Lotus 23 project

For keeping us up dated on your building of a Clubbie/Seven replica

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This section of where you guys can show off the progress you make as your build comes together of your clubman, give details of any modification progress, share pictures etc. There are just a few rules that need to be followed for this forum to stay nice, clean and easy to use:

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Cheers Stephen

Re: Lotus 23 project

Postby steveb » Wed Jan 04, 2017 9:57 am

hi Patrick, An off topic question.
Your previous seven, what chassis design is it?
i have put the question to talkiet, and he suggested to ask you.
Your new intake looks great, it's good to see people making parts,
too many skills are disappearing from "engineering"
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Re: Lotus 23 project

Postby bzrse7en » Wed Jan 04, 2017 1:40 pm

steveb wrote:hi Patrick, An off topic question.
Your previous seven, what chassis design is it?
i have put the question to talkiet, and he suggested to ask you.
Your new intake looks great, it's good to see people making parts,
too many skills are disappearing from "engineering"

Hey Steve, maybe nobody has said, but there is a discussion section for build diaries. The moderators used to be really hot about keeping things in the right place and dished out quite a few telling offs. Have moved us over there....
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Re: Lotus 23 project

Postby bzrse7en » Sun Jan 22, 2017 9:29 pm

Here's the manifold in place.
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After fitting it, the engine notcably ran a little leaner on low throttle settings. It is about 15mm lower than the original and so will help in my future plans of ditching that bonet scoop.

I have a TFSI K03 turbo
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Was cheap-ish before freight was added from Aucland.
Was described as having no play - but that was not entirly correct.

The hot side turbine wheel is identical to the one I already have, but the compressor is about 5mm larger as is the cold side housing. It is said to be able to deliver up to 280hp on the 1.8T with boost up to redline, I think that figure is more than ample as I don't have that now. It isn't a bolt on job, the manifold ports are the same, but the stud placing is different as is the exhaust flange. So some dicking around is necessary.
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Problem is, now that I have it, it seems it might not fit :cry: . the outlet flange is quite large and might hit the top chassis tube - bugger. The only way i'll know is to take the other manifold off and offer it up. It might have been easier and maybe cheaper if I'd just bought that K04-015 from Aliexpress in the first place :roll: .
I have a plan if it won't fit. Knowing the turbine is the same on both turbos and they share many common parts, I will add the new larger cold side onto the original hotside, making a hybrid.

Here is a screen shot of a log done recently, second shot close in. You can see the boost (MAP in red top graph) drop away as the revs rise (white), with max MAP pressure around 5000rpm, but the boost duty (white lower graph) is increasing. Admitedly I only have 60% boost duty set at present, but at 7000 rpm it is basicly only pushing 5psi boost.
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Re: Lotus 23 project

Postby steveb » Mon Jan 23, 2017 1:49 pm

hi Patrick. Good to see progress being made!
Well the old compressor wheel is knackered, i have in the past mixed turbos, mainly just swapping the exhaust housing for a smaller one with good gains, or you could read it as fitting a larger turbo on a standard housing.
I haven't had any experience with one piece exhaust manifold as the Audi has, i have always had to make manifolds using schedule 40 type bends. not being familiar with the 'VAG" engines, are there any options with separate exhaust housings similar to a T28?
Question #2. can you fit a second air temp sensor with the mega squirt? one at inlet manifold and one at air filter, to give an idea of how the intercooler is performing. i forget what the air temp is safe to run at, before the pistons go soft. Subaru had a case of engines melting on 40 deg C days, even with a 100% efficient intercooler, that would still be 40 deg C.
Can you fatten up the mixture at high inlet temps and back the timing off in relation to inlet temps on mega squirt? i.e safety tune... how bigg is your intercooler?
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Re: Lotus 23 project

Postby bzrse7en » Mon Jan 23, 2017 3:38 pm

Yea, you can see it's been rubbing in the housing, that's why that turbo is in pieces.
I can get t28 manifolds no worries, but space is limited to some degree width wise and don't want to buy a whole lot of stuff and find it then dosn't fit. A custom steam pipe mani is a solution however. The turbo I have fitted currently has a seperate manifold, the TFSI one is a one piece. It's pretty smooth inside and is reputed to be a step up in design over older designs. Even thou I said it will be a bit of dicking around to fit it, it is far easier than building a new manifold and all of the oil and coolant lines. All the coolant and oil lines on the tfsi turbo are as close as identical to the standard turbo.
In megasquirt I can change pretty much anything I like, and could add another MAT sensor. There is an air temp mixture correction table. MAT after intercooler went up to 45.9C. I think the small turbo might accentuate MATs as at 6-7000 rpm it isn't efficient, you can see it is tailing off after 5000rpm. The intercooler is fairly small, it's an alloy MR2 unit, but I doubt this thing is mking any more than 180hp. It is feasable the intake is picking up hot air from engine bay and I need to look into that. In part, this is why I want to remove the bonet scoop, the inlet has been blocked to stop passangers getting heated when you stop, but it then dosn't get airflow thru the engine bay. I want a rear facing scoopy thing to draw air out, so fresh air comes in thru the wheel arches.
I am more concerned with the duty cycle going over 100% currently, might need bigger injectors.
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Re: Lotus 23 project

Postby steveb » Mon Jan 23, 2017 6:18 pm

hi,
The 23 keeps evolving... this is good.

steveb
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Re: Lotus 23 project

Postby bzrse7en » Mon Apr 17, 2017 7:29 pm

Finally I am feeling satisfied with engine performance. The std turbo peeked out at 4200rpm and dropped right off after this, down to 5psi at 7000rpm. This actually made it un-fun to drive.
I was going to fit a turbo from a VW TFSI (GTI golf) which promised an optomistic 280hp - it didn't fit in the chassis. So I have made a hybrid turbo from both the turbos. Looking at the TFSI hot side, it's turbine is the same as 1.8t, as is most of it's housing. The wastegate port was a bit different and I was able to modify it to resemble the TFSI's as well as give it a port. The cold side wheel is bigger by 6mm as is the housing. All other parts are interchangable. Because the whole rotating assembly was swapped across, it didn't need balancing. The blow off / recirculation valve is integral with the housing and this came from an Astra turbo (the TFSI valve is electronic, so couldn't use it).
It now peeks at 5000rpm and holds 12psi at 7000rpm. At 5000rpm I did see 25psi but have pulled back boost to 18psi currently - which is still pretty high.
It now pulls very well and is more progressive - or slower building boost.
Have also fitted an adjustable fuel pressure reg and raised pressure to 4 bar and fitted 315cc (at 3 bar) injectors from a volvo instead of the 210cc originals. I now see 81% max injector duty cycle not the 120% a while ago. Also have moved the airfilter lower and away from turbo. Manifold air temp was between 40 to 50c, now it's 25 to 51c. So the baseline temp is lower, and assume the same higher peek temp is because we are now making more boost. It is now pretty quick but I can't see it making 280hp, maybe 220hp judged from the seat of my pants.
It's now back to retuning the fuel maps, cold start, accel enrichment etc.. as it's all now different.
Now of concern is the oil usage :? the newly installed catch can fills pretty quick. The breather is in the side of the block, so am hoping the issue isn't blow by, but because of the non standard windage tray has changed the oil mist dynamics in the crankcase. I can try a vented cam cover off a differnt model Audi.

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Re: Lotus 23 project

Postby steveb » Sun Apr 23, 2017 12:43 pm

hey good to see the 23 back in action. at least you are moving forward. (some of us are going backwards, yet another restart).
Have you done a recent compression test? (broken piston land, hope not) how much ignition timming (adavnce btdc) is the ecu commanding at what boost rpm etc.
i have done a recent oil change on my weekend driver, change from semi synth to dirty old gtx, because it was there, (turbo rated etc) and are getting blow by into turbo inlet, smells on startup but no smoke,
nothing else has been changed re ecu settings. will change back to semi synth. it's use by date might be up for a rebuild.
Steveb
P.S you have a very cool little car, thanks for showing it.
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Re: Lotus 23 project

Postby bzrse7en » Sun Apr 23, 2017 9:54 pm

No, haven't done a comp test recently - hopeing not to, if you know what I mean, but it might be time. At this stage I am hoping it has something to do with the breather system, which, I have changed. I changed it because it was a convoluted $hit plastic contraption and prone to failure. Possibly the convoluted feature seperated the oil. I copied an aftermarket design, which appears to work for others. Timing table goes down to 5 deg of advance at full boost, AFRs are not lean at full boost either (around 11.5 - 12:1) and I have boost cut set to protect engine - still, I might have killed it.

Edit: Compression test shows 160 - 170 across the cylinders, so it isn't that. Thou it isn't a big surprise as was running pretty well and not fumeing.
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Re: Lotus 23 project

Postby steveb » Mon Apr 24, 2017 4:00 pm

do you have any pic's of your oil air separator, doe's it return oil to the sump?
looking to make up one. David Visard did an article many years on a system called evacu-sump or something similar,
used negative pressure created by exhaust with a long tube into the exhaust to e-vac the sump pressure through an oil separator and return to sump.
I wasn't brave enough to try it... gave up on mini's
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