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70Turbobugīs 2 liter turbo
Hi everybody,
Iīd like to share my turbo project here aswell.Of course itīs a german looker! Here are the engine specs: 94x71 - stock crank and stock cylinders - for now. webcam 86a - out of the box with the 108° LC straight cut cam gears Jake Raby parkerized lifters Cromoly pushrods CR 8:1 stock CU Bus pistons oil squirters for the pistons stock rods balanced with Raceware bolts cryoed and coated KS main bearings and cam bearings. Six 13H7 Remmele through bolts Raceware headstuds 1.7 heads ported 41x35 valves exh.valves are sodium filled,Remmele Dual springs Autocraft 2 stage dry sump pump 200mm 3.9kg flywheel - clutch TBD either Remmele (Sachs) dual disc or KEP dual disc. Remmele CF fanhousing 10 blade 911 fan four 45mm Throttlebodies from a BMW 1150GS Motorcycle - all cable operated,no linkage 4 550cc(@3 bar) siemens/Bosch Injectors Bosch LSU 4.2 wideband lambda Bosch narrowband lambda MFT EGT sensor Bosch IAT sensor Bosch COP igntion modules Ebel-Tec ECU w/boost control Walbro inline pump GT3071R .63 A/R turbine .50 A/R compressor Tial 38mm WG Greddy Blow off liquid-Air intercooler The car: ī84 mex body on a ī70 automatic pan 944 turbo aluminum trailing arms Remmele uni-ball coil over rear suspension 4 piston boxster calipers + discs rear,911 carrera 4 piston calipers and discs in front Remmele uni-ball coil over suspension in front Heigo aluminum rollcage 091 gearbox 944 turbo axles and cv joints 17" cup 1 wheels 205/40/17 + 245/40/17 here are some pics,more to follow Last edited by 70Turbobug; October 19th 2009 at 04:46. |
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Here are a few more:
Iīll take some mor pictures as I go along.These pics are a little old. |
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Hi 70Turbobug and welcome.
That spec has the makings of a very quick motor. I note you are going with a Uniball rear suspension and coilover. Why are you getting rid of the torsion bars, are you intending to race the machine? If you do get rid of the torsion bars then you will certainly need a Kafer Cup Brace - 5 bar type to brace up the rear and accept all the suspension loads you are going to put through the top mount. I see you are going to use an alloy rollcage that will preclude the car being used in most forms of motorsport. It would be better to fit a chrome moly one welded in situ. Its a shame you are not using the McPherson strut front end to make best use of what is a very high spec. Clive |
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Hi Mark,
I knew most of it already, but can't still figure out why you are going to use stock cast pistons in an engine with otherwise such hi-spec and hi-cost components? You can just easily use a $200,- set of Mahle type 1 pistons, which are sort-of forged and very light weight too. They are twice as good and cost near nothing wrt this project. and don't give me crap about the 'compression ratio' with the flat tops Greets, Wally |
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Mark,
What is the 3rd pic in your first set of pictures of ? I see 5 ports in the box, is this to equalize the MAP signal from the TB's ? I noticed the Remmele front uniball suspension setup ... do you have a pic of that ? Thanks Sandeep |
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Quote:
Alex
__________________
1970 Bug 2110cc. ???Whp, ???Ft/Lbs |
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Thanks guys!
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Here is a pic of the coil on plug ignition modules I will be using.They put out 100 mJ.Here is some more info on them:
http://www.bosch-motorsport.de/conte.../html/2847.htm |
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Quote:
You main enemy in a turbo engine is knock. Period. You really don't have the heads/headflow to worry about rpm.. (sorry) The heat retention/conductivity differences of cast and forged alu is really futile in engine operation circumstances. Knock is your enemy and you WILL encouter it sometime during tuning. Then you have either forged ring lands or cast ring lands... Thats my main point |
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Quote:
Porsche ran their '70s 934s and 935s with uniball/coilovers not because the torsion bars were deficient but because it saved weight and it gave them a greater selection of spring rates. Neither of those reasons would apply to your bug. Clive |
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Sounds like you'll have a hell of a motor when it comes together got any plans for the poor 091?
On the piston issue it doesn't make sense cost wise to use a cast piston. Even if you have already built the motor and gone through break in I would still strip it and get forged pistons. Those cheap cast pistons will cost you a fortune when they go, not if, when. It could be just a ring land (new piston and barrel maybe some head work), or maybe the piston crown goes (time for a new head, rod, maybe crank, cam, lifters, possible fire damage). The point is $200 now could save you thousands down the road. I would also stay away from the wiesco pistons for a turbo motor. Even though they are forged the upper ring land is very thin and doesn't hold up the detonation under boost. |
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All the points you guys have made are correct and Iīm not arguing against them per say.There are some people that donīt like the Remmele set up - which is fine.To me,itīs a great set up and it does have a few flaws.If I were to improve the suspension I would build a double wishbone suspension instead.That of course is quite a task and to get it street legal here in germany would cost dearly.The bug will primarily be driven on the street,once in a great while on the track.The Remmele set up has itīs weeknesses of course as does any suspension set up.Whether the loads are transfered into the chassis better than the tosion bars,I canīt really say.But it makes a world of difference compared the usual Koni and adjustable beam set up.The car acts completely different and to me, seems more stable especially in fast and bumpy corners.Another reason is the adjustability as mentioned.
Back to the cast pistons: Yes,you all are right! One big reason for knock is high piston crown temperature and chamber temperature,correct? A cast piston will have less temperature overall.Interestingly Corky Bell explains in his "Maximum Boost" Book the advantages of a cast piston vs. a forged piston.Of course there comes a point where the forged piston is needed due to itīs higher density.I may have to switch to forged pistons for that matter.I would like to keep the 24mm wrist pin because the rods are finished. |
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[QUOTE=70Turbobug;71995]All the points you guys have made are correct and Iīm not arguing against them per say.There are some people that donīt like the Remmele set up - which is fine.To me,itīs a great set up and it does have a few flaws.If I were to improve the suspension I would build a double wishbone suspension instead.That of course is quite a task and to get it street legal here in germany would cost dearly.The bug will primarily be driven on the street,once in a great while on the track.The Remmele set up has itīs weeknesses of course as does any suspension set up.Whether the loads are transfered into the chassis better than the tosion bars,I canīt really say.But it makes a world of difference compared the usual Koni and adjustable beam set up.The car acts completely different and to me, seems more stable especially in fast and bumpy corners.Another reason is the adjustability as mentioned.
.....................QUOTE] We do have advantages in Britain regarding building specials but I was not suggesting a double wishbone unit. In fact, I was suggesting that for the rear you could make life simpler by retaining the torsion bars and adding the coilover to increase the overall wheel rate. I suspect that the reason the Remmelle coilover you have tried works well is that the wheel rate has been increase measurably over stock. I note that Remmelle's rear coilovers are 90kg/cm or 120kg/cm, which is some 50+% over stock. You could achieve that sort of increase by retaining the torsion bars and adding lighter weight coil overs. Whilst Konis have a good reputation I would recommend Bilstein for a performance application and adding a 50lb/inch (9kg/cm) helper + 150ish lb/inch (27kg/cm) main spring. The damper needs to reflect the frequency of the whole spring rate so a notional equivalent would have to be calculated. Clive |
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Ahh now I understand what you are saying.The coil overs I have from Remmele for the rear are IIRC the 2nd generation ones that are made from Bilstein for Remmele.The front unit is the 1st generation model made from Koni for Remmele.The current model suspension is self produced.The good thing with the rear suspension I have is that I am not limited to the springs that are delivered with it.I can choose from various manufactuerers such as KW or other Bilstein springs.I admit you are the first person I have heard to say there is a better option/improvement to the Remmele coil overs using them with torsion bars.They were designed to eliminate the torsion bars.I have heard many pros and cons for the front uni-ball set up.Not everyone likes it.I will see how the car reacts without the torsion bars first.Thanks for the tip!
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Sounds like you have a great project going. I have been thinking of building a turbo engine much like yours down the road (need to finish y 2.4L N/A first) I was thinking of the Web 119 cam. What made you pick the 86A?
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