<blockquote id="quote"><font size="1" face="Century Gothic, Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote"><i>Originally posted by Bobbieslandy</i>
... I'm even prepared to pull the engine out and rebuild it as ..., to be honest i'm not happy with it.
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Rob, I'm sorry to hear that.[:(]
You've got a freshly built, balanced engine, with lightened flywheel. Further work on the bottom end seems unecessary at this stage. Rather, a tuning program that enhances induction and fuel systems seems more appropriate.
Following are the tuning steps I would consider in your position.
STAGE 1
1. Get a compression check done across all pots. This data will be a reference point for all future work on the engine.
2. Improve the induction system by fitting ram tubes/velocity stacks inside your air filters and by providing a cold air feed from in front of the radiator (the original air box makes the latter easier to do, but I'm not sure if ram tubes can be used with it - they would need to be a short length and the filter element may still interfere with the flow characteristics). (Sprintparts suggests that horsepower increases by approximately 1% for every 4 degrees C reduction in inlet temperature.)
3. Renew the fuel system by either replacing the existing mechanical fuel pump (it's still original isn't it?) or by removing and blanking it off and fitting an elec fuel pump, gauge and pressure regulator.
4. Put it on the dyno so you have a baseline measure of its performance. It should be producing somewhere between 127 and 140 bhp, hopefully at the upper range. Use someone with experience of SUs so that you can ensure you have needles that provide the optimum air fuel ratio across the rev range.
I'd address 1 - 3 ahead of the dyno as these will affect which SU needles are best.
<blockquote id="quote"><font size="1" face="Century Gothic, Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote"><i>Originally posted by Bobbieslandy</i>
No no, i won't be rallying it. Well not officially anyway. This will just be just for fun! What sort of ideas do you have with regards to modern techniques?
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It seems Beans, you and I may all have similar ideas in this regard, so based on this, the next stage should be modern throttle body injection with programmable EMU.
I would slowly plan this properly, enjoying the car in Stage 1 tune while accumulating all the necessary parts and then performing the change.
Following is an outline of what I have been considering for my Sprint:
STAGE 2
1. Source a 45 or 48mm DCOE style inlet manifold (they still seem to come up on ebay UK sometimes)
2. Source a good spare head and prep it with:
- matched inlet ports to the DCOE manifold
- polished exhaust ports and combustion chambers
- phosphor bronze valve guides to reduce friction on the valve stem
- bigger inlet valves (space for these is minimal and it's not really necessary in my view)
- 3 angle valve seat job
3. Source and fit fast road (STR091) camshaft and vernier camshaft sprocket; shim to the suggested spec
4. Source DCOE tapered throttle bodies, fuel rails, EFI pump and regulator, airbox and cold air induction piping. (Following sexy pics should keep you salivating) [:)]
5. Source a new EFI fuel tank or good second-hand one and modify it to accept fuel return line and internal swirl pot for fuel pickup
6. Source components to set up engine managment, including
- front crank pulley/damper modified to accept a 36-1 trigger wheel
- Ford EDIS-4 control unit, coil pack and VR crank sensor
- engine management, be it Megasquirt,Microsquirt, VEMS or other.
- necessary brackets and wiring
7. Take car off road and perform the upgrade, remembering to
- dial-in cam to optimum spec
- modify extractors to fit wideband Lambda sensor
- get on it dyno and develop alternative maps for max performance and economical running
I'd hope this investment should yield at least 190 bhp (~ 140 Kw) which is what the BL Rally spec engines reportedly produced.
If this didn't seem enough and my wallet wasn't empty then Stage 3 would be to turbo charge, but I would then want to strengthen the bottom end with ladder.
I'm very interested to hear others thoughts on this.
[:p]