Must be nice. Since I learned to drive a manual in my late teens, I've driven one automatic that didn't suck. It was in a Mitsubishi Mirage (of all things) and managed to learn my driving style on the drive from LAX to Port Hueneme. I had that car as a rental for two weeks and actually kind of liked it. However, if for some odd reason I was going to buy one, I'd still get it with the 5 speed.

I've never driven a manual transmission vehicle and wished it was automatic. Ever. I couldn't count the number of times the reverse has been true. A manual transmission has a perfect shift strategy. It goes in whatever gear I put it in, when I decide to put it there, and then stays in that gear until I take it out. I converted my Mercedes (Germany's idea of a taxi cab) from auto to manual about ten years ago and it improved the car greatly.

 

Sorry, but I can't let this pass! I should, but I can't.

Your numbers are way outta whack. You're ignoring (or simply not aware of) the various build configurations of various USA V8 engines.

But, still, the Gross-versus-net differences are not are dramatic as you assert, at least not always

Simultaneous to the switch from gross to net power ratings the engines were being detuned.....and some of the high horsepower versions eliminated entirely so a before/after comparison isn't even available.

True, Chevrolet made jillions of the bog standard 160hp (SAE net) 350 V8s and even installed them in a lot of Corvettes. That specific configuration/state of tune didn't exist when the gross system was in use, but, if it did, it would have never been rated at 350hp (SAE gross). It would've been rated at something like 250hp (SAE gross)

A good example of the period (1970-72) would have been the Chevy LT1 350. At peak 1970 configuration it was rated at 370hp (SAE gross). With the 1971 compression drop/detune it was re-rated at 330hp (SAE gross) and 270hp(SAE net). Not 160hp (SAE net).

If you want to be dramatic you could say that Ford's 351 was 330hp (SAE gross) but only 162hp (SAE net). But that would be grossly inaccurate. The 330hp (SAE gross) version was rated at 285hp (SAE net). The plain-jane 351s, however, were indeed rated at 162hp (SAE net). These were the bog-standard versions that, a year before, were rated at 250hp (SAE gross)

What you're doing, intentionally or not, is taking the highest possible examples (high performance build configurations rated under the old 'gross' system) and comparing them to the lowest possible examples (plain vanilla build configurations rated under the new 'net' system).

It's apples and oranges.

Cheers
DD

 

Not that I want to go too far into the weeds, but......

A) Lots of different build configurations. An XJS 6 cylinder coupe with manual trans had a curb weight of something like 3750 pounds. At the other extreme, a V12 convertible with automatic trans was something like 4400 pounds curb weight

B) Confusion over, or disregard of, gross vehicle weight versus curb weight. Part of this come form the door tags ....which show GVWR-gross vehicle weight rating. This is the is the all-up maximum weight. Full passenger and luggage capacity + full tank. Curb weight is minus the passengers and luggage.

Cheers
DD

 

MG , after reading many your postings here , can i ask (are you in convelesing home, or encarserated , rehab maybe?).
something just does not make sense!
like you say you race cars(XJS), why NO pix of you with a race car?
not one from yester-year!

 

Same here, and on top of that 16MPG city fuel consumption for v12 mid 80's car is not that bad i think. I had converted my xjs to manual BMW 5 speed soon after purchase of the car in 2002, after conversion it was able to pass 250km/h point easily, now have upgraded to 6spd from E39 M5, 1 spd is 4.227 perfect for city slow traffic even with 2.88 final drive.

 

Your comments are correct but how many people who put Chevy V8’s in their Jaguars wound up with LT1’s ? Compared to how many wound up with 160hp versions or worse the 305 which looks to be the same once cleaned up and painted? For a few hundred dollars the shop Would buy a chrome kit that replaced the valve covers and air cleaner Plus a few other things so the owners saw a little bling where before they only saw hoses and a mess.
plus most V8’s were also using the GM 350 transmission instead of the turbo’d 400.

I used to pick up good V12’s from a local shop that specialized in the swap. The shop didn’t know which were HE’s and which were Pre. HE’s and it was a Jaguar shop.
I’d do a leak down test and a backwards oil pressure. ( I had an air chuck I’d hook up with a pressure gauge and if it would swing up before all the oil blew out, that told me there wasn’t anything mechanically wrong.
Jaguar V12 came in and didn’t run it almost always left with a Chevy. ( that they would get from a wrecked car). pressure wash, add the Chrome. Replace the carb with a rebuilt one and put in new plugs and wires. If it came in with a 2 barrel they’d pull that off and buy an aftermarket 4 barrel aluminum one. The owner never knew the truth.
They would tell the owner that a rebuild would cost +$10,000 and they could get a new fresh from the factory crate engine with 350 horsepower. For only $5500.

 

The pictures I’ve posted have all been taken by other people. I’m not a big picture collector/ taker. Too busy working etc. If you take a picture of me my hands are greasy, probably smudges on my face and I’m rushing to get ready for the next session.
Im old, I’m fat, and do it all myself.
No I haven’t raced in the past few years. But I’ve told you how to check me out. I can still dig out pictures of the Black Jack special and the XKE v12 roadster on the Internet.f
If you’d like to watch me race one of my Jaguars.
type in 1986 Bahama Vintage Grand Prix.
You’ll need to watch carefully this was put together by Steve Kline. Driver of the 1958 Echidna ( they called it a 1957 Corvette.).
Since we both live in the same metro area. And I’ve known Steve Kline for a very long time there are a few background shots of me driving my Black Jack Spl and the Car I served as the crew chief on the 1959 DeMar ( who paid my entry and expenses ).

 

Dave 216,, i drove manual hand shifted cars since i could drive 1949, , now on my 78XJS V12 , i use a GM 700R4 trans and a 3.73 rear drive LSD!
i will be impressed ONLY if you can shift gears from 1st to 2nd at full throttle( NO lift) at 6000revs, then from 2nd to 3rd,same no lift 6000revs, and 3rd to 4th same way!
we could race if we were closer, but it goes like this(and i have done many times),!
we start from rest , and go and when i shift from 1 to 2 gear , my car will pull ahead of you by at least 10FT(3meters), because i shift at FULL throttle, and 2 to 3 gear etc.
you have to make up that loss of space that i get at each shift, your shifting while i'm pulling ahead, by the time i'm at 120mph, you will be behind quite a bit!
simply because you are taking a time frame to let off throttle ,disengage clutch, shift the lever , let the clutch out , and jump on the gas pedal again!
and if you have NEVER driven a newer car with the 8/10 speed auto matic you are missing an experience of driving!
ron

NOW when some one finally gets a Dual clutch trans in there cars, things will change,, Maybe?

 

You haven’t shifted a dog ring transmission have you? Unless you have driven real race cars you haven’t. Dog ring transmissions require full throttle shifts without use of the clutch. In fact The only time the clutch is used is to get the car rolling. From there on, the faster you move the lever the better for the transmission.

 

The T56 magnum I have behind a 6.0 Jag v12 in an XJS coupe can be shifted quickly with out the use of the clutch. All I do is slightly back off the throttle and click it into the next gear. You have to be quick. In racing application of the T56 mangnum they put an ignition cut out switch on the shifter so it can be shifted in one motion with minimal loss of torque. This is why light weight flywheels are used in racing...so the RPMs drop just enough for a quick shift. The car already has the alu flywheel and I'm toying with the idea of an Ignition cut on the shifter.

You have to be very quick when doing it with the the T56 magnum...just like a dog box. The two older t56's I have in a Holden GTO and another from a 1993 LT1 can not do this. I tryed. All shorts of bad noises followed.

 

If you know what IS correct then why post information that is incorrect?

Probably none.

All I'm driving at is this: If you're gonna use horsepower numbers to support your position, use the right numbers!

Cheers
DD

 

let’s see you are saying that older engines which were gross horsepower ratings should be compared with DIN Net numbers?
or are you saying I should allow Gross or advertised horsepower numbers to compete with DIN net numbers?
maybe you are saying that the number of 1.0139 isn’t the correction for DIN to SAE?
Maybe you’re saying that since some old Chevy V8’s Advertised 350 or 450 horsepower back in the early 70’s that only those engines wound up in Jaguars?
please clarify.

 

The T56 uses syncro’s. A true dog Ring you do not lift the throttle. Not a bit. In fact on the down shift you have to floor the throttle.
just to be clear,
down shifting is done with the throttle off to use engine compression under braking
mat the moment of a down shift you floor the throttle that releases the dog and matches gear speed with the next lower gear.

throttle off - car slows,
floor the throttle - jam the lever to next gear
throttle off - car slows etc.
absolutely required heal and toe technique Actually I roll my ankle over to the throttle while holding down the brake.
no cluctch ever touched.
new versions don’t have a gate but rather a lever to move forward for up shifting and backwards for down shifting.

 

I'm not saying any of those things.

What I am saying is illustrated by the examples I used.

I quoted an example of type of numbers and comparisons you were using that were incorrect. And I gave examples of correct numbers and comparisons, which you agreed were correct.


Cheers
DD

 

You simply have been mislead. The Chevy’s of old with 350 horsepower 350’s and 450 horsepower 454’s were advertised horsepower Or gross horsepower.
After 1973 the power ratings changed from advertised to SAE net rating.
suddenly Chet 350’s had 160 SAENet horsepower and 454’s had 235 horsepower.
while Jaguar in 1973 was at 242 DIN net horsepower. The difference between SAE rating and DIN is nearly identical. To get the same rating multiply DIN x 1.0139 so
Chevy =160 hp
Jaguar= 245 hp.
A Few years later in 1975.
Chevy = 160
Jaguar= 267
later Chevy went to 190
Jaguar went to 319
eventually they both stopped production.
Jaguar of the V12
Chevy of the 350
Chevy made the LS
Jaguar made their V8 with up to 510. Hp.

 

Right numbers ?
you mean the advertised numbers are right because you want to believe them? Or because you read them someplace?
while SAE net numbers ( or DIN net times 1.0139 ) aren’t right?

 

what I agreed is that Chevy lied about their horsepower pre SAE Net rating And the exceptions you pointed out About post SAE net ratings were probably correct
I didn’t use European spec numbers which were notably higher. In an attempt at brevity.

The simple fact is people who swapped 350’s instead of V12’s got less not more power.

 

This is mis-information some people may even call it fake news. It's pervasive apparently. Racing Transmissions with Dog style engagement rings need to be double de-clutched or rev-matched for downshifting. Up-shifts are accomplished with a throttle lift or brief ignition cut. Sometimes the rev limiter can do the ignition cut for you. You bounce the engine off the limiter and shift. Great skill is required. Downshifts have to be rev matched, just keeping your foot in it will break the gear box quickly. Both up and down shifts can be done with out the clutch but downshifting this way requires far greater skill with rev-matching or the "gearbox problems" will occur. Manufactures like Porsche used to make gear ratios with easier mathematical factors of RPM and road speed to help with quick mental calculations. It's all moot at this point for factory race cars, and high budget racing series. Not to mention the increasing popularity of E-racing and I-racing. Most of these car are so fast and way past the capability of humans to shift them quick enough. The driver's mental bandwidth can focus on the track not rev-matching which if done poorly will break a gear box quickly. This is what I know from driving an old Porsche with a dog style trans with helical gears. Transmission rebuilds were somewhat frequent and after a while the teeth would round over and could no longer be shifted quickly.

This is why the T56 Magnum is so popular with hobby racers and fast road cars becasue it can be quickly upshifted with out the clutch and can be downshifted very quick even with an in-exact rev match. You give it your best and the syncros do the rest.

Modern PDK's can do "no lift shifts" but still use computer based torque management during shifts. They accomplish this shift up, or down down have the next gear already engaged with a 2nd clutch. Then the gear switch occurs by the clutch. At this point I'm not a fan of PDK's You dont get the full envolment I'm used to. One of my younger friends has PDK in a Porsche and the clutch is a relic to him. The paddels used in a PDK are analogous to the video game driving experience so it's no wonder why adoption has been fast and abrupt. There are very few die hards that still want three pedals. So few, in fact, that GM doesn't offer a clutched manual on the C8 Corvette. There was a quick and initial outcry over this decision but it died down quickly. GM is clearly trying to attract younger buyers.

 

Doug dont waste your time with MGs BS , he is just trying to suck energy from you!
me and him had many wastes of post on JL forums yrs back!
he is argumentative at best!

 

YES icsa, is more correct than most others said on this thread!
including me!