Kendall

iTrader: (1)

I've got a 960 and MEGA .21 DSII with the MEGA 2033 pipe and #203042 conical header with a 9mm venturi. I'm looking to make 5 minutes or longer for a qualifier.

I have tested the 8mm and 7mm venturi's to improve mileage but they only lower the powerband of the engine. The 7mm has also slowed my laptimes.

Any suggestions for improving fuel mileage?

M7H

Hmm, I can make upto 6 minutes with that combination......
I run at (or even below) sea level, 25% Nitro, 0.6mm Head clearance.....

dj apolaro

Man I ran this weekend at the kissimmee track in Florida and what a track. Those of you that can come should try to one day. I had some very bad luck all weekend, but man I ran my Maxy Modified zx12 and it was awesome. I definately had one of the fastest motors, if not the fastest. I set the fastest lap time of the weekend. Thanks for the motors Maxy and thanks to serpent-usa for the constant support.

D.J. Apolaro

Winner's Circle

iTrader: (2)

You can add a .1mm shim to the engine. This will require that you lean the top end resulting in longer run times. The trade off is slightly lower torque. The other thing you can do it go to a lower nitro percentage. This too will require a silght leaning of the top end resulting in longer run time.

duneland

I bought the power pack for my 960. I was surprised to find that I had far better performance with almost every other exhaust system I tested! After several different combinations were tried, I settled on a short nova rossi conical coupled to a Dynamite (that's right DYNAMITE!) 86 pipe. No problems with run time. 6 minute range depending on track & gearing.

Kendall

iTrader: (1)

I do have the .1mm shim added. I was thinking I could try a NON conical header, if not that, just lean it out and hold on!

Kendall

iTrader: (1)

I'm running 30% at sea level with .6mm clearance.

Are you running the 9mm venturi?

Are there others at your track with the DS-II and the same combo:

2033 pipe
203042 header
0.60mm clearance

Are they still making 5 minutes with fuel to spare?
Or should I just drive slower?

roadrage

iTrader: (14)

hi guys. i have a question. i heard from the serpent team that on the zx 12 you have to run the low end rich. why is that?

M7H

I use the 2033 Pipe, with the header which came with the 2018 combination, when I bought my Mega "DS I" (R.I.P)
2018 combination:
http://www.mytsn.com/products/imggal.asp?prid=3831
Header:
http://www.mytsn.com/products/desc.asp?prid=3021
But also with the "normal" 203042 I can't recall having fuel problems......
Yes, I run the 9mm venturi......

Maybe the track I run on is smaller then yours, it's the MACH track in Holland, but this is not a small track at all.....
Maybe my driving style is more "smooth" than yours, because I have a smooth "throttle" style....

In Holland there are not many running the DSII engine, because of the problems with the DSI, and the fact that a lot stick to the idea that when something is not expensive, it can't be powerfull.....but maybe this will change next Year....
I had several questions asked to me what I think of the reliability of the DSII so far, I think it is ok, my engine is 5.5 liters old now, still has pinch, and the rod is still in good shape, I will change it for next year, but it still looks great.....
The speed is there, proven by me several times , when outrunning a lot more expensive engines, but again, this just might be because my driving style, and the simple fact that a lot of drivers have to much power in there cars which actually slows them down.....

I will stick to the DSII engine, but this is also because I won a second engine by finishing 2nd in the Dutch "Serpent series".......
http://www.mytsn.com/news/publ.asp?pid=12133

M7H

Because the engine likes it that way....
If you lean the bottom to much, it will damage the plug, and flameouts will be the result......

Kendall

iTrader: (1)

------

emankov

Hi ppl,
I need your comments for my first aquaintance with the DS2.

My purpose was to bench-run an ZX21DS2 powerpack legal brand new
Muffler=Efra 2018
Plug=Turbo 7 cold
Fuel=Tornado 16%
No filter used
Heat gun
Middle venturi from the powerpack

With default settings i start the engine in a bench.
I keep the lowest possible rpm for 15 mins.
I notice a lot of fuel come out from the exhaust, unburned (default settings are rich).No smoke at all
After 15 mins of suspiciously stable operation at low rpm and max temp about 120F, i proceed to the next step
Fuel consumption so far about 75ml....
I stop the engine and i refill the tank (125ml total).
I start with 30-40 % throttle. No smoke at all still unburned fuel come out of the exhaust.
I start to mess with the main needle to lean her. I didnt notice any BIG difference even with 2 full turns on the lean side (!)
Max temp through the whole proccess was 170F, and that was achieved after i rev up to 60% throttle for a few secs (some smoke came out then but not a lot)

I believe that the engine never got up to normal operating temperature due to the bench propeller but again am not sure.
Anyway after 30 mins of 30-40% throttle, fuel consumption was approx 100ml.
The engine keep to run so stable that i still cannot comprehend. Not a single flameout or some flunctuation in the sound when throttle was stable. Maybe i am not used to that yet..

I stopped the process cause i couldnt figure out how lean i am. Fuel Consumption says am very lean, smoke says am not, and engine temp cannot help me at all.
I reset the main needle to default.The other 2 are untouched from the factory settings.
Glow plug wire was clean and a little wet, except the start of the wire which got black.I checked it with a toothbrush and i manage to clean it somehow, so the wire is ok from start to end.

I plan to tune the engine on the car using the startbox, cause i think i wasted my time with the bench.

Plz feel free to comment, cause right now i dont know if i misused my DS2.
Thx in advance

mrgsr

iTrader: (15)

why only 16% ?? you should be running 25% in .21
then again this depends on what your legal nitro limit is

you should run the engine in with the fuel your going to use

M7H

I don't see anything strange in your story.
that you didn't notice any difference even when closing the main needle for 2 additional turns, is correct.
If you would WOT the engine, so full throttle, then you will notice difference.
Not a lot of smoke from an engine which is not under load, is also normal.

My advice, open the main needle 1 full turn from default and run the engine in at WOT (Wide Open Throttle) in your car, on the startbox keep the rpm as low as possible (but steady), by adjusting the main needle, this way the RPM should be so low that your wheels will not spin.....

Do this for about 2 tanks (done in a few minutes) and let the engine cool down completely for about 30 minutes.
run the same process again, and after the next cooldown periode, close the main needle until your wheels start to spin at WOT so it would be possible to run the car on the track (maybe you also need to loosen your clutch)

Run the car on the track and on every 3/4 of a fueltank close the main needle by 1/8 of a turn, until you reach the perfect mixture.....

emankov

Thank you both for your replies
..but..

"you should run the engine in with the fuel your going to use"

Both the bench manual and the engine manual, propose to keep the same "brand" of fuel through the engine life. Especially the bench manual proposes 16% for the break-in period and 25% for normal use (even if this change of nitro capacity requires additional needle work).

M7H u have to reprhase your comment, somehow, because i cant understand how WOT (full throttle right?) can coexist with low RPM and wheels not spinning.
Or maybe its me with my poor english.But thanks anyway