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opticaltrigger

[race_prep] Turbo Hill Climb Project

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opticaltrigger

Hi everyone I'm new to the site and this is my first post but I thought I'd mention some of the development work we have been doing on the motor for our 205 gti turbo hill climber / drag racer and look forward to any comments any of you guys may have.

The project is about a year old now and came about as a result of noisey valve shims.The car had been off to a so called expert at a local garage who promised the usual stuff,you know - 42000 bhp @ twelve rpm rising steadily all the way to 12 grand.All that actualy came back was a car that was noisey and slower with a big bill.

I had a good long look and think and decided the thing to do was to start again but this time with a plan.So my mate and I (the owner),(I'm just the wrench by the way) thought hill climbing and a bit of drag racing sounded fun and I've got a bit of drag racing practice under my belt anyway.

From the outset we both decided that we would try to incorporate some forward thinking ideas into it,so I got on with planing the power plant and my mate took up the rains on the chassis.

The motor is a 205gti 1.9 unit,the c.r. has been droped to 7.95:1 using a combination of chamber reworking and a decompresion plate of 1mm thick,the bottom end is as stock with the adition of new rod bolts,ballancing,oil pump drive,blah blah blah.The reason for keeping it stock down there is because its so Tonka to start with.

After finishing the chamber work I set to with the inlet and exhaust ports giving the exhausts a more 'D' shape to speed up the gas flow round the bottom of the port,the inlets have had basicaly a straightening and enlargment idea.There's a cam installed and three angle job on the valve seats,although I've widened the contact face on the exhausts a little more than normal to aid in heat dissipation.The turbo is to be set at 15psi.

The ignition system is my baby realy.I didnt want to just buy the usual maped ecu because its to easy,boring,and limiting as your soley relient on somone else's ideas of what windows of operation your motor would like.Sure your gona get a good bit of kit that works but what have you learned-Nothing!!!.So I took a bunch of micrcontrollers and some other bits and bobs ad started building one.I wanted a system that would fire the coils sequentialy in the firing order allowing me to run one coil per plug giving me the opportunity for large plug gaps.The system is being equiped with a multiple spark discharge circuit and ignition timing with feedback from a boost sensor.

From the outset I wanted to use optical sensors so the rotor arm has been removed to make way for an optical interuptor wheel to trigger the optical sensors which ultimatley fire the coils.I have to say the code that I've writen for the project has been chalenging and although the firing sequence part is up and runing and the multiple discharge section is ok,the timing section is much more complex but I love it and its well underway.

Anyway enough babeling from me here's some pics.

 

Ok like I said new here.How do I get my pics on anyone help,I'm gona need it.

Cheers

O.T.

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number2301

Just below where you post (on the full posting screen not the quick reply one) there should be an option to upload a file. However as you're new that might not be there so go to www.photobucket.com, sign up and upload your pictures to there. That will then give you a link to post it on here.

 

That's an interesting approach to engine management you've got going on, have you looked at the Megasquirt stuff?

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Batfink

thats really low compression! Would higher not have been better for hillclimb? I guess if you are off boost your run is buggered so maybe not...

Edited by Batfink

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opticaltrigger
Just below where you post (on the full posting screen not the quick reply one) there should be an option to upload a file. However as you're new that might not be there so go to www.photobucket.com, sign up and upload your pictures to there. That will then give you a link to post it on here.

 

That's an interesting approach to engine management you've got going on, have you looked at the Megasquirt stuff?

 

Hi Number2301,Thanks for the reply.

I havent had any hands on dealings with the Megasquirt equipment although I've done some research and have a fair understanding of its operation.

I guess I've gone about it this way more as a personal challenge as I have an interest in electronics as well as being a dedicated petrol head.Plus as an added bonus the learning curve has been great.I've never realy considered the ECU to be much more than a filing cabinet full of different ideas on how to run an engine.

Thanks for the pics tip I think its gona be a photo bucket job as thiss site does seem to be very hiarachy dependent on what you can and cant access.I tried to go into the section for projects first but denied.Still just glad to get on the forum it took ages to get this far.

Thanks again O.T.

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jackherer
I tried to go into the section for projects first but denied.Still just glad to get on the forum it took ages to get this far.

 

Its nothing personal :lol: Nobody can post in the projects section, selected threads are moved there, this one is definitely a likely candidate once its got some more info/pics.

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Galifrey

Open a photobucket account, post pics there, use the code to link in your posts.

 

That is the BEST way.

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opticaltrigger
thats really low compression! Would higher not have been better for hillclimb? I guess if you are off boost your run is buggered so maybe not...

 

Hi Batfink,thanks for the comment.

I do hear what your saying on the c.r. and in the desighn stage I did strugle over it alot myself but I've desighned the motor with power as a priority and I feel that your right in your concerns over it in so much as loss of torque in the lower end could be an issue.However I went ahead at that as it does give me some degree for movment on my final boost figure and I felt that by perhaps building an ignition curve using the multiple sparks runing say 20 degrees over TDC I would be able to go some way towards offseting the off boost lower end torque issues.But the next few months will tell once we get some dyno time to do some proper measurments.

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opticaltrigger

Hopfully some pics if I did it right.

 

XU9JAENGINEBUILDUP003.jpg

 

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Galifrey
SD530506.jpg

 

Nitro model engine cylinder head from a car as an optical trigger I think?

 

Ingenious

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opticaltrigger
Nitro model engine cylinder head from a car as an optical trigger I think?

 

Ingenious

 

Exactly that.It hapened to be that the spacings in it gave me a buitifully machined bit of kit with a real nice amount of dwell to give the program plenty of time to do the calculations.

Whats interersting to see is when you run it up and conect a scope it you can see the machining tollerences in the form of time.Well its interesting if your into it I guess.

Thanks though.

O.T.

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tony perks

Why the d square form on the exhaust ports the round ports flow very well opened out to the gasket lines?

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Tom Fenton

Hi there, interesting project, I finished my turbo conversion of an NA based XU engine earlier this year, I started with a 1600 as I like the revvy nature of the short stroke. In any case I managed 195 bhp.

All the optical sensor stuff looks interesting, although dare I say it overcomplicated and perhaps prone to dirt ingress? In any case if that floats your boat then go for it. I used a DTA standalone ECU, and begged the use of a rolling road and set it up myself, I am also a person who likes to "do it myself". I used the Mi16 flywheel with inbuilt trigger pattern and the Mi16 crank sensor, this has all been ultra reliable with no issues.

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opticaltrigger

Hi Tony,

Firstly the reaon for the 'D' form on the exhaust is because during flow bench testing in a previous life I found that in almost every case without exception a flow increase across the board was to be had by flatening out the bottom of a swept 90 degree (or less) port.The reasoning behind it being that gas will allways travel faster round the top side which has a much less agressive profile in comparison to the relativley harsh turn at the bottom.Therefore by flatening the lower side and lessening the severity of the turn a greater surface area is created and the gas speed and flow in that zone is increased.It dosent completley rectify the problem but it does put a large hit into it.

Being as I'm using a turbo there is also the benefit that the gas flow of exhaust from the cylinder to the turbine spends less time traversing the port and dumps less of its heat energy into the cooling system.A very large proportion of heat energy is lost in the port especialy in the area of that hard turn at the bottom of the port and imideatley opposite on the opposing high side.Thermal losses in the pipe work are quite managable with modern coatings etc but the port requires a little more attention.Anyway thanks for the question,hope my answer helps.

All the best

O.T.

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Galifrey

You deleted all the pics?

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opticaltrigger

Hi Tom,

Yes dirt ingress could prove to be an issue indeed but I feel it's only going to be an engineering issue to overcome if it does prove to be so.But having said that I cant completely dissagree with you Tom and I do have the feeling that no matter what methods I employ to keep dirt at bay it's going to be of concern.However the response time delivered by optical sensors is unbeatable especialy when compared to say magnetic / Hall etc so I do kind of forgive myself for using them at least a little when I remind myself that its main function is as a race car.

By the way I would love to see some specs and pics on the 1.6 if pos,sounds like a great project Tom.

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opticaltrigger
You deleted all the pics?

 

Yes sorry bout that I'll go get em again.Was trying to load some chassis pics and balls'ed it up.

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Tom Fenton

Hi, there is the build thread for my engine in the "Members Works" section of the forum, its 40-odd pages though so you will need at a guess at least 3 pots of tea to read all the way! Hopefully you will find it interesting anyhow, the mods I made to the block for undercrown oil cooling may be of interest to you.

I only say about dirt on the sensors as I know the 8v dizzy are prone to getting oily deposits through into the cap. But as you say conquer and overcome. Good luck with your project.

 

Link to my thread- http://forum.205gtidrivers.com/index.php?showtopic=87784

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DrSarty

Ref dirt ingress, you could try an OE Pug part.

 

capturefu.jpg

 

Interesting stuff dude.

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opticaltrigger
Hi, there is the build thread for my engine in the "Members Works" section of the forum, its 40-odd pages though so you will need at a guess at least 3 pots of tea to read all the way! Hopefully you will find it interesting anyhow, the mods I made to the block for undercrown oil cooling may be of interest to you.

I only say about dirt on the sensors as I know the 8v dizzy are prone to getting oily deposits through into the cap. But as you say conquer and overcome. Good luck with your project.

 

Link to my thread- http://forum.205gtidrivers.com/index.php?showtopic=87784

 

Briliant Tom realy nice work,

I thought the piston cooler jets were a nice touch,drilled into the block like that. Did you find any probs in the way of either oil pressure drop or oil passing the control ring?

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opticaltrigger
Ref dirt ingress, you could try an OE Pug part.

 

capturefu.jpg

 

Interesting stuff dude.

 

Thanks very much Sarty,nice tip.It's certainly got to help with the matter.Although to be honest I think the dizzy cap might have to be completley made again from scratch as I dont think theres gona be a great deal of it left by the time I do the nesecary clearencing.

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opticaltrigger

Anyway for anyone that wants to have a look - some chassis / body pics so far.

I've put them in a rough order of progresion.

 

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Image000.jpg

Edited by opticaltrigger

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Tom Fenton
Briliant Tom realy nice work,

I thought the piston cooler jets were a nice touch,drilled into the block like that. Did you find any probs in the way of either oil pressure drop or oil passing the control ring?

 

With hot oil and idle revs then it does drop down as you'd expect due to increased area for oil to flow through instead of building up pressure. One thing I will do if it ever comes to bits again is alter the oil pump drive gear arrangement to speed up the pump speed a little compared to crank speed, this is easily done using XU10 (2.0) oil pump parts as opposed to the standard XU5 & XU9 parts; when you rev it up a little from idle the pressure quickly builds. Having said all this I've done 4000 miles now of reasonably hard use and no problems.

I've not noticed any problems with oil control, I obviously fitted new rings and had the liners honed, but it doesn't use oil, and doesn't smoke either.

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opticaltrigger

Sounds like it's ticked all the boxes Tom,great stuff.

I asked about the oil ring because its been a mod thats kicking around in the back of my head for a while now and I figured that the ring should be able to cope but it's great to hear from first hand experience.Theory can only get you so far.

 

Ive been toying with idea of a secondary pump Tom either electrical or mechanical to do the turbo oiling so I guess it could also be incorporated into the squirters.But that lovely bit of work with the drillings that you've done realy is exquisite I think and now I've seen it there is part of me wants to run up to the workshop and tear it all to bits and get drilling.

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Tom Fenton

I don't know about exquisite, seems to work though! Bear in mind the XU10 turbo motors have oil jets and a turbo to feed as standard, so perhaps an extra oil pump is just un needed complication. Also the XU10 turbos cope OK with the oil jets, and use the same style oil control rings as I have used too.

Obviously in a competition car the more simple things are, then there is less to go wrong which can be the difference between a win and a retirement.

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opticaltrigger

Well I've finaly come out of the workshop and can say the motors as good as finished.At least the hardware is,the software is still in progress at its own pace (when I'm in the mood realy),although now the motors as good as done I can apply a bit more time to it.

Have had a mad time of it with the dealer,trying to get a replacment spray bar for the camshaft.I placed an order for one in mid August and was told it had to come from France.On Monday they called to tell me it was'nt in France but here all along.Still,got it in hand now and should be with me in a few days.

Next on the cards is the differential to go in,again in a few days when the bearings get to me, (I've got to ask a question in the mods section about that if anyone could help me with some addvise as I've never done one of these boxes) and then it can all go back in the chasiss again.

The bodyshell has moved on slowly awell and the alluminium for the inner door panels has just been done and the inside is almost looking like it might see some paint in a short while to.I'll post up some body pictures as soon as I think to get there with a cammera and take somore.

Anyway just a couple of pics of the motor in it's latest state and as soon as I'm a bit happier about the software after somore testing I'll put some of that up for those that are that way inclined.

 

All the best

O.T.

 

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Edited by opticaltrigger

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