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Engine Run Time

Engine Run Time

Old 06-22-2008, 06:52 PM
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Default Engine Run Time

I am currently running a GRP 21 Tuned On road engine in a MRX-X 1/8 scale. I am only just getting 5min runtime. If I do one extra lap it runs out of fuel. How can I improve my run time ?
Thanks
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Old 06-22-2008, 07:31 PM
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Use a smaller restrictor in the carb. Use the 2013 pipe. Loosen the clutch spring a bit. What gears are you running? What % nitro fuel? 25% will give you more run time then 30%.
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Old 06-22-2008, 07:59 PM
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Originally Posted by THE DOCTOR
Use a smaller restrictor in the carb. Use the 2013 pipe. Loosen the clutch spring a bit. What gears are you running? What % nitro fuel? 25% will give you more run time then 30%.
I am using 17/20 50/47 gearing. The pipe is a GRP 3008 FLS system with long header Our rules state 25% Fuel max. I will try a smaller carg restrictor.
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Old 06-22-2008, 08:25 PM
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I use this engine and can make 5mins with fuel left over.
Lean it out mate
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Old 06-22-2008, 08:35 PM
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Originally Posted by PROVK
I use this engine and can make 5mins with fuel left over.
Lean it out mate
All I can get is 100-110 C. If I go a bees dick more on the top end, it runs out of fuel on the straight.
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Old 06-24-2008, 04:33 AM
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I bought a GRP to my MRX4X too and I would like to know which glowplug do you use. The manual recommend #6 or #7 but I was reading in a Off-road forum that they are using #5 even #4 with 7mm restrictor. What are you using on on-road GRP?

Last edited by Wascheck; 06-24-2008 at 10:03 AM.
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Old 06-24-2008, 04:41 AM
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In Brazil you would be using a #7 for sure
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Old 06-24-2008, 10:10 AM
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have you tried using a different brand of fuel?

try one that is supposed to have "greater mileage"
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Old 06-24-2008, 10:35 AM
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This might sound stupid, but have you tried being gentler on the trigger finger?
I have plenty of racing buds that don't get near the mileage I do (and they get heavier tire wear too), but they're all the types that are very heavy on the throttle even on the short straights and twisty bits.
During practice sometimes I'll find myself searching for different lines and speed, and I always find myself getting worse mileage (tank time) than during racing. I'm generally heavy on the throttle, but only when it's neccessary and useable.
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Old 06-24-2008, 01:02 PM
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Originally Posted by advfuel
I am currently running a GRP 21 Tuned On road engine in a MRX-X 1/8 scale. I am only just getting 5min runtime. If I do one extra lap it runs out of fuel. How can I improve my run time ?
Thanks
Here are a couple of suggestions to improve run time;

1) use a lower % of nitro - this will require that you lean the High Speed Needle and it will give more run time.

2) add a .1mm shim to the engine - this also will require that you lean the HSN which will give you more run time.

Lee
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Old 06-24-2008, 04:02 PM
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advfuel

I added an extra .1 shim as reccommended by the best tuner and GRP Australia distributer "Rob Reade"

As I said I have no probs at all with run time
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Old 06-24-2008, 04:14 PM
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Thanks for ya input guys . I have only ran the car at 3 races so I will try a few of your adjustments.
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Old 06-24-2008, 06:24 PM
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I think that the 16 tooth first gear pinion will give you a lot more punch and you will find yourself not pulling the throttle so hard off of the turns.
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