At Allison we replaced literally hundreds of mechanical combinations of parts with single digit assemblies and manage applications via ECU software calibrations and adaptive control. It makes manufacturing, production control, inventory, and service support so much easier, not to mention a more consistent and durable product.
Cant we invent carburetors that atomize fuel as good as fuel injectors by now?
- Thread starter The motor guy
- Start date
Transmissions are far less complicated because electronic control, In fact 4 speeds (3 speed with O/D) would still be in use if it wasn't for electronics.
All 6, 8, & 10 speeds are Clutch to Clutch units requiring precise apply & release of clutch packs.
A TH400 for example is far simpler......Forward Clutch on, 1st gear. Intermediate Clutch on, 2nd gear. Direct Clutch on, 3rd gear. In 3rd ALL 3 clutches are applied, No clutch had to come off.
While some mechanical units used a Clutch to Clutch shift, Ford C6, Chrysler A727, 700R4, 4L60E are all Clutch to Clutch for the 2-3 upshift and what they all share in common is a Intermediate/2nd Band.....3rd clutch oil pushes the band off as the Direct/3rd Clutch comes on.
In other words.....This only works on a Brake Band.
TH400/TH350 employ a Intermediate Sprag/Roller Clutch that allows the Direct Drum to overrun without releasing the Intermediate Clutch.
Using a unit I'm very familiar with.....The GM 6LxxE, All the valves & spring weights are the same in the Valve Body, The Calibration in the TCM is what's different between a 6L90E in a 3500 pick-up & a 6L45E in a Cadillac ATS.
While there are differences in the Upper Valve Body Casting (Where the 2-6 & Lo/Reverse feed holes are) But that's because the 6L90 has longer drums to hold more frictions & the Gearset is bigger pushing everything rearward.
I've used a '15 ATS 6L45E lower valve body & TCM (TEHCM) in a '15 2500 6L90E with nothing but reprogramming the module.
Take a 700R4.....There are literally 100's upon 100's of different Valve Body & Governor combinations......No living soul knows exactly what is what either. They are a tuning nightmare.
Worth noting.....Bands/Servos & Accumulators are pretty much extinct in transmission design, Electronics made that possible.
Does direct injection cure the lumpy cam problem?
Yup. The 1" incher was for guys with a fairly or stock hood height.
Intake setups are complicated, size them right and extra length runner can really sing.
Too big a cam, carbs, or runners and they go right to dogs only running up top and not well even then.
Or they idle at 1500 RPM
Half the guys with the big tunnel rams were total posers who weren't outrunning guys with single 4 barrels.
800-1K big blocks on a single 4 barrels are common.
I've never seen a direct injected mill that was cammed to the hilt.
In any case it wouldn't solve the lump, per se, but it might let it idle at a reasonable speed.
I suppose that everyone has a different opinion of what constitutes “cammed to the hilt”.
I postulate that direct injection engines are not negatively affected by valve overlap.
The new 6.6L 553 hp LT crate engine would be fun to monkey with, starting with 282/[email protected]” on 114 LSA, keeping in mind the stock 1.8 rockers.
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For sure on opinions about cammed to the hilt. My definition of that is going to be different from another guys.
The last 20 years I've been building I/O boat engines which have really strict behavior limitations. >=900 RPM idle.
110 LSA max, 6000 RPM cap.
On a manual trans car, the sky's the limit.
I dont know that crate package - curious - does that mill need the 282/298 .05 to make 553?
- or is that what you'd want to put into that mill and see where it goes?
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B is correct. Stick the 282/298 .050” @ 114, ICL in at 113 and see what the engine is capable of in stock form with appropriate valve springs of course and enough intake CFM to avoid restricting the horsepower.
This would test the limits of the heads, but more importantly what would the low rpm characteristics be with direct injection versus port injection or carbureted? Valve timing: intake 28/74 exhaust 84/34 @.050. Lobe lift would be over .400 and I have a hankering the engine would like a 1.9 intake rocker ratio.
On your I/O boat engines, was max LSA of 110 derived from trial and error and applicable to all engines?
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Isnt that crate design inherently port injected? How would one retrofit a DI system and then what would power the high pressure pump?
It's always fun to put something on a dyno and keep camming it up till it stops climbing to see where eth heads stop - or it just stops running. Ive gotten 2-3 cam changes a day with guys like Steve Brûlée helping out.
The wider you make the LSA the more likely the engine is to revert water back into the engine.
Especially in a manifold vs header style exhaust.
Like anything there is a range of what you can get away with and you need a wet dyno to really get it right.
Jet boats, Big high PER v drives, can run dry headers, I/O use a completely water jacketed exhaust often under water.
Too much cam or not enough motor?
GM part number 19436191 6.6L 523 hp.
Valves 2.13x1.59
Cam 218/[email protected] LSA 121 lobe lift .305”
1.8 rocker ratio = .549” valve lift
.050” valve timing @ 117 IcL: -8/46 60/-9
Compression ratio is only 10.8:1
DI 150 bar
$8948.80 USD
You’re right Jeff, 282/298 @ .050 is too much cam for not enough compression ratio, unless of course you’re adding a few hundred horse nitrous to the equation.
SammyChevelleTypeS3
$50 site donor 2023
Right. There is a TRUTH though. Fuel injected engine technology has been possible since at least the 1930s. Mechanical FI came in some early 1950s Chevrolet Biscaynes (drag racers used some) and was also an option in some Corvettes only to be done away with by two (poor) excuses..... #1 they said most consumers were scared of it , feeling it unsafe not knowing enough about it. (LoL) What a croc?
#2 Automakers made the excuse that it was too costly to train the mechanics..... Hmmmmm? Anyone who has worked on carbs probably will say they would rather work on FI than all the pieces it takes to overhaul any standard 60s thru 90s carb. Oh well. We certainly benefit from FI these days.
FYI the mechanical FI used on C1 and C2 Corvettes was very finicky, at best. Many frustrated owners removed the unit and replaced it with carbs. Here's my BIL's 62 Fuelie. He is becoming pretty knowledgeable and has several complete units.
JHZR2
Staff member
If only the oil companies hadn’t destroyed the 100 mpg carburetor…
4WD
$50 site donor 2025
And joined the cartel against intake tornados
SammyChevelleTypeS3
$50 site donor 2023
Love that model. Like the paint job as well.
I liked that old Rochester FI unit, played with them alot in the old days.
You'd think the pandemic and chip shortage would have been the wake up call to anything that has an electronic chip. Just wait till the day comes and they all get fried by EMP. Then ya lll will hate EFI. Cause there is no way to fix a small black box full of surface mount components and secret IC's when they are unobtainium. Its just not like the good old transistors and vacuum tubes.
You'd think the pandemic and chip shortage would have been the wake up call to anything that has an electronic chip. Just wait till the day comes and they all get fried by EMP. Then ya lll will hate EFI. Cause there is no way to fix a small black box full of surface mount components and secret IC's when they are unobtainium. Its just not like the good old transistors and vacuum tubes.
My BIL Mark got it as a basket case. He tells me he hates painters. Ha!Love that model. Like the paint job as well.
His 62 Fuelie wins every show it's in. He takes it to retirement homes cuz many old timers get a kick outta it
He's also got my 68 L36 Roadster
You are assuming that we want uniformed atomization of fuel all the time. Today's engine want certain area more lean and rich than the other for better efficiency, emission, and power.
