GREGGPENN

One of the things builders "soften" is what crawler performance is like with a bigger cam. Or...if you'll need to raise rpms to get it to idle as well. Along with this guy's longing for better 6th gear response, people should consider what "drivability" means for them....and if that's different for an automatic vs a stick?

I spent at least two years learning, buying parts, and waiting for the builder to bore/assemble the short block. During that time, the most I ever heard about "bigger cams" was how "driveable" they are. Yes, they idle (sometimes with the need for another 2, 3, 400 rpms. I've seen people posting that they NEED enough big cam gurgle to get a strong "bubba-la bubba-la" sound at idle. I question if they think about what "driveable" means? Just like the question of WHERE you want power, one man's "driveable" might not be so great to another.

You may be surprised how many tunes/hours I spent just trying to optimize starting, idling, and super-low-end performance of my MILD cam. Brian, one of the reasons for the suggestion of a smaller cam was this guy's OBSESSION/FOCUS on idle to 3k performance. In another thread, you should have read how he phrased the glorious shutdown of air to a TPI! LOL With his concern over lunging or running up RPMS too fast, I've seen no other poster so obsessed over low-end performance -- while almost shunning the need to "rip" the car at speed. It's led to feedback about diesel, electric, and really small cams. More importantly, it's led to knowledgeable people posting genuine solutions without understanding his truly skewed criteria -- compared to the norm.

Or...if the OP even has a probably functioning car.

drcook

these discussions have been started all over again over on thirdgen dot org. he didn't like what you all had to say about intakes, etc etc, so it has begun again over there.

bjankuski

Greg,
What you see on the dyno chart is not a 500 RPM bog or downshift it is the torque converter slipping from the torque of the engine up to the point where it finally builds up enough speed differential to hold the engine back. That point is approximately 500 RPM higher than the stall speed. That causes a false torque flash and is why I mentioned that you need ignore the peak torque flash reading since they are not real indicators of the torque the engine is putting out. You can always tell when this happens by the steadily dropping torque line on the dyno chart. It is a false reading in my opinion.

I have attached one last dyno sheet. It is the same 355 engine and superam combination installed in my 1988 Firebird (I have thousands of dyno sheets, call me goofy but that is what I like to do, make changes and test the results). In this test the car makes nearly identical power as when it was installed in the vette but there are some differences. The car is a T-56 6 speed with 3.45 rear gears and the exhaust is 1-5/8 shorty headers. I stated this pull at about 2100 RPM, so you can see what the torque and power are doing down at that low RPM. I do not have any of this combination with the TPI.




Phoenix I am more then willing to discuss all these dyno charts with you so if you are interested please contact me and we can discuss possible ideas.

One more note, if you are indeed shifting at 4500 RPM with the T-56 the next gear will pick up at 3100 RPM which is why I felt that my dyno charts starting at 3000 RPM were relevant to your goals.

GREGGPENN

Yup...he's back over there...starting over for the 15th time:

In case the link doesn't work, here's my favorite (BTW...He's already had several of us explain the TPI, base, upper long runners, superram runners, etc...

81c3

What a ......

Kevova

Remember he is researching something that MAY come about years in the future. His only consistent theme is he wants TPI. Theoretically he could install a 90-91 l98 engine with harness since ecm is designed to be engine compartment.

Tom400CFI

He doesn't want high RPM...but he'll pay for AS&M runners and base AND extrude hone "for that last bit of airflow before it starts to choke off" LOL, I say.



I think your right. Bragging rights; people only care about the peak numbers. Auto's make it hard to get a number from a low RPM.

Also; People forget/don't think about it. Some people think pulling from a low RPM is bad for the motor ("lugging") so they don't want to do it. Mostly, I think people are nervous on the dyno and just do what the dyno op tells them to do, and they end up w/results from ~3000 RPM on up.

Every time I go, I TELL the operator from the start, "I'm going to start my pull at 500 RPM...I want you to to start recording as low as possible". I get it up to 4th gear, then let everything slow down to below 1000 RPM. I mash it, and they always hit the "go button" a second after I hit the throttle so all my graphs have started around 1000-1200 RPM or so. Good enough I guess.

Tom400CFI

LOL. The results will be the same there too.

GREGGPENN

Plus, if you tune it yourself (like I did), it's really important to see what AFR and KS are doing -- even at low rpm/high load conditions. In reality, it wouldn't hurt to see what's going on in partial loads too...for tuning purposes.

Even though (at the time I dyno-tuned mine) I tried to dial-in "driveability" before putting it on the rollers, I didn't read long/hard enough to think of everything I might want to see. I didn't even know which came first between AFR and timing. (Plus, timing and AFR can fall hand-in-hand IIRC....meaning one being off can throw the other off too).

I think all of us who followed Phoenix from thread-to-thread noticed his propensity to object to EVERY answer. It may stem from the fact he's not (and can't be) serious about a purchase yet. It's all point/counterpoint in his mind -- with no real intent. He really does remind me of my "ex". I tried to carry on a debate with her for years...for lots of reasons. I got answer like "Oh you nerds are the only ones that see a need to figure everything out"....to tons of "Whataboutism". I always wondered why I spent so much time trying to "sort her out" then -- in her upper 50's wearing tight jeans -- I'd remember how few women dress/walk like that! LOL The problem is sometimes you just have to give up!!!! You know...cause of the drinking, ranting, shopping, HGTV-only-TV-viewing, impatience, self-centeredness, lack of mental focus, yada, yada, yada....

Sorry....I may have lost it there! Maybe I'm hoping this thread will be LOCKED! LOL

GREGGPENN

84 4+3

He wouldn't know 9 inches if it slapped... You know what never mind.

My cousin is on 3rd gen. He finds this hysterical.

64Scout

He's still going on about it? I made a few points about him in one of his other threads, but he never answered any.