May I put some perspective on my WHY? When the car was originally built I had the EFI remotely tuned by Richard Nedbal. The cam was mistakenly installed 8 degrees retarded. At that point in history, I took it to a dyno session. The results are on the sheets attached. Summary was max hp 402 at 5300 rpms, max torque 403.6 at 5120 rpms. I figured that that was low but the car needed tuning, etc. I have since had the EFI datalog looked at by AndyF and he liked the tune and he made some suggestions about the datalogs which were changes. So with all the parts and pieces I have in place, I have a 405 hp car. I simply think it can do better. The 1/4 mile calculators put it at 410 hp for a 3300 lb car at 11.7 sec. I have sorted the other parts for function, including degreeing the cam to grinder specs. So.... I need to make a change with the heart of the motor.
When good is not enough, Camshaft time again.
- Thread starter Kent mosby
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Kent, the only "WHY" you need is because it's your car. I agree though, it's got a lot more in it.
TT5.9mag
Two atmospheres are better than one
I’d be looking very closely at the converter and how much slip there is.
AndyF looked at the datalogs and assured me on multiple logs that it was stalling at 4500. If needed, I will change that as well. Thanks for the info.
TT5.9mag
Two atmospheres are better than one
It very well may be stalling 1500 rpm over what it’s rated. But I’d do some math and find out if it’s coupling or if you’re driving through it.
With 512 ci, you would think it could make over 1ft# of torque per ci without any effort, considering the HP 440 was almost making 500 ft#. If you look at Schneider's lobe list, their patterns include lobes with high dwell rates and moderate lift like Racer Browns:
| STX-20 302/267@.050/.540 with 1.5 RR |
The Nose of the STX-20 Solid flat tappet is very broad...
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I have a Hughes solid flat 264-268 with a little more than .660 lift and the springs and retainers , edm lifters just sitting around.
It was a little small for my race only 470 but it made plenty of power. 600 ft lbs at 3k
PRH
Well-Known Member
10.5 512 with TF 240’s and what is essentially the equivalent of the Comp XS282S cam should easily make around 600ft/lbs tq……..but the duration is a little short for that combo to make a big hp number……..so I’d except the hp to be somewhat lower than the tq.
Adding duration won’t change the amount of peak tq much, but should allow the top half of the tq curve to fall off slower, which makes the math more favorable for a bigger HP number.
The trade off is……. More duration usually comes with reduced street friendly manners.
The basic engine combo would tolerate quite a jump in duration(like 20deg)………. But it would come with a noticeable drop in driveability.
Adding duration won’t change the amount of peak tq much, but should allow the top half of the tq curve to fall off slower, which makes the math more favorable for a bigger HP number.
The trade off is……. More duration usually comes with reduced street friendly manners.
The basic engine combo would tolerate quite a jump in duration(like 20deg)………. But it would come with a noticeable drop in driveability.
mygasser
Well-Known Member
Tunnel ram
Not sure what you mean.
TT5.9mag
Two atmospheres are better than one
With big hp/TQ an engine can basically run through the converter and it will continuously slip more than it should. There will always be a little bit of slip (unless you have a lock up) but a good quality converter will couple and accelerate the car. There’s a bit of math to determine how much the converter is slipping using gear, rpm, mph stuff and I’m suggesting you look in to it.
PRH
Well-Known Member
I don’t approach it that way.
I prefer to define the operating parameters and power/performance goals, then try to come up with what I feel is the best way to get there.
So, there is no one “best”.
With street cars it usually comes down to which things one places the most priority on, and which things are more “compromisable”.
Race cars are generally much easier overall, where the compromises are usually based around cost and maintenance.
TT5.9mag
Two atmospheres are better than one
Hard to argue with good logic.
I'm confused. I think you said it made these dyno numbers with the cam errantly retarded 8 deg. Then you later say you have since corrected the cam centerline and degreed it to the cam mfg spec. Is that correct?
Has the car been to the track with the cam now properly degreed (if it was)? If so, what did it run?
A 512 RB in a Scamp? That's a rocket waiting to go! Seems like that's an easy 10 sec street/strip car that I would froth at the mouth for!! Sadly, when I was in Michigan a friend i met at the track had a 505 inch BBM in a later model Dart. It woukd only run about 7.30's in the 1/8 mile. Never made sense to me and I moved before he figured it out (if he did). And there's a guy here in Florida with a 440 in one that also runs about 7.30. Car is quite a bit lightened too. Makes no sense to me as I love me a BBM even though I run a 408 that's faster.
Having run a 246/252 Schneider solid on 110 lsa with .550 lift and 240 CFM heads, I’m stumped by the OP’s cam choice.The 360 ci with 10.6:1 that failed to pull past 5600 in 6500’ da. I can’t grasp the OP’s camshaft being large enough, unless he wants low and midrange only.
My understand is “dwell” fills the cylinders of large stroke engines.
As for the converter, I’d go with a 4700 9.5” dynamic. Mine drives the pits a 2500 And loads the trailer well.
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PRH
Well-Known Member
Could you clarify the part about won’t go past 5600?
Is it that it peaked at 5600 and then the power started falling off after that?
Or the motor protested strongly when trying to exceed 5600?
yes , after correcting the degreeing of the cam, Our best was 11.46 on a semi prepped track 118 mph. Consistent 11.7-11.9 at 117 on no prep track. Prior to correcting the degree of the cam, best was 12.2 116 or so
TT5.9mag
Two atmospheres are better than one
In 6500 ft of DA everything quits pulling.
The trickflow 240 heads flow more than 240cfm.
TT5.9mag
Two atmospheres are better than one
PRH
Well-Known Member
Interesting.
All I can tell you is that sometimes what I you feel in the drivers seat often doesn’t accurately represent what the power curve would look like on the dyno.
That’s fairly close to what we would run for a cam in the circle track stuff I was involved with years ago, and they would turn those close to 7k.
BSB67
Well-Known Member
I think a good street-lobe solid roller could add a bunch of power. I don’t think he needs 20 more degrees to get there if everything else is right. That said, It’s not clear to me what the OPs budget is and if converting to a roller is in it.
Also, like someone else said, even with another 50 hp, he’s s still at 11.0s at 122-123 mph.
Seems like maybe it’s more than the cam holding it back, like others mentioned too. Converter, fuel, collapsed muffler….
It might be helpful if the OP posted some time slips and corresponding DAs for the runs for folks to look and to see if it makes sense or something pops-out.
Also, like someone else said, even with another 50 hp, he’s s still at 11.0s at 122-123 mph.
Seems like maybe it’s more than the cam holding it back, like others mentioned too. Converter, fuel, collapsed muffler….
It might be helpful if the OP posted some time slips and corresponding DAs for the runs for folks to look and to see if it makes sense or something pops-out.
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