Dear HPI

I agree with you Im2lazy, Fiream could use a new motor however that would include a new header too so you r at $150 now. a new head and carb would be at most $80. and it will bolt right back together without worrying about motor mounts and mounting the clutch with the correct spacing.

Fiream, If you want a new motor that I know fits for $80 would be the Dynamite .12spd. Your track seems short so being a little short on power would not hurt you as much as on a bigger track.

I am running the Dynamite .12R a 3 year old motor and no one get's me by much even on a long straightaway.

Your choice...

PS: I am running the same tires you have, and no one believes it at my track. My car is a HPI RS4 racer. I am serious use the set-up I gave you before. It will work for you with those tires.

Im2lazy

it really depends on your competition. My competetion is mostly a bunch of guys that have what seems like an unlimited supply of money that they can throw at their car, so power is a big thing b/c our straight is pretty long, and our in-field is tight so you need power at both ends. Just follow the competition on this choice, and let your driving and set up do the rest.

FREAKAH

An MT12 is really all you need at our track or any track for that matter regardless of what other people are running. A NIB Mugen MT12 can be had for $130 on eBay.

Here's where pipe tuning(or type), clutch tuning and gearing really comes into play. Try running a Yokomo GT4(high overall gear ratio) on a small tight track and you'll see what I mean.

Don't waste your money on high dollar custom modified multiport turbo engines unless your'e in the Mod class but then again Kris Moore won our Mod class with a stock MR12 while everybody else had a modified or multiport engine.

Im2lazy,
Only a few racers at our track go all out with their cars and engines. Have you seen Wayne's car lately? There's dirt and fuel residue on it from three months ago but he still kicks a$$.

Concentrate on driving and the OVERALL tuning of the car and your'e set.

As for droop, I don't measure mine unless i'm giving out set-up info. I just make sure it's even left to right and just play with the droop screws while setting up the car. I use quarter or half turn increments on the allen driver during adjustments. My MTX-2 likes very little droop.

Im2lazy

All out for me is a would be a new pipe... course I'm not going to get one for my RS4. Seriously, after like a year of owning my rs4, I only got tires, fuel, glow plugs and desperately needed spare parts. All my plastic part pretty much should be replaced. Especially my front bumper... . Its so wobbly. I don't think I could sell it for $50 on ebay. I'd probably have to give it away; its seen more then it should have in its four years of life.

My pipe, (I've got to tell you all) is a mess. The bottom is all bare, scratched up aluminum. A lot of the anodizing has flaked off. The tip began to rip out of the pipe, so its held on by JB weld! There is a pocket in the side about the size of a quarter where someone hit my sideways at the end of our straight (marshall put me down sideways , i think he wanted to get away from the cars coming down the straight) The pressure line is now almost as white as it is purple. The fuel tank has a rip seamed together by shoegoo . The engines heatsink head has a build up of spit from me doing the spit test so much (I've been using other guys temp guns more often lately though) that is an unatractive brown that can be scraped off with my fingernails. my carburetor arm split ( the little plastic arm that is on rotary carbs ), and I had to fix it with JB weld and a zip tie ( ), and my rrp brake pads are almost worn through! That's my old race car

Im2lazy

When Kris moores MR12 and MTX3 were being raffaled (sp), I was taking donations b/c I was in dier need of a new car.

But now I have an MTX2 ( a large step up in performance). FREEKAH, I was wondering if you have rubber tire tips for this car b/c my car came from (if i remember Bobby correctly) Reynold, and it is setup for foams...

FREAKAH

I'll post my set-up later. Right now it's time to go to sleep. Zzzzzzzzzzzzzzzzzzzzzzzzz...............

Im2lazy

i'm still up, my medicine seems to be swearing by its side effects...imsomnia and a bunch of other stuff that you guys don't want to be hearing about. right now it is 2:18, at least I've got monday off from school.

Dear HPI

Have you tryed to open a two litre of coke without the knurling on the cap? The space allows a griping point that gets to the ground thru the dust. Also there is more air traveling around a treaded tire which blows the dust away sort of like water.

True a treaded tire on a prepared surface would give you less grip. AKA. Formula 1 went to the treaded design to slow the cars down.
That is why I use them on the front of my RS4. To take away traction.

Popsracer, HPI does make ball diffs for the nitro RS4.

popsracer

I had some pennies left over from building battery packs so here goes.

DearHpi:
I NEVER said that ball diffs are not availible for the NRS4.
I have a Robinson ball diff, but never use it because it is too much maintenance and I don't like the way the car handles with it.

Fiream;
The easiest way to measure droop on any car is with a ride height gauge.
After you've set your ride Ht. Place the gauge under the car again and keep going until the tires just get some air. Look at the mesurement. The difference between ride height and full extension is your droop. Both left & right tires should be exactly the same for best results.
Shoot for 2-3mm in the front and 3-4mm in the rear. This is a good starting point for the average racer.

Everyone;
The HPI Black springs are too firm for the back end of the car in most all conditions. Try Red or Yellow. White is a little soft and causes too much chassis roll.
Stick to no more than 2 steps difference between the front and back for better chassis balance.
I have tried the different tire type/compound thing in years past but find that the car is faster overall with a more balanced set-up.

Fiream

I'll probably end up getting some new springs this weekend... As for an engine, i've got my sights set on a Novarossi RX 21 R1 or something along those lines. I may also sell my HPI for a Yokomo...... I got to get HPI to handle better before I do anything....


RX 21 R1:

C. CAPACITY 3,49 c.c.
POWER 2.5 H.P.
R.P.M. 35.000
STROKE 16.80
BORE 16.26
PORTS 7
WEIGHT gr. 320
SHAFT Ø 14mm

popsracer

Try the set-up that I have posted on this thread. I have raced HPI cars for 3+ years and these are my recommendations based on those years of trial and error and what has worked good for myself and others I know.

Dear HPI

Fiream

You know what I just relized? I've got spring spacers in between the top of my shock and the spring... Could this also be my problem????


Rob

popsracer

I personally would not call ball diffs on a HPI nitro car an UPGRADE.
I've ran them and I don't think that there is any perfomance advantage to warrant purchasing one.
ALL of the top nitro cars have GEAR diffs (exception NTC3) and there can be alot of debate on how good the NTC3 diffs are or aren't.

popsracer

The plastic spacers between the springs and the top of the shocks are supposed to be used for setting the ride height.
Race shocks have threaded collars that do the same thing. Spacers are fine. HPI makes some thin clear plastic spacers for fine adjustments to the ride height.

We were both online at the same time and I pulled my message back for editing probally when you were just trying to read it.
I ALWAYS find something else that I want to say AFTER I submit, so I go an edit.