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Dammit
Spa-Francorchamps


Joined: 23 Sep 2016
Posts: 364



PostPosted: Sun Jun 18, 2017 9:42 pm    Post subject: Benchrace 2,000 Reply with quote

WARNING: nothing is going to happen in this thread bar (largely uninformed) speculation until probably 2020.

I bought my 996.1 on just over 60,000 miles last September, it's on 63,000 miles now, putting me on course for my expected 5,000 miles/year.

Combine that with my desire to get Hartech to rebuild the engine at ~80,000 miles and you have the reason why nothing is going to happen for a few years.

I also had the engine bore-scoped, leak-down and compression tested at the recent engine-out service and it got a rude bill of health.

SO - as I said, speculation, but also an honest request for those with more knowledge than myself (this is most people I suspect) to comment.

Why am I planning on getting the engine rebuilt at 80,000 miles? Largely because Baz says that this is a fairly decent point to do so - before you might need a new crank due to bearing shell wear, essentially.

Whilst Hartech have the car I'd like them to upgrade the engine to their 3.7 litre design, this is going to involve increasing the bore when they replace the barrels, therefore new pistons will feature also.

I'd also get their new IMS bearing, IMS sprocket and so forth. All fairly standard.

Now - speculation. Bumping the engine up by .3 litres will give me a little more torque, possibly a little more power at the upper end also.

I'd like to see if I could push this a little further by using the X51 heads and intake system. I'll likely go for less restrictive cats and manifolds as well.

I'd also like to go for the oiling and cooling modifications that are part of the X51 upgrade.

Please see GT4's excellent thread here for more details on the X51: http://www.911uk.com/viewtopic.php?t=60293

Now GT4 was good enough to ask an OPC how much the full kit of parts to upgrade a standard car to X51 was, recently:

Parts only = £15,834.30

I need to follow up on this in order to understand whether I need all of that - for example I believe it includes manifolds and cats and I may be better served getting these elsewhere. At the moment I don't know.

This is, fairly obviously, going to be expensive - but it's three years away so I can accumulate parts over that period so it won't be one huge bill.

I await your howls of derision.
 
  
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Fastlane
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Joined: 05 Mar 2017
Posts: 61
Location: Truro


PostPosted: Mon Jun 19, 2017 8:37 am    Post subject: Reply with quote

I can sort of understand your thinking, but only if you are thinking of keeping the car long term. I'm not sure the X51 package is a cost effective way of achieving increased power these days though.

Incidentally, the March 2017 issue of 911 & Porsche World has an article on modified 996s. It features Autofarm's 3.9 litre Silsleeve-engined 996.2 and quotes 385bhp and 332lb ft. It also mentions a figure of 15k, but that seems cheap - I would assume nearer 20k.

Sounds like you've got a lot of research to do, should be fun! Good luck.
_________________
2001 Zanzibar Red 996.1 C4
Factory Options: Cup Aerokit, Non-Sunroof, Sport Design Wheels, M030, PSE, Sports Seats, Carbon Handbrake and Gear Knob, 3 Spoke Steering Wheel.
Modifications: Topgear manifolds, DesignTek SuperSound Mufflers, 997 GT3 shifter

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Dammit
Spa-Francorchamps


Joined: 23 Sep 2016
Posts: 364



PostPosted: Tue Jun 20, 2017 2:55 pm    Post subject: Reply with quote

Certainly plenty of research to do, but lots of time in which to do it.

X51 engine kit pn 000 044 100 09 comprising of:
1 - 000 044 100 10 Piston Set
1 - 000 044 100 11 Gasket Set
1 - 996 104 982 01 Cylinder Head
1 - 996 104 983 01 Cylinder Head
1 - 996 110 980 00 Intake Manifold
1 - 996 110 983 00 Intake Manifold
1 - 996 105 991 00 Camshaft
1 - 996 105 992 00 Camshaft
1 - 996 105 996 00 Camshaft
1 - 996 105 997 00 Camshaft
1 - 996 106 037 51 Oil Cooler
1 - 996 107 988 00 Oil Pan
1 - 996 111 991 01 Exhaust Manifold
1 - 996 111 992 01 Exhaust Manifold
1 - 996 575 141 02 Duct
1 - 996 106 665 55 Hose
1 - 996 106 641 59 Hose
1 - 996 106 666 52 Hose
1 - 996 107 980 00 Oil Pump
24 - 996 105 994 00 Cam Follower
2 - 996 110 985 01 Elbow
1 - 996 107 984 02 Hose
1 - 996 573 980 00 Hose
2 - 996 107 221 51 O-Ring
1 - 996 104 995 00 Heat Shield
2 - 900 075 495 00 Bolt Kit
1 - 996 504 485 02 Bracket
1 - 996 504 487 02 Bracket
1- 996 505 553 05 01C Lower Valance

And here's a picture as we all love pictures:

 
  
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Dammit
Spa-Francorchamps


Joined: 23 Sep 2016
Posts: 364



PostPosted: Fri Jun 23, 2017 1:42 pm    Post subject: Reply with quote

And now with the list broken up into sections, and pricing (no VAT):



No getting away from the fact that the heads and the cams represent a lot of money, the exhaust manifolds don't, I believe, stack up - other options at a much lower cost are available.

In terms of the cooling parts the vast majority of the cost is in the new oil pump, all of that looks fairly reasonable, but would also potentially duplicate some stuff that Hartech would provide so we'll leave that to one side for the moment.

I have a Cargraphic exhaust at the moment so might look to them for their manifolds and 200 Cell X-pipe setup, which would give me an entire system made by the same manufacturer - hopefully that would be beneficial from a fit perspective.

Now how can I get the price of the heads and the cams down a little?
 
  
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DynoMike
Barcelona


Joined: 25 May 2012
Posts: 1252
Location: The Cotswolds

2003 Porsche 996 Turbo

PostPosted: Fri Jun 23, 2017 9:29 pm    Post subject: Reply with quote

To get the cost of the heads down get them ported, a good head man will get a nice flow bench backed increase in airflow Laughing

For cams take a look at, say, Schrick for some alternatives. I understand that Porsche cams can be reprofiled and still keep the hydraulic tappets happy, which would make a saving. The best company in the UK to do this are Piper Cams, they have proper kit in the form of a Berco-Lynx cnc cam grinder, but most importantly they have a very good cam designer. I can ask him about the possibility of reprofiling your cams if you want? No promises that he can do it though!

Head and cam work would make a sizeable difference if done properly.
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Dammit
Spa-Francorchamps


Joined: 23 Sep 2016
Posts: 364



PostPosted: Fri Jun 23, 2017 9:41 pm    Post subject: Reply with quote

That's very interesting - do you think we could get the same results as the X51 parts attain by porting the existing heads? Would new, larger valves be desirable/required?

If the best results would be X51 then I'll go that route, but if we could get the same (or better) results by going a different, more affordable route then that makes sense.

I do quite like the provenance of the X51 stuff, which counts toward it, if that makes sense?
 
  
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DynoMike
Barcelona


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Posts: 1252
Location: The Cotswolds

2003 Porsche 996 Turbo

PostPosted: Fri Jun 23, 2017 10:38 pm    Post subject: Reply with quote

Dammit wrote:
That's very interesting - do you think we could get the same results as the X51 parts attain by porting the existing heads? Would new, larger valves be desirable/required?



I do quite like the provenance of the X51 stuff, which counts toward it, if that makes sense?


In answer to part one, I would imagine that the end results would be very good if properly done. Bigger valves would raise the costs, tipping the balance back towards the X51 route. The larger cylinder bore will give greater flow due to unshrouding of the valves, a common by-product when going to over bored cylinders. Sometimes the chambers can be opened around the valve with positive results, the flow bench tells all in this regard.


Only you can decide regarding part two of your post.
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Dammit
Spa-Francorchamps


Joined: 23 Sep 2016
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PostPosted: Fri Jun 23, 2017 11:09 pm    Post subject: Reply with quote

My Volvo is highly modified, it's had extensive engine (including head) work and is reliably producing 150% of the power that it left the factory with - and could produce a lot more with a larger turbo, it would just need new water lines and a re-work of the downpipe mating flange. So - the work, well, worked. But this has meant a lot of custom stuff, and if I were to take it to a standard Volvo dealer with something serious wrong with it I imagine I'd get a lot of shrugging and "we're not sure what's going on there".

Now don't get me wrong - the Volvo project was fun. But it's tied me to one chap in the Midlands who knows the car backwards, and did all the work.

The appeal of the X51 stuff is that it's off the shelf, and if by going custom we're only going to equal what we'd achieve with X51 then I'd rather go for something that can be replaced by picking up the phone to an OPC and waiting 24 hours, anywhere in the world.
 
  
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Dammit
Spa-Francorchamps


Joined: 23 Sep 2016
Posts: 364



PostPosted: Sat Jun 24, 2017 11:28 am    Post subject: Reply with quote

This is quite interesting, from Porsche 996, The essential companion by Adrian Streather:

Installing option X51 the engine power upgrade kit creates the M96/01S engine, which differs from the standard engine in the following areas:

- Power and torque increased to 320 bhp and 266 lb-ft
- Six new pistons with modified valve recesses installed
- Four new camshafts with greater cam stroke installed
- Two new reduced height cylinder heads with modified cross-section, optimised inlet ports (polished), modified top valve disc, outside valve springs, bottom valve disc, shortened valve guides and modified valves installed
- Two versions of the modified valves are used in the option X51 kit. The first version was used up until November 1998 and consisted of standard valves fitted with additional valve caps. After November 1998 completely new valves were used. The new valves are 1.5mm longer than the standard versions, have the valve caps removed and are identified by a yellow dot on the inlet valve disc and a black dot on the exhaust valve disc
- A dual chamber suction pump, sealed by two sealing rings is fitted to cylinder head bank 4 to 6
- An oil suction pipe is fitted between the dual-chamber suction pump and the cylinder head cover
- A take-up bore for the oil suction pump is also added to the cylinder head cover of bank 4 to 6
- New oil pump part number 996.107.980.00 supplied with the kit
- A new oil pan with a metal partition box (bale) replaces the standard version which has a plastic partition box
- The exhaust ducts are enlarged requiring a larger exhaust manifold gasket and a new set of exhaust manifolds
- The air conditioning compressor suction line is modified
- Intake pipes are modified to follow the internal contours of the inlet ducts on the new cylinder heads
The left and right air intake distributors are replaced with new cast units.
- Idle speed raised to 800 rpm, rev limit raised to 7,400
 
  
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Dammit
Spa-Francorchamps


Joined: 23 Sep 2016
Posts: 364



PostPosted: Sat Jun 24, 2017 11:32 am    Post subject: Reply with quote

I highlighted the valve recesses part of that, as it suggests to me that the new, Hartech 3.7L pistons may be something of an interference fit as they are designed for the standard heads, which would be sub-optimal.

I suppose that this is a good reason to get all the parts up to Hartech well before needed so they can have a play with them.

The X51 kit makes 94.5hp/L on the 3.4, which would be interesting if that is maintained with the new larger displacement. (X51 on the 3.6 made 95.8hp/L)
 
  
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DynoMike
Barcelona


Joined: 25 May 2012
Posts: 1252
Location: The Cotswolds

2003 Porsche 996 Turbo

PostPosted: Sat Jun 24, 2017 8:57 pm    Post subject: Reply with quote

Dammit wrote:
This is quite interesting, from Porsche 996, The essential companion by Adrian Streather:

Installing option X51 the engine power upgrade kit creates the M96/01S engine, which differs from the standard engine in the following areas:

- Power and torque increased to 320 bhp and 266 lb-ft
- Six new pistons with modified valve recesses installed
- Four new camshafts with greater cam stroke installed
- Two new reduced height cylinder heads with modified cross-section, optimised inlet ports (polished), modified top valve disc, outside valve springs, bottom valve disc, shortened valve guides and modified valves installed
- Two versions of the modified valves are used in the option X51 kit. The first version was used up until November 1998 and consisted of standard valves fitted with additional valve caps. After November 1998 completely new valves were used. The new valves are 1.5mm longer than the standard versions, have the valve caps removed and are identified by a yellow dot on the inlet valve disc and a black dot on the exhaust valve disc
- A dual chamber suction pump, sealed by two sealing rings is fitted to cylinder head bank 4 to 6
- An oil suction pipe is fitted between the dual-chamber suction pump and the cylinder head cover
- A take-up bore for the oil suction pump is also added to the cylinder head cover of bank 4 to 6
- New oil pump part number 996.107.980.00 supplied with the kit
- A new oil pan with a metal partition box (bale) replaces the standard version which has a plastic partition box
- The exhaust ducts are enlarged requiring a larger exhaust manifold gasket and a new set of exhaust manifolds
- The air conditioning compressor suction line is modified
- Intake pipes are modified to follow the internal contours of the inlet ducts on the new cylinder heads
The left and right air intake distributors are replaced with new cast units.
- Idle speed raised to 800 rpm, rev limit raised to 7,400



It sounds as though the standard valves had lash caps on the top of them (valve caps) which they removed, saving weight. This reduces the chance of separation at high rpm or any area where spring surge could take place.

The thinner heads were skimmed versions I suggest, in order to bump the compression up. Your heads can be skimmed but they will be heat treated. We skim many heads for local garages, most modern vehicles seem content with up to 0.5mm off them, any more and the heat treated layer is breached and the head may become unreliable in terms of holding a gasket. However, with a high displacement there may be less need for high CR.

When viewed in context of the above list of yours, they represent pretty good value at the price point, particularly as they will have had zero thermal cycling and no water jacket corrosion of any form.

I would imagine Hartech are pretty savvy and may have allowed a little more valve clearance at the design stage, Baz is obviously the guy to ask.

100hp/litre should be relatively drama free given suitable cams and the available valve area. An interesting project for you.
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Dammit
Spa-Francorchamps


Joined: 23 Sep 2016
Posts: 364



PostPosted: Sat Jun 24, 2017 9:08 pm    Post subject: Reply with quote

Thanks Mike, very much appreciate your input.

I'm aware of how little I know about all this - the educational aspect of these projects is part of the appeal.

On the 850R I have a 100 cell race cat, which has passed the emissions test every year with no problems - does this experience mean that a pair of 100 cell cats for the 911 would be fine for passing MOT's?

I noticed that the CLR has 200 Cell cats, which made me wonder.
 
  
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Dammit
Spa-Francorchamps


Joined: 23 Sep 2016
Posts: 364



PostPosted: Wed Jun 28, 2017 4:12 pm    Post subject: Reply with quote

I received an email from Baz at Hartech today which made for interesting reading - his view is that the X51 heads are not going to make a big difference and that it would be better to take the oiling and exhaust modifications from the kit, put those with the 3.7 increase, and that would be an ideal combination of funds, time and energy.

This does make things rather a lot cheaper, of course.
 
  
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DynoMike
Barcelona


Joined: 25 May 2012
Posts: 1252
Location: The Cotswolds

2003 Porsche 996 Turbo

PostPosted: Wed Jun 28, 2017 9:20 pm    Post subject: Reply with quote

Baz will know the true benefit of the heads, so it's good to have his input on the X51 versions.

Going back to standard heads for a moment, any time displacement is increased the port velocities also increase at any given rpm. The nett effect is that peak torque is produced at lower rpm and peak power rpm is also lowered. If larger cams are used in conjunction with properly proportioned ports, the rpm values for peak torque/power can be brought back to standard, or raised further still.

As a general rule of thumb, any time a larger bore is put under the same valve area, the engine will feel more muscular and urgent in it's power delivery. There is good reason why our Colonial cousins coined the saying 'Ain't No Replacement For Displacement'!
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Dammit
Spa-Francorchamps


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PostPosted: Wed Jun 28, 2017 9:32 pm    Post subject: Reply with quote

Baz had this to say:

"The X51 equipment is a typical way to make an existing engine capacity flow more air and produce more torque but the limiting factor is always at higher revs because the time to fill and excavate the cylinders is less (in inverse proportion i.e. half the time at 7000 rpm that there is at 3,500 rpm)).

If you are not going to change the capacity then the only way to get more performance is to increase the breathing with hotter cams and bigger inlets etc.

However if you increase the capacity it increase the pressure differential on breathing (because you have a bigger piston sucking in and forcing out the inlet air and exhaust) and so it manages to flow more air through the existing cams, ports and valves. It hardly flows any more at peak revs but then the air that is trapped and the burning fuel create a similar BMEP but push down on a larger diameter piston area – so still produce more power (although the main benefit is in the mid range where the car works between gear changes).

Any engine system is balanced so the restrictions are about the same throughout the inlet and exhaust (i.e. there is no one part restricting all the others). By increasing the capacity you help flow the air through existing well balanced components better. However a bigger exhaust manifold and exhaust system may well offer some small advantage."

I'd like the character of the engine to be that it keeps making power to the rev-limit, rather than a turbo-diesel-esque massive mid-range and then strangling as the revs rise.

I admit that I have no idea how to go about calculating what cam-profile would be appropriate to take advantage of the displacement increase.

You mentioned Piper before, do you think they would be interested/able to do this?
 
  
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ragpicker
Sepang


Joined: 14 Apr 2013
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PostPosted: Wed Jun 28, 2017 9:32 pm    Post subject: Reply with quote

@ Dammit - you've got the ear of one of this forum's true engine genius' here in DynoMike, what he doesn't know about engines, cylinder heads, valves, air flow, engine mapping (and a myriad of other things) isn't worth knowing.

Once again the depth of knowledge demonstrated on this forum leaves me discombobulated Embarassed
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thecarfixer
Trainee


Joined: 03 Nov 2016
Posts: 72



PostPosted: Wed Jun 28, 2017 9:47 pm    Post subject: Reply with quote

Dammit wrote:
Baz had this to say:

"The X51 equipment is a typical way to make an existing engine capacity flow more air and produce more torque but the limiting factor is always at higher revs because the time to fill and excavate the cylinders is less (in inverse proportion i.e. half the time at 7000 rpm that there is at 3,500 rpm)).

If you are not going to change the capacity then the only way to get more performance is to increase the breathing with hotter cams and bigger inlets etc.

However if you increase the capacity it increase the pressure differential on breathing (because you have a bigger piston sucking in and forcing out the inlet air and exhaust) and so it manages to flow more air through the existing cams, ports and valves. It hardly flows any more at peak revs but then the air that is trapped and the burning fuel create a similar BMEP but push down on a larger diameter piston area – so still produce more power (although the main benefit is in the mid range where the car works between gear changes).

Any engine system is balanced so the restrictions are about the same throughout the inlet and exhaust (i.e. there is no one part restricting all the others). By increasing the capacity you help flow the air through existing well balanced components better. However a bigger exhaust manifold and exhaust system may well offer some small advantage."

I'd like the character of the engine to be that it keeps making power to the rev-limit, rather than a turbo-diesel-esque massive mid-range and then strangling as the revs rise.

I admit that I have no idea how to go about calculating what cam-profile would be appropriate to take advantage of the displacement increase.

You mentioned Piper before, do you think they would be interested/able to do this?


Look at Schrick cams - they do a few profiles for the M96..
 
  
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Dammit
Spa-Francorchamps


Joined: 23 Sep 2016
Posts: 364



PostPosted: Wed Jun 28, 2017 9:54 pm    Post subject: Reply with quote

DynoMike mentioned those also, I'm just unsure what to look for - 3.4L heads on a 3.7L engine. Which cams would that logically mean I should look at - the 3.6? But that's Variocam+ whereas my engine is Variocam.

I've run headlong into the limits of my own ignorance, unfortunately.
 
  
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poppopbangbang
Nürburgring


Joined: 25 May 2015
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PostPosted: Wed Jun 28, 2017 9:55 pm    Post subject: Reply with quote

DynoMike wrote:
Baz will know the true benefit of the heads, so it's good to have his input on the X51 versions.

Going back to standard heads for a moment, any time displacement is increased the port velocities also increase at any given rpm. The nett effect is that peak torque is produced at lower rpm and peak power rpm is also lowered. If larger cams are used in conjunction with properly proportioned ports, the rpm values for peak torque/power can be brought back to standard, or raised further still.

As a general rule of thumb, any time a larger bore is put under the same valve area, the engine will feel more muscular and urgent in it's power delivery. There is good reason why our Colonial cousins coined the saying 'Ain't No Replacement For Displacement'!


This absolutely 100 times over!

People always miss how critical port velocities are - it is not just about bulk flow figures from a flow bench. If you look at my 3.7L motors output:



You can see it makes peak power around 500rpm earlier than a standard car does and after 6500RPM power is dropping off fairly quickly. It also demonstrates why simply saying you'll only gain midrange torque is fairly wrong as the cylinder filling in many regimes will be better with a larger bore than it was originally due to the higher port velocities and this is without taking into account that the shrouded sections of the valves (i.e. those close to the bore wall) will be deshrouded slightly by the larger bore which whilst on the short side of the port can still provide flow/filling benefits.

I've just finished mapping a 3.8L HB F1 motor which is a 300CC increase on the standard motor achieved in a similar way to 3.7L conversions on the M96 engine. Peak power on this motor moved down by 700RPM over a good standard motor (peak at 11.9K vs 12.6K) but it made more power everywhere than any other HB before it and comfortably exceeded the best 3.5L motors peak figures by a long way.
 
  
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DynoMike
Barcelona


Joined: 25 May 2012
Posts: 1252
Location: The Cotswolds

2003 Porsche 996 Turbo

PostPosted: Wed Jun 28, 2017 10:15 pm    Post subject: Reply with quote

Um, thanks @ragpicker Embarassed , but you medical folks are the true genius' in my opinion - I for one wouldn't be here but for the brilliant work of you Doctors worship

Back on topic, Baz has said the same as I did above but in expanded format. As displacement goes up, pumping losses go up once the port and valve heads preferred mean gas velocity is surpassed. To elaborate, many engines require vastly different mean port velocities in order to produce their best power outputs. For example, way back in the eighties when the 6R4 Metro rally engine was conceived, the Clubman engine ran perfectly happily with a mpv of 107m/s at peak power rpm, whereas the International engine ran a mpv of 90m/s.

Fast forward to 2010-ish, we were raising very high specific power output motorcycle mpvs to >130m/s with excellent results. Specific power outputs of 227 hp/litre or more were achieved by making the ports smaller, not bigger. The key was increasing flow by filling and reshaping the ports, with constant testing and re-testing on the flow bench and engine dyno and matching cam profiles to the heads.

The key to unlocking performance in any given engine is finding what that particular engine likes as a mean port velocity value. With valve head based mean gas velocity, the old go-to number was 75m/s. This still works well but many modern engines will run happily to 82m/s with the smaller valves not hindering power outputs.

In short, the manufacturer will be reasonably on the money with the original proportions of the port/valve/piston area etc in standard form but improvements can be made, especially when presenting more cylinder capacity under a given head/intake/exhaust combination. Hours of fun!
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