Fancy a 2+bhp increase for nothing ?

[johnnyXS]

How many of you read the fascinating article by Darrel Taylor on basic budget tuning in May edition of Scootering ?

I bought the mag on a whim a couple of weeks ago to take with me for a Hospital appointment. I don't know about you but the thought of handling Hospital magazines fills me with terror when I think about all the germs that must cover them yuk... As I got seen right away I never did get to read the mag until today.....anyway I digress.

If you haven't read the article I strongly recommend that you do so. It won't perhaps appeal to those that prefer to spend lots of money bolting on new shiny performance bits but for those of us, like me, that like to understand how things work and get the most out of what you've already got , its a real eye opener.

Just by measuring the squish accurately and reducing it slightly Darrel found an extra 2.2bhp ! and 0.6 torque ! Thats staggering. If you bear in mind that a new series 3 Li150 was reckoned to have 6.6 BHP output.
An increase of 2.2 bhp would match a new SX150 or a GP150 or almost the output of a series 3 TV175 ! potentially for nothing more than getting your squish right.

How about this shocker. Replacing the standard 22mm carb for a 26mm one and rejetting on a dyno produced zero appreciable gain in power on a standard Sil 200 engine !

The article is to be part of an ongoing series and I cannot wait to read it.

[MickYork]

I must admit I was a bit reluctant to buy Scootering and thought it in demise, but the last few editions have sparked new life into the magazine and this (IMO)is mainly due to the "technical" articles. I say technical, but these are generally written in laymans terms ......... and the pictures help !!

[Adam_Winstone]

Agree 100%, this is a fascinating insight into what is possible with stage by stage attention to detail. I also remember a quote somewhere from Dave Webster or Ralph Saxelby that their take on tuning was to get the biggest return for the smallest changes first, which reminds me of this attention to detail approach.

Johnny, don't overlook the fact that a main reason for addressing the squish in this feature was that the compression was low and the 1.5 squish reduction bumped up the compression to a better figure, rather than it just being about getting the squish right.

A great read and I'm aware that the second part of this should be out now and I'm itching to read it

Adam

[johnnyXS]

Agree 100%, this is a fascinating insight into what is possible with stage by stage attention to detail. I also remember a quote somewhere from Dave Webster or Ralph Saxelby that their take on tuning was to get the biggest return for the smallest changes first, which reminds me of this attention to detail approach.

Johnny, don't overlook the fact that a main reason for addressing the squish in this feature was that the compression was low and the 1.5 squish reduction bumped up the compression to a better figure, rather than it just being about getting the squish right.

A great read and I'm aware that the second part of this should be out now and I'm itching to read it

Adam

I hadn't forgotten Adam . Squish and compression are synonymous and cannot be considered seperately, any change in squish will result in a change of compression naturally . I suppose the point that I was trying to put across was that with a little attention to basic detail there are potentially massive gains in performance to be had for nothing by all of us.
How many of us diy engine builders measure and set their squish accurately or even appreciate the effect of compression ? for that matter how many of us could quote the compression figure for their engines 1 in a 100 ? probably less than that, yet I'm willing to bet that 95% of those same owners have spent a lot of money on expansion boxes and bigger carbs in pursuit of power .

Engine building and performance is all about understanding how things work just as much as attention to detail .

Your reference to the old adage 'do the things that cost the least and gain the biggest performance increase first ' is so often overlooked these days.
its much more sexy to bolt on some really expensive shiny bling rather than get your points and staic timing set up accurately. Alexander Graham Bell and David Vizard were both exponents of this approach as far back as the 60's .

[holty]

Agree 100%, this is a fascinating insight into what is possible with stage by stage attention to detail. I also remember a quote somewhere from Dave Webster or Ralph Saxelby that their take on tuning was to get the biggest return for the smallest changes first, which reminds me of this attention to detail approach.

Johnny, don't overlook the fact that a main reason for addressing the squish in this feature was that the compression was low and the 1.5 squish reduction bumped up the compression to a better figure, rather than it just being about getting the squish right.

A great read and I'm aware that the second part of this should be out now and I'm itching to read it

Adam

I hadn't forgotten Adam . Squish and compression are synonymous and cannot be considered seperately, any change in squish will result in a change of compression naturally . I suppose the point that I was trying to put across was that with a little attention to basic detail there are potentially massive gains in performance to be had for nothing by all of us.
How many of us diy engine builders measure and set their squish accurately or even appreciate the effect of compression ? for that matter how many of us could quote the compression figure for their engines 1 in a 100 ? probably less than that, yet I'm willing to bet that 95% of those same owners have spent a lot of money on expansion boxes and bigger carbs in pursuit of power .

Engine building and performance is all about understanding how things work just as much as attention to detail .

Your reference to the old adage 'do the things that cost the least and gain the biggest performance increase first ' is so often overlooked these days.
its much more sexy to bolt on some really expensive shiny bling rather than get your points and staic timing set up accurately. Alexander Graham Bell and David Vizard were both exponents of this approach as far back as the 60's .

i agree with all of the above, optimising your squish will deliver more power and torque right across the rev range, making the engine seem bigger in capacity, it should also run cooler, giving better fuel consumption as well. i did at one time have a taffspeed 240 which ran very badly, hard to start, siezed a lot, in the end i stripped it,the piston was badly worn,i took the barrel to beedspeed were mark broadhurst honed the barrel and sold me a new piston and head profiled to the piston, i cant tell you the transformation of that engine by just getting the squish correct shape and thickness, had more power everywhere in the rev range, unbelivable improvement, so fast i crashed the bloody thing. i did go on to own a mini and tuned it myself using a book by david vizard as mentioned above, very clever man.

[johnnyXS]

240cc Taffy ? jeez Holty that thing must have flown...

its a long time ago now maybe 30+ years but one of those two writers wrote on tuning Datsun 240Z engines and I have several ancient Vizard and Bell tuning books stored away somewhere .
I can't wait to start rebuilding my LiS small block 200 engine and putting it all into practice with a Lambretta engine.
I hope that Darrel also covers timing and electrics too. It amazes me how many scoots I hear running on youtube that sound like they are being strangled with incorrect timing and a flat throttle response

[Charliebubble47]

Agree 100%, this is a fascinating insight into what is possible with stage by stage attention to detail. I also remember a quote somewhere from Dave Webster or Ralph Saxelby that their take on tuning was to get the biggest return for the smallest changes first, which reminds me of this attention to detail approach.

Johnny, don't overlook the fact that a main reason for addressing the squish in this feature was that the compression was low and the 1.5 squish reduction bumped up the compression to a better figure, rather than it just being about getting the squish right.

A great read and I'm aware that the second part of this should be out now and I'm itching to read it

Adam

I hadn't forgotten Adam . Squish and compression are synonymous and cannot be considered seperately, any change in squish will result in a change of compression naturally . I suppose the point that I was trying to put across was that with a little attention to basic detail there are potentially massive gains in performance to be had for nothing by all of us.
How many of us diy engine builders measure and set their squish accurately or even appreciate the effect of compression ? for that matter how many of us could quote the compression figure for their engines 1 in a 100 ? probably less than that, yet I'm willing to bet that 95% of those same owners have spent a lot of money on expansion boxes and bigger carbs in pursuit of power .

Engine building and performance is all about understanding how things work just as much as attention to detail .

Your reference to the old adage 'do the things that cost the least and gain the biggest performance increase first ' is so often overlooked these days.
its much more sexy to bolt on some really expensive shiny bling rather than get your points and staic timing set up accurately. Alexander Graham Bell and David Vizard were both exponents of this approach as far back as the 60's .

i agree with all of the above, optimising your squish will deliver more power and torque right across the rev range, making the engine seem bigger in capacity, it should also run cooler, giving better fuel consumption as well. i did at one time have a taffspeed 240 which ran very badly, hard to start, siezed a lot, in the end i stripped it,the piston was badly worn,i took the barrel to beedspeed were mark broadhurst honed the barrel and sold me a new piston and head profiled to the piston, i cant tell you the transformation of that engine by just getting the squish correct shape and thickness, had more power everywhere in the rev range, unbelivable improvement, so fast i crashed the bloody thing. i did go on to own a mini and tuned it myself using a book by david vizard as mentioned above, very clever man.

Didn't see the article so how would be the best way to test and optimise the squish and can this be done with the engine insitu

Cheers
CB

[Eden]

Reducing the squish makes the compression higher which of course will increase power.
It also increases squish velocity which increases the rate and quality of the combustion burn.

Its really not rocket science

People tend to make it sound like it though lol

[johnnyXS]

thats the thing Eden.....seems like the more I read about it the more I appreciate that squish is a science.

I suspect that the majority of scooter owners have never heard of squish and even fewer have a real understanding of what it is or how it effects the performance and reliabilty of their engines.. Thats why I think Darrels series is so important for diy mechanics who perhaps have little technical knowledge and little experience.

Do you know what the peak squish velocity is for any of your engines and why its important to know ? I know I don't lol

I wonder how many of us could state which type of squish our pistons and heads have,... the direction of flame travel , ...recommended minimum squish allowance etc.

I'm really looking forward to learning lots more about this and the other topics in this series.
If simply adjusting my squish could potentally give me a 1-2bhp increase for £0.00 ..... I want it

[Eden]

Do you know what the peak squish velocity is for any of your engines and why its important to know ? I know I don't lol

Yes, I machine my heads myself to achieve a certain velocity at a certain RPM.

I haven't read the article as I dont buy scootering mag or buy into its ethos so I have no idea what Darrel says in it.

Does he mention that the velocity is chosen depending on how the motor is intended to be used?

[johnnyXS]

[

I haven't read the article as I dont buy scootering mag or buy into its ethos so I have no idea what Darrel says in it.

Does he mention that the velocity is chosen depending on how the motor is intended to be used?

Ahh well you had better get a copy eden:lol:

No he doesn't mention anything about squish velocity. Its an article aimed at the average scooter owner who wishes to understand a little about how their engine works so its unlikely to be at that level...........I hope not anyway or it will be over my head

I should imagine that the squish characteristics of any given engine are likely to be determined primarily by the engine components and performance characteristics both of which in turn would presumably have been selected based on how you intend to use the scooter .

[Dimitrios_231]

Latest issue has a MSV (maximum squish value) article.

[xenia1]

Blue printing an engine will also help release power as well as improving reliability..

[johnnyXS]

Critique

Well I don’t mean to be critical, (ok I do lol) but the latest bang for Buck installment this month has left me feeling confused and dissapointed. Is this to be an article about Bang for buck Tuning ....or an expensive scooter upgrade article ?

This months installment begins with a 2x paragraph 200+ word introduction and recap of last months installment which is surely unnecessary . Anyone vaguely interested in this tuning series will either already have last months magazine or will make it their business to obtain a copy of the article.

This is followed by a 3x page perfunctory breeze through a complete scooter upgrade ? The upgrade article reads to me like it has been a last minute after thought . It lacks detail and references and is very cursory. Yes of course there is a need to upgrade everything to cope with the substantial power increases but surely it would be better to make that subject of a seperate article just as is the fascinating article about Squish.

‘In my garage we had a basic rule of thumb ‘ .....Just who is writing this article anyway?

The text continually switches between the first second and third person which leaves the reader very confused as to who is actually the author of this article !. If it is a collaborative effort then it should say so .

I have been led to believe that the article was to be solely the subject of Darrels testing, observations and experience yet the majority of the opinions and recommendations appear to be that of the writers and they are largely unsubstantiated and without reference.?

The second picture has an array of standard parts that presumably were fitted to the test bed of this article, a standard Sil 200 engine . The likely cost of upgrading just those items alone would likely run to £700+ then there is the exhaust which could add a further few hundred pounds and we haven’t even touched upon the electrics and ignition upgrades .

The third image shows a pair of inlet manifolds with the caption ‘Flowed inlets –myth or magic’ despite scanning through the complete article several times I failed to find any reference to this anywhere so I’m left wondering what this is about, presumably the subject of a future article ?

At this early stage of the series it would appear to me that we are investing well over £1500 already in upgrades and I am left wondering just where our ‘Bang for Buck’ has gone ...

[dickie]

Johnny, Johnny, Johnny.

They're just stupid old shopping mopeds and we dick around with them for fun.

Is it really necessary to analyse the article as if it were a PhD thesis?

Some view the changing way we use our language as a lowering of standards; others view it as natural evolution. Innit!!!??

Everything you say is correct (I was particularly puzzled by the flowed inlet manifolds too), but I still enjoyed reading it.

[johnnyXS]

I feel the main thing that is lacking in this article is some sort of direction and objective . We have no idea really what the main objective is or how we are going to reach it. In just two short articles we have leapt from measuring squish accurately to bolting on ££ thousands of pounds worth of modern high performance parts ? Whats 'old skool 'about that ?

If the initial objective was to see how much power the Sil 200 engine would develop, it might have been prudent to start with an upgraded engine in the first place .

It also seems to me that the article is only looking at one aspect of performance tuning , (mechanical) and neglecting coverage of fuel and ignition.We know that the testing was carried out with a 22mm carb but what jetting was tested and used ? what sized inlet manifold ? what type of ignition system ? static and dynamic advance etc etc .

Generally when we look at engine tuning and performance we talk in terms of 'Stage' tuning ie tuning from stock to a series of stages . The key aspect of this is that each stage of tune is completely integrated including electrics, ignition, fuel and air delivery and flow etc etc . So far these articles have skipped over most of these aspects completely.

Suspension and braking upgrades are of course essential to keep in line with the extra performance but this series was I understood to be about old school performance engine tuning not upgrading the scooters brakes.

[Adam_Winstone]

I was a little disappointed too, in so much as I want to get into the 'meat' of the tuning process, testing and info. However, the feature is absolutely right in what it has done; highlight that building a tuned motor on weak foundations is a sure way to bring on early engine failure and put riders at risk.

Far too many people are only interested in performance and want it on the cheap, which is ok within reason but it quickly becomes an expensive hobby when you build up a motor on a crank that is known to fail in standard format, commonly taking the whole top end out when it does fail. Tuning on the cheap should not be confused with tuning on known sub-standard parts that are more than likely going to fail and cost you a lot more money, and heartache, in the long run.

Yes, I too was disappointed not to get any real info out of this 2nd part, however, I appreciate that I'd look to swap out the parts of an engine rebuild (especially tuned) in the same manner that the author has identified. What is obvious to me/you/many is not obvious to all so I think that it was a good step and the right step for the author to take, reminding all that you need to ensure that all is well before you start to make changes that will put additional stress on components.

As for the writing, I don't read tuning features for a lesson in penmanship... but you've probably already gathered that from the state of my ramblings

Here's to Part 3.

Adam

[johnnyXS]

yes I've no issues with the upgrading recommendation whatsoever as I said previously, however anyone seriously interested in diy performance tuning ought in my opinion to have the eighteen pence to appreciate the need to upgrade their brakes and suspension.

The magazine obviously need to cover themselves with various caveats like 'nutty bar ...it may contain nuts' I appreciate that however my point was, that the article about upgrading was too vague. if you are going to go into that amount of detail then you should in my view give options, references, links, sources, prices etc so that owners can obtain a full picture of what is required and how to go about it. .Either that or make a brief recommendation and reference to it with some helpful links and leave it at that. Too much was taken for granted about the upgrading in my view.The article was either too little or too much depending on your point of view.

Anyway my critique is not intended to be the basis of an argument but rather to raise some issues for discussion.

Perhaps I was just expecting something else which was hinted at in the original title of this series of articles .
quote:-
'Forget tuning exotica and spending frenzies - here's how to get more power for your pound '

[Adam_Winstone]

Agree with you Johnny and hope that this month's upgrade content might just be intended to make readers want the next part that much more... I know I do.

Adam

[johnnyXS]

a months a long time to wait Adam .........
(johnny checks his diary for the fifth time today)