David P

Superchargers are cool enough for me, maybe I am getting old

Should this thread be haunt of the photoshoppers, could you please 'morph' a pic for me. I would like to see this scoop on the Supra bonnet, the scale is not the same, the side would come about half way between the existing U.K. scoop and the line in the bonnet, and the front of it a couple of inches further back than the U.K. scoop front is now. Thank you.

You press the big button in the middle of the steering wheel.

Pic for bike lovers.

Don't worry Barney, i'm still tinkering along, other than the project, I have had other matters to attend to today. Yet still found time I to visit the engineers and rattle their cage to get the blower planed, they have had it for nearly 2 weeks now, a bit long winded for such a small job. They have promised it for tomorrow. The pre 92 4Runner cap has arrived, this is better than expected, and will give around 20mm more room than the post 92 version I currently have. This means I should now have around 30mm clearance to play with. Whilst under the bonnet I have relocated the HKS DLI, to begin making room for the throttle body. I have also been busy with the disc cutter, morphing the chargers' twin outlet into a single 90mm exit using the charge cooler off-cuts, but the final cutting cannot be finished until the charger is mounted.

It's too cold to go out and play, so I have found a bonnet with the bulge to model.

Barney, The link I posted to the Aquamist forum is very informative, inbetween the mind bending. In a nutshell, it would appear that to have both is best, water/meth 50/50 @ 170ccpm is a baseline figure I found recommended for 300bhp, you can calc up and down as a percentage from this to find a starting point for your target output. You will need to confirm that your w/m system is up to feeding 2 nozzles, and the 1/4 - 1/3 total delivery of pre charger feed will only be needed when on boost. I have decided to begin at 1 x 0.2mm nozzle before the charger, activated by a pressure control switch @ 8psi, and 3 x 0.2 jets after the charge cooler activated at over 1,500rpm and delivered fuel parallel by interfacing the Aquamist 2C with the MAP sensor via the AEM ECU. This will deliver up to 280ccpm whilst the engine is under max load and should be good for 500bhp. The ERL pump I have is good for up to 300ccpm, and the 0.2mm nozzles deliver 70ccpm, you will need to check the spec of the pump and nozzles you are using.

For all the years of chitchat re. T.T. tuning, I am amazed this information is unknown. Cams are costly items, and it looks a possibility that fitting an N/A inlet cam to a T.T. could be a very cheap way to add BHP to BPU. BPEU maybe?

No need to change the exhaust cam as they are the same. But looks like an N/A inlet cam could give gains, maybe Digsy could comment.

The spec for the N/A inlet cam is different too. Is there a Supra Guru who can advise which of these sites has got it right. This difference makes quite a difference to my dynamic compression calcs.

Sleep on the landing, you'll find out for sure then.

Looks like a Supracunundrum

These are the specs given for the J spec cams given on http://mkiv.supras.org.nz/specs.htm Intake valve dia. 33.5 mm Intake valve lift 7.8 mm Exhaust valve dia. 29.0 mm Exhaust valve lift 8.4 mm Intake opening 3 deg BTDC - 41 deg ABDC Exhaust opening 52 deg BBDC - 4 deg ATDC Very different to those posted by Nic. Which figures are correct? Has anyone ever considered fitting an N/A inlet cam to their T.T. Intake valve dia. 33.5 mm Intake valve lift 8.3 mm Exhaust valve dia. 29.0 mm Exhaust valve lift 8.4 mm Intake opening 3 deg BTDC - 52 deg ABDC Exhaust opening 52 deg BBDC - 4 deg ATDC

The engineer had a limp excuse for not planing the blowers bottom, the Main Dealers had forgotten to order the distributor cap and it is still too cold to be lying under the car making the pre rad brackets. Dejavue. I decided that the distribution knuckle can live without one of the support brackets, so have relocated a manifold pressure feed and have 'pruned' some more to give better lines for re-fab, this gives me access to make a better job inside and the finished item will look better too.

That has some ZIP in it

There was certainly plenty of hot air about cold air, and theoretical claims of up to 30%, yet I would be happy with the +10% air density @ 10oC below ambient that was actually achieved. So to conclude: Is my reckoning to begin with a pre charger 0.2mm nozzle activated at 8psi, and 3 x 0.2mm nozzles into the plenum operating when over 1,500rpm a feasable selection?

The 'good read' convinced me there are gains to be had, what I need is a starting point for injector nozzle sizes. Is my guesstimate anywhere near?

I have just read this thread, lots of info re. pre charger/post charge cooler water/meth injection. http://www.aquamist.co.uk/vbulletin/showthread.php?t=251 It appears that pre charger w/m injection can give a 10% denser charge, yet post charger injection is still required for det prevention. As far as I can ascertain for this build, to inject a 50/50 mix pre charger when over 8psi through a 0.4mm nozzle, and also directly into the runners at over 1,500rpm using 3 x 0.4mm nozzles, would be a good starting point, I will contact Aquamist to confirm this.

It certainly wasn’t a personal attack. I would have said the same whoever it was. No matter how careful a driver you may be, it must be obvious that it would be a lot safer with the correct tyre pressures. Regard it as being cruel to be kind.

Entiendo! I think I will leave out the simplistic equasions, they are too complicated. Re. cooling, I have a 13 row engine oil cooler plumbed after a Mocal thermostat behind the vent in the n/s wing and a gihugimous oil filter located in a cold draught, which combined also gives 2 litres capacity more than OE. The water cooling has a double capacity rad, a TRD stat, an electric pump and twin electric fans, which I believe to be more efficient than OE, yet in a previous post you have intimated not. However, the belt is to be reversed around the electric water pump idler pulley to give sufficient wrap for the s.c. pulley, so this is an integral and necessary part of the conversion. The headers are multi wrapped reducing under bonnet temps, there will be cold air ducted to beneath the charger and a large vent in the bonnet ramming cold air onto the head. The charger will be restrained to 11.9 or 13.5psi. Will this be sufficient cooling, or should I be looking at further options?

Adam, I understand your input re. isothermal compression and O2 partial pressures, maybe this re-hash of my simplistic equasion will make more sense. Pre charger water/meth injection = denser air = more O2 @ lower pressure = larger pulley = less work for belt. More O2 @ lower pressure = less detonation and keeps the s.c. @ around 13psi (peak efficiency) to achieve 500ftlb (maybe).

Pre charger water/meth injection = greater cfm @ lower pressure. With more O2 @ lower pressure, maybe the engine can achieve the trans max of 500ftlb with a 4.5" or 4.25" pulley. This would reduce the possibility of belt slip, lessen the detonation issues and keep the s.c. within the parameters of it's peak efficiency.

May as well brick up the rear window.

With your attitude towards motoring and road safety, you should not even be allowed a driving licence. I'll wager that you complain about the cost of your insurance policy too. One day, you may grow up and realise that it is dickthippery such as yours that actually cause the hiked prices in the first place. Fact and without malice.

If you're not up to checking your tyre pressures, then you're not up to owning a Supra.