph is hand drawn and not computer generated. Wish I could calculate the 'area under the curve' but I need software to do that.

 

Good info!

I'll admit that my #'s off the top of my head were from 1.5 to 1.6...it's a bigger jump from 1.6 to 1.9, also depending on where the ratio's are in the lift curve.

Looks like a well designed product any way you look at it.

Hoping to see a plot of the g-force for 15 sec.'s next to the rpm plot for comparisons.

 

Walt, if you can post lift vs. duration figures for each case, I can plot them and integrate to compare the area under the curve figures.

 

8ad - I think this is what you were looking for. Tough to read the fine print, but the black and red lines are this year, green and blue are last year.. The G-Tech data is wonky, so you gotta take it for what it's worth. I did change shift points, and that shows here.. but I'd be hard pressed to say either RPM is entirely accurate, as it's reading it through a 50 year old cigarette lighter. But I do think it's relative within each session, and gives you an idea of what the engine is doing, within a couple hundred RPM either way (for instance, the 1600 rpm drop at the shift).

That said, I really wish the G's showed what you feel at the seat of your pants this year at the 6-7 second mark...it windmills at the 4900-5000 rpm point.

 

Thank you.
I have an older G-tech, I don't think it data logs. I use it to compare G's in one gear at a time. I've found that what it shows in max steady g's in first gear CAN equate to predictable 60' times. Even a .01 change can be seen at the strip, it CAN be very accurate for torque increases. Obvious common sense applied. Run your g-force with weight against the Wallace calc.for that. The mph even if not right, will show the change. You can standardize it accordingly.

I don't know if I'm using it right, but what I do is have it set to 0.00 while rolling steady, meaning a tad negative at rest. Suspension height changes with a run, so this is my way of standardizing. Wheelies might goof it... Remember, I'm not looking for a #, only repeatability. You might do differently.

The reason I took interest at this point is that some of the main parameters of your car very closely resembles one I did the top end on a few years ago. You may take influence by comparing these apples to those oranges...or not.

His (Her's really) went from 15.5 to 12.60 @4000lbs, using only 2 gears (similar to your powerband) with the same head flow (240 @max lift?). I normally compare mph's, but a pickup doesn't mph the same, and I've long forgotten. Her rt's were consistent enough to compare. Their project didn't start from the same point, so I'll give you what is relevant, hopefully useful to you...

I gave them more intake (dp 250cfm typical) flow not verified. A bit more cam (250*@.050 {with more rocker}), went up to 9.2-1, which flashed their converter higher (4000rpm), and the shift point increased, also longer collector and 3" duals, from 2.25".
To equate their shift point to yours looking at only cfm's based on displacement @100% VE, only to get a baseline...(I don't remember your displacement) If you are 425" 5850rpms, or 401" 6200rpms would be your new shift point based on the 250* cam, and same head flow. Also, you will make much more torque along the way.
The shift point supported by the intake, cam, exh., and stall would be the only major differences.

You went from 91.? to 103mph, that's a big jump. Your shift recovery is stronger on the graph. Hanging on longer should get you there.

You may not want that much cam, but every project I do has ported heads and I will state that when they are working right, more cam does not mean an automatic loss in bottom end. Quite the opposite is usually seen.

Looks to me like you're almost there...
Good thread.

 

8ad -

All total in this project I went from 89-90 mph (88 MPH on the AFB) to 94.5 - Like you describe, the G-Tech meter gets wonky and tends to overstate ET and MPH, but in the next run can understate them. That's why, like you, I tend to only use it to understand RPM and g-Force trends... a good example was when I did the transmission over and dialed in a bit of "Bang-Screech" to it, you can see what you feel in the seat of the pants on the attached g-force graph - the tranny hits harder and recovers better with the powerglide clutches..(black and red lines 2014, green and blue lines 2012 pre-tranny)I stick to timeslips for ET and MPH comparisons.



I am only now playing with pitch to see if I can normalize ET, MPH, HP and torque.... wish me luck. I had it at 2 degrees to account for the uphill grade of my secret test 1/4 mile, but now only use it at the track which is very flat.

That was an impressive improvement on the truck you describe, but unfortunately doesn't apply to what I'm trying to do..I'm trying to really optimize the stock configuration with with only bolt on parts. I'm shooting to race the PMSCDR series next year with my new motor, but they have very strict rules on cam, compression, head, intake etc.. deviation from stock. Trying not to cheat, at least not significantly.

So what I'm trying to figure out here is: If I (and by I, I mean Tommy) build the ultimate, optimized stocker within those rules (back to the AFB and everything, rules are here: http://www.purestockdrags.com/p/rules.html), what can I expect when I bolt on the Rockers, solids, Q-Jet and manifold, etc...in the "off season"? This year would indicate a improvement of better than .8 and 6.5 mph (I am going back to my AFB numbers here) on my old tired stocker. I'd like to see a full second and 10 mph between the two configurations, we'll get there..

I can run the Supercar Shootout or FAST series in "enhanced" form as long as it's stock appearing (Cast iron, Q-Jet, etc..) The idea is with very little effort and outlay I can bounce back and forth between stock and stock appearing. I do not want to go as far as swapping headers for manifolds or tearing into the long block twice a year.... My goal, however realistic, is to run mid 14s purely stock and mid 13s all dolled up with the 2 speed on a stock tire with no more than a 3.55 gear. That said, I wouldn't mind going full C/SA configuration with headers, slicks and 4.33's for a season, and comparing to the old Reynolds, Smyly, Long Beach times from back in the day. Mid 12's? Still sounds like fun, and I'd slap vinyl letters all over the thing and go match racing! If we build the new motor right, it can do all three configurations easy....

Hell, everybody has to have a goal, right?

 

Question,,,Why does the veh. weight show 3950# and 4000#??? should be one or the other.....:Brow::grin: