Mike Rainbird

iTrader: (3)

He's also running only 2° of ignition, which seems crazy low to me, and could be why he is still seeing such high EGTs (however, I don't know enough about the rotary engines to know if this is normal - but I always thought this is what killed the rotar tips). However, on a piston engine, you would be wanting a minimum of double figure ignition, as having it heavily retard sticks huge temps into the turbine, which can transfer back into the head and cause pre-ignition or for the valves to melt and drop out .

I wonder what would happen if he ran less boost and more ignition advance? We need Stavros to comment now, as he has an RX7 with 500bhp, so maybe he knows what kind of ignition these engines like?

Char1ie

iTrader: (6)

This is very very minimal from what I've read. ERL experts have examined turbos that have run with pre-turbo WI and seen no noticable wear over a year. Also Saab turbos used to run pre-turbo WI and reckoned their turbo would last 100k miles before replacement.

Having said that the water needs to hit the turbo as a very fine mist so as to not cause damage and therefore the atomiser/injector needs to be very effective.

Charlie

Char1ie

iTrader: (6)

My turbo sits behind a 36mm restrictor preventing large volumes of air from entering. If the air can be cooled then the car can make more power.

Charlie

Char1ie

iTrader: (6)

Reading now. Sounds like a very simple system.

Charlie

turbotoaster

are you running about 2bar of boost and 300bhp?

even though for example your running alot of boost, your not not moving a massive volume of air so adding alot of water wouldnt be a good thing as you will blow the spark out.

I would suggest 300cc of water for your setup, i think a aquamist 0.5mm jet on there pump is 220cc, but thats only been chucked into air at say 40c+

300cc should be fine when chucking it into 100c+

Will be interesting as if your compressor temps are alot cooler you can make maximum power for the air you have to play with.

One thing i thought about was from my renault 5 days, the carb on them was 24mm in diameter and what we found was most of the top r5s maxed out at 230-245bhp on a that carb. Kind of like 34mm restrictor stopping a cossie doing more than say 340bhp

There was a guy named stuart who i helped develop his car, still on original carb, and we can pre trubo w/i and he eventually put out about 350bhp with no nos. Now that is with a 24mm restictor on it, for proof he did 11.4 at 126mph so the power was there.

foreigneRS

if your ecu can support it, why can't you inject it after compressor and before i/c where the charge is hottest and it will take the most energy out and run it in a closed loop depending on i/c outlet temp?

as for the i/c filling up with water, why not put a drain back to the tank out of the bottom of it if regs allow (an oil separator may be needed)?

Char1ie

iTrader: (6)

Running around 18psi and 290ish BHP. I think it'll work. I like the sound of the boost driven set-up - more water for more turbo boost. I'll update once we've started installing.

Charlie

jammerrs

that does seem like a very good system, also very basic to run

well if it doesnt work you havent lost anything and potentially have a lot to gain imo

turbotoaster

the reason for the low ignition is because you wont really gain a massive amount of power from loads of ignition on a rotary, hes letting the boost make the power instead of igntion, plus on a piston engine you ignite your fuel once, we ignite it twice as we have a leading and trailing spark plugs.

We normally run around 14-16c of ignition at peak torque on 1bar of boost and then a little bit more above but only a tiny bit.

another rotary with a smaller turbo at over 500rwhp was tuned found a mere 8rwhp loss by lowering the total timing by 4 deg. Given this was an 8" tyre RX3, this ammount of power was never to be realised or noticed, so he left the timing out. the insurance level added into the combination was far greater than 1 or so % of total power.(the car went 9.6@148mph, big traction problems,toyota box, full street car) I hope you understand what I am saying.

Hes running 34psi on pump fuel, you run anymore than what ignition hes running you will either get an extra 10whp or it will blow, not worth it on a 700whp engine

Mike Rainbird

iTrader: (3)

Those kind of EGTs seem dangerously high to me, but it depends if he is measuring them pre turbo or post turbo?

But that is what I meant by a piston engine being different, you don't really want it to be so heavily retarded, as excessive heat kills engines / turbines.

GARETH T

mike have you ever seen what ignition angles some big power evos are running?

turbotoaster

Yeh rotarys run really high egts, anything under 1000c pre turbo is normally classed as safe, though some guys go up to 1050c and there engines hold together.

I might be because we run really big turbine A/R to get the heat out fast, a standard mk2 rx7 turbo has a 1.00 A/R turbine housing so im guessing mazda realised this and used that to help.

Also even though alot of guys run bb turbos its not really ideal due to the massive heat, probably ok on a streetcar but on a track/race car id want a journal bearing one.


But as this isnt really a rotary thread id rather not clutter up charlies thread, saying that by the sound of it hes already going pre-turbo with that mechanical system i suggested, it will be interesting to see how he gets on as im sure another say 30bhp from more boost would be brilliant so catching them other cars

james kiely

iTrader: (5)

can the water be cooled by a secondary radiator for the wi tank indirectly using a coil[like in a home cpper cylinder for example],and would this have any affect on getting the temps down thus allowing the use of a smaller jet to be used

cheers james

turbotoaster

not really mate, if your using a radiator at best you can lower it down to ambient temperatures so not worth it and to be fair most people will use the windscreen wiper tank because that way you can check how much water you have left by pressing your washer jets, and that tank is normally in the scuttle so not normally red hot....it depends how much water you need though, id say for charlie he will need 7 litres for a race. and i doubt that will fit there so its tricky in an engine bay as there isnt alot of room.

If it went behind the bumper on the drivers side there is a risk he would bump into another race car, damage it, loose all the water and blow the engine, he could run the tank in the passenger footwell but then that depends whether they will alloy him liquids in the car, even if it is only water.

Im sure charlie has an idea on that

james kiely

iTrader: (5)

i see what you mean mate


cheers james