Re: 2.4 JTD uprated gearbox enquiry - Kev
Thanks for the comments -
The car is the 'problem' not the gearbox - the engine has been worked on for 2 years or more now ongoing and without details it's got to engine stripped - race build, balanced, lightened for a diesel.. sump work on oil returns and baffles - heads cleaned up and exhaust ports cleaned up but retained oe sizes.
Uses a modded VNT and the stock ex manifold cleaned up - we tried steel manifold pipes but spent every other week welding them up and it made little odds to the power or spoolup. But major odss whne it drops off. The ex system turbo back is all janspeed custom fit - they had it for a day and did a lovely job in 3" - the cat can be slid back in if required...
The air pipework all samco, ally tubes, the intercooler again has been front mounted but we went back to a custom plate corner mounted and improved air flow throught the bumper and arch. (see later why - )
EGR's gone, egr body and plumbing all gone, the egr valve's still there to keep the ecu happy! Proper oil catch tank systems and modded breathers to avoid any embarrassing oil spills onto unfortunate places - front tyres sprung to mind.
Fuel etc - the ecu's delimited, the rail pressure set up by 400bar on the mechanical limiter on the Hp pump. The pumps also got larger pistons and cylinders. (Australian pump) The ecu map is set for max rail pressure, 25 psi mean boost wot - running dry - it peaks about 28. No limp home, economy, idle control, there's some control function between fuel rail pressure and ambient air temps and engine coolant temps - again removed. It's a proper stripped out ecu file..
Range Rover V8 MAF - works well with the incresed air rates and does not go off the scale.
The injectors are up appx 12% fuel flow rate using 2.8JTD van bodies and maxed out noxxles/needles and lift settings. They run well on a stock car oddly enough...
Steel custom made flyweel - this was made up by a race prep company that have them made up weekly for formula fords etc - the unknown was how it would all run with only about 40% of the Dual Mass weight and a solid clutch centre plate. Well it seems to run much better than the standard set up... the plate is good for 600bhp petrol - which in petrol vs. diesel power/torque scenarios makes about '350 diesel bhp' - the plates take a long time, 1000 miles or so to bed in but when it grips - it really grips. The one piece flywheel made to pattern was cheaper than Alfa wanted for a dual mass. With so much less weight - it now revs more freely in lower gears.
Then one of the highlightes as far as mods go is the water injection system, it's a high capaicty high pressure fogging system - over 160psi and it's set up to deliver about 300 ml per minute of fluid - the fluid can be just water, or water meth mix, or water/meth/nitro mix. The latter is worth 60bhp and about 100nm. With the water kit humming the boost is then 32-35psi mean. Needs good turbo which we seem to have found - and lots of 'clips on the boost pipes'! The intake air temps drop so dramtically with the water kit in use - not a petrol kit - that we moved the front mounted cooler back to the nsf corner and went for a high flow corner mounted bar and plate rad - improved the air flow through it, this gives much shorter and less restrictive plumbing runs from the turbo to the rad and to the engine, we saved about 4 90 degree bends and allows better pipe expansuion rates. The whole thing just drove much better with the proper corner mounted cooler and shorter pipe runs. BUT - with these sorts of mods it does need the water kit running anything much over 20psi.
It uses an auxilliary fuel control unit too over the mapping to enable some fuel rate control to be had for events etc - thats works really well and can be programmed easily and switched in and out.
Obviously a lot of big brakes - 6 pot tarox, KW's and alfa GT 18" wheels with some mods on the wheel bosses and also rolled wheel arch flanges to clear the wheels - but looks cool - otherwise the aim was to keep the car 'stock looking'.
The guys who have done the work are race prep and race drivers/trainers etc - and just do 'lap times' not dyno bhp figs. The last time and that was a year ago before it was anywhere near this stage it was 270bhp and 600nm - ave of 3 runs. It's over 300bhp now and the torque i can't even imagine - the 600bhp petrol clutch just holds it in 5th. The impressive thing is that it appears to have the same massive torque and power in any gear at any rpm - it's never caught napping. The first gearbox lasted a year, the second about 6 months, this is the third to go - and it needs fixing really now - but as you know - alfa diesel tuning bits are not easy to come by.
Whats it all for? - daily use and fun, we use it at goodwood on odd track days, when we know being locals we can embarrass some serious bits of kit (&rivers) - the cars been properly race prepped re suspension, corner weighted, all the geo and angles done and redone - I drive it and i'm NOT a race driver but it's so so easy to drive - I use a BMW 330 3,0d a lot too with 18" sports pack M3 wheels etc - also set up properly and to be totally honest and it's an unbelivable thing to say - i have more trust in the Alfa now to turn in! And it outbrakes the BM thanks to some huge Tarox custom made discs 320mm and calipers.
The next job is sort the gearbox - so it needs some work there now which we are looking around for ideas on - all the things we have sorced - the gearbox is looking to be the one thing thats defeated us.
The water injection system is having a proper digi controller made for it now that will work on load and rpm - that will help save on the water refills more than add power. We are going to test more than one jet and jet postioning on the dyno with some proper air temp work .The air con return pipes still have to be run round the alloy pipes off the turbo - thats an air con mans job and is wating for a convenient day - that will freeze the ally turbo outlet pipe with some minor air con plumbing - again lower air intake temps more power and safer engine - no loss in interal air flow rates.
Then - and thats going to be September we'll get a proper dyno session to benchmark it - that will be all the major mods done - but there's normally 10-15% more then from fine tuning...
Sorry for the amount of words - and i've probably missed 5 things off the list - the nett result is yesterday I'm losing to a red scooby RA but it has 480bhp and 1100kg - and i only lost to it by about 2 cars lenght a a ton - the scooby is a mates car and he's just ordered a 850bhp safe engine - to make sure in a couple of weeks i'm not going to be overtaking him - i'll still be able to get 300 yards on the normal roads when he's trying to drop 3 gears and i've launched it in 5th at 60mph with no gear changes needed before 150....
Boys toys - don't ask how much it cost i'll never put that in writing as it will be used in the divorce courts - but to be able to slip it into 2nd from standstill - discreetly nail an M3 off the line whilst having a normal conversation with the mrs, the kids and full tank of derv and luggage - and no one realises whats going on - is just so much fun.
I'll never get rid of it - irrespective of budgets it's just had so much time and skill put in by some guys who love cars and racing - the race guys who helped have gone from 'we don't work on diesels' to looking forward to the next project - as they know from experience of all sorts of race cars - 'torque wins races' - and nothing provides more torque, Lemans 24hr... power to the dervs!
Oh - seeminlgy irrelevant - but it still does 40mpg driven normally..