Tiff Needell's 1980 Rover V8 S SD1 Group 2 on our rollers

Tiff Needell's 1980 Rover V8 S SD1 Group 2 on our rollers

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Mignon

1,018 posts

88 months

Thursday 23rd February 2017
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dom9 said:
Think you forgot a link there, Miggy!

It seems that everyone involved with this car/ engine believes it to be a 3.5 litre so we kind of have to take their word for it and fill in the gaps.
Sorry, link fixed.

If it's really a 3.5 then the power and torque figures are way overstated. That would then put things back in the same situation as the Crossflow power graph which was also way higher than anyone else has ever managed. Maybe the claimed 377 engine dyno bhp was a red herring, it never really went on an engine dyno and frankly if it had done I'm now wondering why it would need to go to rollers to be set up. Simplest answer is these rollers just over read a lot.

People have been churning out nonsense information in the tuning world since the industry started but the numbers never survive an accurate independent engine dyno test. I'll stick with what I know real engines actually produce.

Mignon

1,018 posts

88 months

Thursday 23rd February 2017
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PeterBurgess said:
Do you remember this topic I posted Dave?
http://www.pistonheads.com/gassing/topic.asp?t=149...
Right, I've just had a look. Full race Rover V8 engine built by John Eales again and this time with their own engine dyno graph shown. You say in that thread the engine has 30 ci cylinders. That's 240 ci total or 3.9 litres. Engine dyno torque 300 ft lbs. 77 ft lbs per litre. Just what I've been telling everyone is possible. I rest my case. You keep digging if you like though.


Edited by Mignon on Thursday 23 February 18:29

227bhp

10,203 posts

127 months

Thursday 23rd February 2017
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Mignon said:
dom9 said:
Peter - what fuel was this engine running?

I am finding a figure of 550 lb/ft on a 358 ci NASCAR engine (5.86657 litres).
Here is an actual late spec Toyota Nascar 358 ci engine being dynoed in November 2013 presumably for the 2014 season. The dyno is in the Evernham Motorsports workshop which is now part of the Richard Petty operation.

https://www.youtube.com/watch?v=EScO0-NHGs0

The rpm and SAE ft lb torque dials can be read clearly when the camera is in the right place. The engine is being revved to over 9500, peak power at 770 bhp is over 130 bhp per litre and the torque just nudges 500 ft lbs on a couple of runs and maybe 505 on one of them so 85 to 86 ft lbs per litre.

So clearly given their 5 million dollar engine budget per season and that every part of that thing is custom designed and CNC machined they're doing something drastically wrong when they can't even get close to an old Rover V8 but someone else can phone them and tell them how crap they are.
Edited by Mignon on Thursday 23 February 08:46
That Nascar engine is on 98 MON which is at the most 95 RON, that (along with 'accompanying mods') could explain it?

Edit - Sorry, assumed the Meercans had quoted a MON rating as per usual when they hadn't!


Edited by 227bhp on Thursday 23 February 16:13

dom9

8,040 posts

208 months

Thursday 23rd February 2017
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GreenV8S

30,149 posts

283 months

Thursday 23rd February 2017
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dom9 said:
I'll be honest; I am still very skeptical as I have never really seen any evidence of such high torque per litre figures from that type of engine.
Does the smaller capacity make it easier to achieve big power per liter or torque per liter? I would have guessed it does.

dom9

8,040 posts

208 months

Thursday 23rd February 2017
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GreenV8S said:
Does the smaller capacity make it easier to achieve big power per liter or torque per liter? I would have guessed it does.
What's your thinking? Smaller pistons/ stroke giving less friction? Slight thermal benefits to cylinder size?

I'd guess that could be true but was probably more 'in the noise'/ marginal gains.

Having said that, sure; who knows what's inside (i.e. piston rings, bearings etc).

GreenV8S

30,149 posts

283 months

Thursday 23rd February 2017
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dom9 said:
What's your thinking? Smaller pistons/ stroke giving less friction? Slight thermal benefits to cylinder size?
I was thinking more along the lines of the manifold and valve sizing being ultimately constrained by the bore geometry, while the amount of air you need to get through them (for a given volumetric efficiency) increases with capacity. I mean, if you stroked that 3.5L engine down to 1L then it ought to make a really *really* well flowing 1L that could produce impressive power-per-liter and torque-per-liter figures, even though the absolute figures would be pretty feeble compared to the 3.5.

Mignon

1,018 posts

88 months

Thursday 23rd February 2017
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dom9 said:
You should also note that this fuel is highly oxygenated. 5.6% by weight on the spec sheet. Getting power and torque is all about getting oxygen into the engine via port air flow so if you can just squirt some of that in with the fuel in liquid form you get a big advantage. When you factor in that plus the very high octane value of this fuel you have a few percent advantage on potential torque per litre over what a pump fuel UK engine might produce on the same CR. That brings you down from the 85/86 ft lbs per litre the Nascar engine showed to very low 80s just like you'd squeeze out of UK pump fuel with the same sort of effort. All these little factors help correlate why peak torque per litre (or BMEP) is so invariant over such a wide range of engine specs and so invaluable in helping determine whether power figures are BS or not.

This thread has sadly gone the same way as every other one Peter starts but hopefully it has taught other people some facts of tuning life. You can't just pluck BS torque figures out of thin air like 110 ft lbs per litre for a 2 valve (or any number of valves!!) to try and justify why an old nail like a Rover V8 shows 94 ft lbs or 100 ft lbs or whatever on your particular rollers when that's physically impossible. Saying things like "just because you've never seen it doesn't mean it isn't possible" is a feeble excuse for not knowing what's possible or not. I've never seen a unicorn but I'm damn sure there aren't any. (Unless they live in the calibration control box in Peter's rollers)

We've now seen that John Eales are showing the exact same torque per litre as I stated was reasonable in the first place for one of their own race engines on their own engine dyno - 77 ft lbs per litre. The numbers only go crazy when engines get run up on Peter's magic rollers, just like in the Ford Crossflow thread.

Also never forget that American power figures have that 4% BS correction factor built in over and above the actual numbers the dyno reads before you start quoting them to try and justify anything. The numbers in that Nascar clip were straight off the dial with a dyno cell air temp of about 60F. You aren't going to ever see real numbers higher than that and I doubt most Nascar races are run in temps that cold but you can still see the "corrected" figures on the screen that are higher still and which give the headline numbers like 540 or 550 ft lbs which get bandied about for those engines. Take that 4% out and you're down into the 520s tops. Same applies to the Engine Masters stuff which aren't even comparable because they're tuned for torque not power and on ridiculous CRs and only have to last for a few minutes before they det to death. Factor all those things out and they're back into the low/mid 80s ft lbs per litre as well.

You can't change the laws of physics. All you can do is ignore them or fail to understand them. 2v road car derived engines on pump fuel struggle to break 80 ft lbs per litre. 4v ones struggle to break 90-93. Money no object designed from scratch gets you a little more. Mid/high 80s for 2v, 96/97 for the old normally aspirated F1 engines.

Those numbers are never going to change. Whether people still choose to ignore them is beyond my control.

Mignon

1,018 posts

88 months

Thursday 23rd February 2017
quotequote all
GreenV8S said:
I was thinking more along the lines of the manifold and valve sizing being ultimately constrained by the bore geometry, while the amount of air you need to get through them (for a given volumetric efficiency) increases with capacity. I mean, if you stroked that 3.5L engine down to 1L then it ought to make a really *really* well flowing 1L that could produce impressive power-per-liter and torque-per-liter figures, even though the absolute figures would be pretty feeble compared to the 3.5.
No. There's almost nothing you can do (a couple of percent here and there) to make a particular design of engine make more torque per litre just by changing its size. When the cylinders are full they're full!

PeterBurgess

Original Poster:

775 posts

145 months

Thursday 23rd February 2017
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For instance the MAE 998 engine? Our guesstimates of one of the two we dyno was 80 lbs/ft per litre and 124 bhp/litre at the engine wheel peak torque 68 ish and max wheel bhp 100 at 7400 and 8250 respectively. Remember this is breathing through a single choke Weber (half a downdraft) and a restrictor, amazing really. It is music to the ears at 10000 rpm....1965 engine too!
Peter

GreenV8S

30,149 posts

283 months

Thursday 23rd February 2017
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Mignon said:
When the cylinders are full they're full!
Mignon said:
2v road car derived engines on pump fuel struggle to break 80 ft lbs per litre. 4v ones struggle to break 90-93
Why does the number of valves make a difference, if you're expecting to get the cylinders 'full' in both cases?

Mignon

1,018 posts

88 months

Thursday 23rd February 2017
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GreenV8S said:
Why does the number of valves make a difference, if you're expecting to get the cylinders 'full' in both cases?
Well the very obvious deduction, albeit not being an answer, is that "full" for a 2v engine is not the same as "full" for a 4v one. However it's much more complicated than that and is not all about cylinder filling anyway. To answer it fully would take quite a long technical article. Even if I were minded to spend the time writing one why would anyone in here believe it anyway? One thing that has become clear from this thread is that people know so little about the topic of torque per litre that even the most outrageous BS doesn't get anyone to do more than say they might be a bit dubious because they simply don't know the answers.

GreenV8S

30,149 posts

283 months

Friday 24th February 2017
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Mignon said:
Well the very obvious deduction, albeit not being an answer, is that "full" for a 2v engine is not the same as "full" for a 4v one.
The deduction that seems most obvious to me is that when you say 'full' you don't actually mean as full as it could ever possibly be - only that it has reached what the designer considers the optimum for that particular engine design. Remember that I'm not asking whether a smaller capacity could produce more power or torque, but whether it could produce more power or torque per liter.

PeterBurgess

Original Poster:

775 posts

145 months

Friday 24th February 2017
quotequote all
Do you reckon Burt Munro accepted 'learned' maxima? Ooooh you can't get more than this or that? Race and record losers in the making smile

The bhp/litre measured at the flywheel or wherever can be improved with reducing friction and even more so by using fuel such as nitromethane so, to define limits and expectations, we have to look at the system boundaries and see if we can improve or push the boundaries. This is what I have done for 30+ years and continue to do so.

Take out the second compression rings and on bike engines we have seen improvement in bhp/litre, not due to better porting, cams, intake or exhaust, down to less friction.

At present we work with a guy who has pushed forwards TR4 bhp by hard work and maybe £150,000 research, people all round the world are involved and teamworking. It is paying off and the maximum bhp for a 2v race engine has been passed a couple of years back. Not on my wonky rollers either smile



Peter

Sardonicus

18,928 posts

220 months

Friday 24th February 2017
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Well after just seeing this lot and reading opinions of posters more knowledgeable than myself and yes I am a RV8 fan-boy that BHP figure at those lowly revs for that displacement scratchchin Nah I'm not convinced whistle

Mignon

1,018 posts

88 months

Friday 24th February 2017
quotequote all
GreenV8S said:
The deduction that seems most obvious to me is that when you say 'full' you don't actually mean as full as it could ever possibly be - only that it has reached what the designer considers the optimum for that particular engine design. Remember that I'm not asking whether a smaller capacity could produce more power or torque, but whether it could produce more power or torque per liter.
Perhaps Peter would like to answer your question. He's a "tuning junky" after all.

dom9

8,040 posts

208 months

Friday 24th February 2017
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Mignon said:
...Whether people still choose to ignore them is beyond my control.
To be fair, I think it's fairly clear that many on this thread don't believe the figures nor have taken them at face value...

However, there seem to be a few possible options that might explain what is clearly an 'unusual' result:

1. The rollers/ operator/ software are wrong
2. The fuel tank is full of rocket fuel
3. Some kind of exotic internals/ heads/ undisclosed capacity

I don't think we're ever going to find out which it is as Peter didn't fuel up or build the engine (by the sounds of things).

I am sticking to my belief that you can't make this power/ torque (per litre) from an RV8 on V-Power (other brands are available) and JE would seem to confirm that as would the learnings of the great and sadly departed (from this forum) Dave Baker of Puma Racing fame wink

But since there remain some unknowns and I can't confirm which of '1', '2' or '3' (other options may be available) it is - we do kind of have to take it at face value, despite the fact that '2' is unlikely and no one will admit to '3' (probably).

There's some good info on this thread though and although it perhaps hasn't gone as any of us expected... the forum is richer for the teachings!

AW111

9,455 posts

132 months

Friday 24th February 2017
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GreenV8S said:
The deduction that seems most obvious to me is that when you say 'full' you don't actually mean as full as it could ever possibly be - only that it has reached what the designer considers the optimum for that particular engine design. Remember that I'm not asking whether a smaller capacity could produce more power or torque, but whether it could produce more power or torque per liter.
There must be a practical limit for a NA engine, regardless of # of valves :
Assume 105% VE as a start, and best AFR for peak power. Surely the torque is ultimately limited by the amount of fuel you can burn? There are gains to be made by reducing friction, and playing with timing and compression, but there is still a limit somewhere.

AFAIK, in the days when F1 ran on special-brew jungle juice, a lot of the clever chemistry in the fuel was tailoring burn rates to get the best combustion pressure profile. Every little bit helps.

Mignon

1,018 posts

88 months

Friday 24th February 2017
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Guy Stevens said:
Hi All
I have carried out a fair amount of work on this car during its current ownership. The engine that was in the car when it was purchased was removed and replaced with a 3.5 ltr engine built by John Eales. The engine has just been freshened up hence the visit to the rolling road. I can confirm that it is indeed still 3.5 ltr.
Regards
Is there a prize for top lurker on PH? 15 years and finally one post supporting something that only the OP in here seems to believe?

A number of questions spring to mind.

If the car had a dry sumped 4.5 litre engine in it why would anyone take that out and put a 3.5 litre dry sumped engine in? Lots of money for lots less power and torque.

Given that the 3.5 V8 has been obsolete for years, it's probably not even easy to find one now, and hardly anyone builds anything less than a 3.9 these days which costs no more to build - why a 3.5? In fact the 4.6 cross bolted engine is probably about the best bang for buck.

You don't state categorically you are the new owner and you clearly aren't the engine builder so why should we believe you "know" it's a 3.5 engine?

Just musing.

geeks

9,119 posts

138 months

Friday 24th February 2017
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I love reading threads like this, gives me an appreciation for just how little I know about engines. I consider myself mechanically capable and know gudgeon pin from a piston ring and how an engine works, what knock is, how to bolt it all together and hide the evidence of left over bolts etc but you guys are in a different league!

On the plus side reading it all means I done do learn stuff smile