Adam M

Andy I don't quite follow,

how comes if you skim the head you don't bring the head closer to the piston crown and hence affect the squish clearance?

Could understand if you had said remove some material from the head of the centre of the piston crown.

a little please explain.

Bob Rawle

Andy ... nice to see we are talking about the original topic, depending on the piston design it seems possible to vary gasket thickness to achieve the desired result, agree that in an ideal world pistons would/should be adjusted to suit. Glad to say mine appear to be "right" in that respect however thats probabably due to Matt Clark's Omega piston development rather than my theorising.

To say I have the opportunity to map a few cars using your turbo upgrades and if they are anything like the ones I have seen so far good results to be had.

The Omega pistons I am using have a totally different squish shape to the norm which is possibly an influence

cheers

bob

Andy.F

Thanks for the positive feedback on the turbo's Bob

Adam, The squish is measured from the raised outer edge of the piston to the flat face of the cylinder head ie the faces that would collide if the piston came too high. When you skim the head, this clearance is not changed. If you change the gasket thickness, it is.
The 'ideal' squish will vary even from car to car depending on piston material and design, even type of con rod used can change the stretch and hence squish at high RPM.
I'm not aware of any privateers that can affort the R&D required to optimise this fully for each individual engine spec. There are a few 'rules of thumb' but generally it is a case of stick within a range which you know has worked in the past !!

Andy

Bob Rawle

Andy ... credit where credit is due, glad to see some positive comment re squish. Commercial considerations rule most folk !!!

cheers

bob

Adam M

thanks for the explanation.

think my confusion came from the fact that I didnt realise that the flat area extended beyond the gasket area. I presumed it started to taper immediately above the piston area.

Design and squish clearance volume of mine to my knowledge is unchanged from JEs design for the low compression ej2.5.

Andy.F

Just to correct my post above, Harveys engine compression increase was achieved via a combination of head skimming and use of a thinner head gasket.

Andy

Adam M

I do hate saying it so often, but static compression ratio is only a number and is not really representative of what is actually going on when the engine is running.

Having said that, with all else equal as it was with harvey's, raising the static compression is going to yield the theoretical effects of higher compression, at least to some degree. I think it was the right move, having done the same myself.

Also think that the longer final drive on the car has transformed it entirely for the better and having had some time getting used to mine now, I am very happy with its performance.

7.5:1 compression is all very well, but if you can't fill and empty the cylinder it really doesn't mean anything at all, for this you need to consider the cam timing and the flow efficiency of the heads and all in the pipework.

It's also the reason why you can't simply mulitply up the power figures on a 2.0 by 1.25 to get the power figures of a 2.5 (I remember stating this in the past!), the output tails off enormously as a result of the increased cylinder volume and the associated difficulties in emptying and filling it.

David_Wallis

Harvey,

its all tongue in cheek..

The 600bhp came about with me thinking of my spec + nitrous..

Except two things have happent since then.. Ive got my engine and running 0.8 bar boost paul says it is as quick as tweenierobs car was if not quicker. (circa 400) I think its still pretty quick

Anyway Ill stop dribbling..

The car is quick and Im happy with it.. almost quick enough..

I was planning on using nitrous to boost the power but, *shock* *horror* it's quick enough without it, and the turbo spools earlier than I thought it would (not early but then it aint small)

so.. as for power... if get some spare time and can get time off work to get to bruntingthorpe then I'll try and get some more mapping done.. (also some cash to cover petrol fooking mapping eats petrol )

David

ustolemyname??stevieturbo

iTrader: (1)

Its never quick enough....dont be silly.

Andy.F

David

Tell me you didn't spend ALL that money for a car that's only as quick as a high mileage 2.0 running with a std frame turbo Get that boost cranked up and lets see what it can do at scooby shootout

Andy

David_Wallis

Trout

iTrader: (1)

Harvey,

the engine is being built by Steve at SMG.

As Steve does it alongside a full time job, and a build takes a little longer than the 20 hours being suggested elsewhere due to significant detail work being carried out - the engine - now all the components are in one place is taking some time.

This includes being pushed back in the queue as JBs engine had to be stripped and checked for valve and piston damage due to the failed cam tensioner that was fitted post-build.

As I say when I am up and running satisfactorily I will share more detail regarding the engine. The short block is nigh on identical to JBs and Wallis'.

One thought does occur to me however - you have stated in many of your posts the question as to why the build projects take so long - as you expect a build to be a couple of days. As you clearly state this case I am just wondering about your 'big build' as it says on your website that you started this project several months ago?

Rannoch

john banks

Didn't realise Steve wasn't full time... explains the timetables involved. I believe my engine is now en-route

It would be nice if everyone would settle down a bit and stop backbiting.

Andy F is not selling turbos on a large enough scale for anyone to be threatened, and he will also admit he is foremost an engineer and not really running a serious business. He likes to and always tends to win at any class he competes in and has a long history of this well before he entered the Subaru community. His ability for novel engineering solutions to problems other people don't even seem to recognise, and his all round ability as an engineer and a driver who can achieve his aims within a budget and blow everyone else away in the process are unparalleled in our community.

Mark Aigin is not to my knowledge living off the fat of the land selling duff products and services, but on the contrary has moved on the supply of some very interesting products and services to the Subaru community in the UK and sounds like he makes only a modest living out of it in a volatile and demanding market sector. It is quite astonishing how much in the way of products and services you have to sell to make anything like a living out of Subaru tuning. There are far less talented individuals box-shifting with poor after-sales service. Without the innovative products that are used successfully by many relatively uninformed members of the Subaru modifying public I think he is doing a good job. He has also had a hand in a number of exciting big engine conversions of Subarus which are still to be fair finding their feet (I include mine here). He has responded to the market needs for various turbo upgrades and been very flexible with many in meeting their growing needs.... he could easily just import Japanese branded turbos and sell them and cut himself a lot of hassle, but has tried to work on producing better performing items for a more sensible budget.

Harvey is a fabulous chap, only met him twice, spoken on the phone a few more times, very hospitable, passionate and informed about his Scoobies, and has an intuitive broad picture of how to make a Scooby do what he wants it to do right up there on the leading edge with the very best, drawing together the best from several suppliers.

There is no need for the conflict gents... work away at your own thing and enjoy it FFS. Life is complicated enough without this bizarre situation. You all have superb achievements, let them speak for themselves.

I personally feel a weight off my shoulders no longer being commercial (although I was never significant in terms of volume or ability but hope I made up for it in prolific posting and enthusiasm) as I can avoid all of this and have no case to answer, it is all suddenly a lot less complicated thank goodness.

R19KET

John,

Thanks.

I totally agree.

I believe in "competition", it's how we learn, and progress. Subaru tuning has come on massively in the last year or so, IMO, mainly due to a few individuals pushing the limits, to the benefit of all.

I would be great if everyone was allowed to just get on with doing their own thing. One day maybe.

Mark.

AlanG

John and Mark

Agree with what's been said, especially on John's sentiments.

I'm putting myself out on a limb here and expect to be flamed for saying it, but i think (and this is where the flame bit comes in) the whole issue surrounding the development of the marque has been down to individuals interpretation of what are deemed to be the most suitable components to further the limits of the Subaru engine.

There has been so many posts on the subject which ultimately ends in a feeling of rivalry between individuals because they cannot admit to being in the wrong or alternatively cannot admit to there being an alternative method of achieving the desired result.

If this thread develops further from these posts, then maybe it will clear the air, but to all those concerned, (you know who you are) admit where you failed to inform customers/owners of your lack of knowledge on what needs to be done to an individuals car to allow them to achieve their goal.

It takes a brave man to admit that he doesn't know everything there is to know about how to tune a Subaru, but in my opinion i respect those that admit they don't know, if the circumstances dictate what is required is out of the ordinary. Unfortunately, too many people wish it to be known that they have the ultimate in knowledge of the car and are to be seen as some form of Guru and nobody else should be consulted as wrong information will be given to the Subaru owner.

I can see why this happens though, cause dealers with knowledge of their product wish customers to come back time and again and must be frustrating when the box shifters are in competition to them. This is not a dig at box shifters. At the end of the day, you have to make a buck and i myself am only too willing to phone around and get the best deal (human nature after all).
What does annoy me is exclusivity, whereby only one dealer can sell you a component and basically dictates the price, in other words inflated in the knowledge it can't be purchased elsewhere. I firmly believe competition can be healthy for all. Customer has the choice and retailers have their margins they can work to. If that retailer can see the bigger picture and basically gamble on the customer coming back for repeat busines on other items, then a profitable company ensues.
I can see why dealers do this though as it guarantees that customers have to go to them for these parts, but it's a bit like being cheated cause you don't have the choice of who you want to do the deal with.

For example, i work in the brewing industry so you can bet your bottom dollar i can get booze chaeper than the majority of you. Fine in itself until christmas for example, when the larger supermarkets battle it out between each other to get customers in and basically sell cases of lager cheaper than they buy it for, purely to get the customer through the door. The customer then thinks this place is dirt cheap and doesn't think too much about the cost of other items, assuming the retailer has priced everything else in the same light.

{Edited to take out names of specific companies and attempt to clarify my thoughts without people assuming i'm having a dig at them!!}

Alan

[Edited by AlanG - 9/9/2003 2:02:07 AM]

harvey

iTrader: (48)

David : Stevie is right. No such thing as enough, whether it be speed, bhp, torque, spool, mpg or birds (on the grouse moor).
Good luck with the mapping.

Rannoch : If stripping JB`s engine, finding no piston or valve damage and nothing other than consumables are required, takes well over two months, then obviously your engine could be quite a long way off. Can I ask you again, what is your intended bore, stroke, compression ratio and any details of the lift and duration for your STi V cams? These things are of genuine interest to many and particularly to me because of the stage I am at with my CDB. Also do you know the intended deck height?
In answer to your question I decided to proceed with the CDB 2 litre engine at the end of May as you have seen on my web site. The 2.2 block was sleeved and all parts sorted to bring it to short engine stage, where it was at mid July. I then robbed a cylinder head as you know and when a second hand unit was not available I eventually purchased a new one which I have just received. By coincidence, earlier today I have also sorted out valves and springs. So we will go forward again.
I am in no hurry for the engine as the current open deck 450bhp unit performs well and we have found more bottom end torque. While I thought development on this engine was complete I now want to experiment a little further so I need to stay with it for a bit longer even if the other engine was already complete.
My arrangement with Matt Clark is that he works on my engine when he has nothing else pressing and that is not very often. This keeps the cost down for me and as a Scot, this is important!!!
With the original engine, which I needed urgently, I had never met Matt Clark before, but I took him a boot load of junk on a Tuesday morning and collected the short engine that Friday with Arrow Rods, Cossie Pistons, uprated oil pump, etc. etc.

John : Thank you for your kind words. Glad you feel a weight has been lifted from your shoulders. Also that your engine is in and sorted soon.

Alan : You have certainly hit the nail on the head with certain suppliers trying to corner the market with exclusive product lines.
I hope you do not think I profess to know all about Scoobys because I most certainly do not and I benefit greatly from being able to pick the brains of those who know far more than me especially in their particular specialist areas and assessing the information I pick up. In the process of increasing my knowledge I am indebted to Bob Rawle who I have been able to lean on quite heavily on a regular basis, John Pye, Matt Clark, Jack at Ion, with lots of help from Andy, Jonny Gav, and yourself. Listening to intelligent diverse views helps stimulate the process of discovery. There has also been lots of reading material, some of which has been totally over my head but `Forced Induction Performance Tuning` by A.Graham Bell was very interesting.

You got the new turbo fitted yet?

StanS

iTrader: (3)

Totally agree with JB. So many top blokes.
Mark has given hours of patient advice and explanation, supplied many parts, and given exceptional back-up/remedial service when I had a (typically for me) one off manufacturing fault.
Harvey has shared his knowledge as to what worked for him (some of which I have copied!!) and is aways ready to give helpful advice.
Andy F supplied a turbo which did exactly what it said on the box, suited my power band and gives MASSIVE grin factor.

Without the help, advice and time given by most contributors on this thread and loads of others over the years, my knowledge and progress in achieving my relatively modest goals would be considerably worse - so thanks .

Long may the helpful and positive posts/attitude continue.


My 2p worth.
Stan

David_Wallis

Harvey,

Maybe I've grown up, maybe I've grown bored.. I dunno.. its just not as it was

ustolemyname??stevieturbo

iTrader: (1)

Get driving the car David.

AlanG

Harvey

Have fitted a 20G 05/06 to the car and as of today is up and running at a maximum of a bar of boost. There is another school of thought which i'm trying just now to see the effect of the changes, hence the low boost.

Thanks go to Andy for building it at very short notice after explaining my needs to get the car on the road in as little time as possible.

I also have a replacement rebuilt/balanced TMI-141S turbo still in it's box. All credit to Mark and Turbo Dynamics for a very quick turnaround after an untimely failure. Thursday pickup of failed unit to Tuesday rebuilt unit is very impressive. Thanks.

I also fitted a replacement aeroquip oil feed pipe since although i have had no direct feedback on the last of the previous two turbo failures, word received secondhand has been given back to me suggesting that the car is the problem and not the build, so am taking no liberties with anything to do with the car.

At the last failure, I went over the car with a fine tooth comb to find out why the turbo failed and to date can see no reason for it being attributed to the car. I have said before and many of you who know me, will back me up when i say this, if the fault had happened due to a failing on my part or my car, then i would have been the first to put my hand up and accept the inherent costs. It's not my nature to skirt round these issues and try to blame someone else.

As it is, my concern just now is "what if another unit fails?"
I cannot take any chances anymore since if continued failures ensue, then sods law will dictate an engine is going to go and no-one will bear the cost of that apart from me.

Stan

Long time no hear, how's things?
Good to have finally met you at TOTB2.

What was the nature of your manufacturing fault?

Alan

AlanG

Harvey
I re-read my post above and fail to see where you are coming from with the above quote.

I have never said you profess to know all about Subarus nor implied it, but what i can say is that since i met you when you first bought your Scooby, you knew very little about the marque, but have listened and spoken to a great number of people and taken on board the advice they have given you, so much so that your learning curve went vertical! and have soaked up a lot of information relating to Subaru tuning like a sponge and have been more than helpful in passing on this learned knowledge to others including myself as and when the need arose.

That, to me, is what the Subaru community e.g. Scoobynet should be about.

Alan

R19KET

Alan,

I'm a little confused. With the first turbo, it was inspected, and found that the thrust bearing had failed. Some internal parts had gone "blue" due to excessive heat, indicating a lack of oil. The inspection showed no visable reason why this would have occured.

However, when we discussed this, I said that I didn't believe it was car related either. The turbo had been run for several months, so anything "fitting" related could be discounted. That's besides knowing how meticulous you are.

With regards to the second turbo, it appears that the compressor wheel has jammed on the cover. Whilst we thought the nut had a "left hand thread", it doesn't, and this is how the nut came undone.

The nut caused too much damage to identify why this happened, but the thrust bearing was fine, so the wheel to cover contact wasn't due to that.

The bottom line is that in both cases, the problem couldn't be clearly identified, but the turbo's were replaced under warranty without question.

Mark.

harvey

iTrader: (48)

Alan: At a guess you have had about seven turbos with component changes etc. All from Mark. Two have failed terminally. Now you have a turbo from Andy. If it runs for 80 miles it will have done better than the last one. Run it for 2k mls,get a rolling road figure and put your findings on here.

Cheers. Good or bad we will all learn something.

Adam M

Harvey,

I don't think that last post was exactly in the spirit of finally getting this fued over and done with.

Things are never so black and white, and there really was no call for you to summarise in such as way as to disparage Mark.

As has been said time and time again, can't we all just get on with our own things now, such bickering is tiresome.

AlanG

Mark

As i say in the above post, i'm very impressed with the way in which you and Turbo Dynamics have dealt with the last failure, as you have always done with previous items and i have publicly written on this board in the past with regard to your aftersales service which is second to none. I am NOT having a go at you!

It has been intimated to me by a third party that when the TMI-141S failed and was sent back, due to Turbo Dynamics low warranty returns, it "raised eyebrows". For a second one to fail (especially in such a short period of time), it would intimate there was a problem with the car. That's what i was told.

Now. rightly or wrongly, it may be a mistake on my part to be listening to a third party who had spoken to Turbo Dynamics when the topic of my car came up, but at that point in time i had nothing else to go on.

Irrespective of this, the main issue here is why the turbo failed.

As you know, i ran the car for several weekends with no issues to my knowledge and extremely happy with the cars setup. The problem arose when changing the compressor cover for a different inlet. I was just as shocked as you were to learn that the blades had been rubbing off the compressor cover, since there were no untoward noises from the car or change in performance. Perhaps, this is where the "blue" internal parts came about because of the continual rubbing?
The thrust bearing did fail. That we are in no doubt. The question is "what caused the failure"

Could it have been a bad build? Unlikely.
Could it have been incorrect wheel/cover clearances? Again, unlikely if you take into account Turbo Dynamics experience in building turbos.
Could it have been just unlucky? Most likely.

With the replacement though, this is not so clear cut.
I built that car back up checking and double checking everything possible before running the car cause i didn't want to continually change turbos. Yes, i have said to you in the past i don't mind changing them (during development stage) but nevertheless it is a tiresome thing to do when it has to be done due to component failure. There is motivation in doing work if there is a reward at the end of it but to do work because the same job is failing, you tend to get a bit down.

As spoken on the phone with you when it failed, both you and I were dispondant at it happening. My concern though was why it happened and i did say to you if it is found to be car / me related, then i would accept responsibility.

On removing the turbo i checked related components to the turbo i.e. water supply and return and oil supply and return along with the exhaust manifolds.

I found nothing with the water side, nothing on the oil side and nothing with the exhaust manifolds.
Specifically with the oil side as this seems most probable cause i.e. lack of oil, i cranked the car over to check for supply (after turbo off) and there was a healthy flow. Removal of the pipework didn't show anything either.
However as a precaution for the replacement turbo, i have changed the std issue pipe which if you look at it, does have a very small bore feedpipe (1mm at either end) and a small hole in the banjo fitting at turbo end. (again only 1mm) with an Aeroquip hose having a larger diameter bore and have also increased the hole size on the banjo bolt and doubled up i.e. two holes.

The whole point to this post is not a dig, seriously. But am raising a concern in the respect that there have been two failures of which i am in no doubt are component failures unrelated to the car. Now there is a possibility there may have been a bad batch of bearings which Turbo Dynamics are using to build them.. I don't know.. or as written earlier perhaps clearances aren't wuite right. Again..I don't know..

The final one is it could be the turbo isn't quite the right spec for my car. Perhaps the turbo is overspeeding if i run 1.5 bar at 7000rpm which could explain the first failure a bit better. Remember, the blades on that turbo were bent outwards Again..I don't know.. i'm no turbo expert.

The problem with this thread and others is the antagonising between what amounts to three people, you, Andy and Harvey. That's it. Nothing else. What has went on in the past dictates how you respond to posts like mine. Harvey asked me a question above and i answered it. I wrote further info on that at the time because replies would have came up asking questions which would have amounted to the same thing.
What is written previously from me is fact. And at the end of the day, it would have came out in the wash.

I have no problem with you Mark, same with Harvey and Andy, but your politics with regard to the situation you're in i am not going to be party to.

Now lets have some constructive discussion on what has happened, no backbiting or browny points needing to be won. If a conclusive outcome can be had, then maybe there will be benefit to others in the future.

Alan

john banks

It is a tricky balance between being the first to try something and possibly hitting on a success, and trying something that is proven but less advantageous. If you are trying something that hasn't been tried before then you will be a crash test dummy, no two ways about it. I am most familiar with pharmaceuticals in terms of approval and quality control.... in this case the regulatory authorities demand an almost unbelievable number of costly rechecks and repeat trial work before a slightly altered product is released. Even changing the sugar coating on a pill needs approval and is costly. The equivalent to this would be cosmetic changes to a turbo, never mind changing a compressor wheel or housing or bearing. I gather that Japanese OEM and aftermarket manufacturers operate a similar quality setup - result is lacklustre performance in the case of the OEM, which we then modify away the safety margins of, and the aftermarket results in high prices - eg HKS turbos.

Must be tricky trying to compete with box shifters and various web suppliers of turbos yet offer innovation on a one off or handful basis, especially if you are aiming for performance. Reliability trials cannot be comprehensive in these circumstances.

Pays yer money etc...

No dig at Mark or Alan here, or anyone in fact

David_Wallis

cant offer much here.. but I was under the impression that if you over speed the turbo the tips go supersonic and break off??

David

R19KET

Alan,

I was unaware of the 3rd party input, and just wanted to confirm things to the best of my knowlege.

The situation with yourself is frustrating, because I've not had a problem with anyone else.

I have no interest in "politics". However, some people want to cause as much conflict as they can. I don't want to get involved, but when incorrect, or misleading information is posted about the products, or services I provide, it needs to be addressed.

I am GENUINELY happy that Andy supplies turbo's. Believe it or not, I even recommend certain people speak to him !!!

Mark.

AlanG

Mark
I appreciate what you are saying, this is why i'm trying to ensure complete clarity with my situation. It may also flag up a potential problem for your other customers using this unit if there was indeed a problem for example, of a faulty batch of bearings. I don't know..
But remember, the first unit ran fine. It wasn't until i took the cover off when a problem was found. Worthwhile trying to get feedback from others using it if it's possible for them to check?

One reason for my concern is that there may be an issue with using the TMI-141S which we don't know about yet. After all, it's still early days.
As you know the original spec was 1.5 bar to 7000rpm. To date, this has been used at a maximum (at any point) of 1.4 bar to 7000rpm. Is it possible it could be overspeeding to achieve the pressure/volume at 7000rpm?

Also Mark, you don't have to convince me of your intentions on this board. As a customer of yours i cannot fault your willingness to help rectify any issues with any purchases i have made from you.

David

The odd thing with the first TMI-141S turbo (apart from the thrust bearing) was that there were two or three blades bent outwards. if something had been ingested, the blades would have bent in and also there would be scoring of the housing but in this instance, the blades had bent outwards and no marks on the cover at that area.

Alan

R19KET

Alan,

After the bearing failed on your turbo, and we couldn't identify why, I actually recalled several 141's for inspection.

So far, ALL of the thrust bearings have been in PERFECT condition.

I have another that has just been returned, and it also has no linear play in the shaft at all.

So whilst we've been unlucky with a one bearing, it would appear that a batch problem can be discounted.

It's very odd that some blades have bent outwards. The Garrett wheel is very strong, to the point where even where they have hit the cover, they didn't break. I don't believe it could be caused from over speeding either.

Mark.