BAJA SRT4 100cc gasoline twin cylinder 2-stroke 1/4 scale
01-20-2012, 02:34 AM
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RE: BAJA SRT4 100cc gasoline twin cylinder 2-stroke 1/4 scale
ORIGINAL: JariV
Johnny, please tell me how you know that? Are you ABSOLUTELY sure?
I think you are wrong. I don't see a problem with cooling when all the details are taken into account.
Yes, the STOCK engine rpm is around 8800 but this engine is not stock anymore. Ever heard about tuning? Tuning allows the engine to have more power over a wider band and with a tuned pipe you can extend the rpm band A LOT. Does the exhaust system look like it's a stock system for an aviation 2-stroke engine?
Secondly, the primary gears have been selected so that 10.000 rpms from the engine yield 60 mph speed for the car. That is only a starting point. And the torque coming from 100cc engine... well it's not lower that from a 23-30.5cc normal gas engines. Or 50 - 60cc engines.
Try to think outside the box and see the technical side. Not only catalogs or basic applications.
Johnny, please tell me how you know that? Are you ABSOLUTELY sure?
I think you are wrong. I don't see a problem with cooling when all the details are taken into account.
Yes, the STOCK engine rpm is around 8800 but this engine is not stock anymore. Ever heard about tuning? Tuning allows the engine to have more power over a wider band and with a tuned pipe you can extend the rpm band A LOT. Does the exhaust system look like it's a stock system for an aviation 2-stroke engine?
Secondly, the primary gears have been selected so that 10.000 rpms from the engine yield 60 mph speed for the car. That is only a starting point. And the torque coming from 100cc engine... well it's not lower that from a 23-30.5cc normal gas engines. Or 50 - 60cc engines.
Try to think outside the box and see the technical side. Not only catalogs or basic applications.
01-20-2012, 05:24 AM
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RE: BAJA SRT4 100cc gasoline twin cylinder 2-stroke 1/4 scale
Ok, we have different opinions about cooling. That's fine.
If you look closely it is not the shaft going to front diff that has a big angle but the one going to the rear diff. And yes it does have a lot of angle but still within drive cup limits. It is also silicone bushed inside. And it does not have practically any down or up angle, only to the right.
"Hell of a load to the engine"... okay I think I disagree here also. That engine is intended for an aeroplane in a 12-15 kilos weight range and it is supposed to power 3D aerobatic planes with ease with lots of G's and strong acceleration from hover. This taken into account I think it does not need to work extensively hard in my application. Tire traction will always be the most limiting factor of putting the power to the ground. I think the most obvious parts to break are various parts of the drivetrain.
Your first comment was very "attacking" by nature. Instead of saying "that is not possible" you could consider taking an easier approach. For instance asking questions. That would help other people too. With that kinda responses you only get people angry or irritated.
If you look closely it is not the shaft going to front diff that has a big angle but the one going to the rear diff. And yes it does have a lot of angle but still within drive cup limits. It is also silicone bushed inside. And it does not have practically any down or up angle, only to the right.
"Hell of a load to the engine"... okay I think I disagree here also. That engine is intended for an aeroplane in a 12-15 kilos weight range and it is supposed to power 3D aerobatic planes with ease with lots of G's and strong acceleration from hover. This taken into account I think it does not need to work extensively hard in my application. Tire traction will always be the most limiting factor of putting the power to the ground. I think the most obvious parts to break are various parts of the drivetrain.
Your first comment was very "attacking" by nature. Instead of saying "that is not possible" you could consider taking an easier approach. For instance asking questions. That would help other people too. With that kinda responses you only get people angry or irritated.
01-20-2012, 11:05 AM
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RE: BAJA SRT4 100cc gasoline twin cylinder 2-stroke 1/4 scale
Grille made out of aluminum, this is what it looks like on the body:
Here's the original 1:1 Mk1 Ford Escort grille:
And here's the grille I made painted to match the original style:
Here's the original 1:1 Mk1 Ford Escort grille:
And here's the grille I made painted to match the original style:
01-20-2012, 11:45 AM
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RE: BAJA SRT4 100cc gasoline twin cylinder 2-stroke 1/4 scale
You can look at the Losi also and that has a pretty good angle on the driveshaft,and there is no problemswith that,ifanything you will probally have issues withdogbones or drive cups likeyou disscused.
01-20-2012, 05:43 PM
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RE: BAJA SRT4 100cc gasoline twin cylinder 2-stroke 1/4 scale
ORIGINAL: JariV
Ok, we have different opinions about cooling. That's fine.
If you look closely it is not the shaft going to front diff that has a big angle but the one going to the rear diff. And yes it does have a lot of angle but still within drive cup limits. It is also silicone bushed inside. And it does not have practically any down or up angle, only to the right.
"Hell of a load to the engine"... okay I think I disagree here also. That engine is intended for an aeroplane in a 12-15 kilos weight range and it is supposed to power 3D aerobatic planes with ease with lots of G's and strong acceleration from hover. This taken into account I think it does not need to work extensively hard in my application. Tire traction will always be the most limiting factor of putting the power to the ground. I think the most obvious parts to break are various parts of the drivetrain.
Your first comment was very "attacking" by nature. Instead of saying "that is not possible" you could consider taking an easier approach. For instance asking questions. That would help other people too. With that kinda responses you only get people angry or irritated.
Ok, we have different opinions about cooling. That's fine.
If you look closely it is not the shaft going to front diff that has a big angle but the one going to the rear diff. And yes it does have a lot of angle but still within drive cup limits. It is also silicone bushed inside. And it does not have practically any down or up angle, only to the right.
"Hell of a load to the engine"... okay I think I disagree here also. That engine is intended for an aeroplane in a 12-15 kilos weight range and it is supposed to power 3D aerobatic planes with ease with lots of G's and strong acceleration from hover. This taken into account I think it does not need to work extensively hard in my application. Tire traction will always be the most limiting factor of putting the power to the ground. I think the most obvious parts to break are various parts of the drivetrain.
Your first comment was very "attacking" by nature. Instead of saying "that is not possible" you could consider taking an easier approach. For instance asking questions. That would help other people too. With that kinda responses you only get people angry or irritated.
01-20-2012, 06:52 PM
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RE: BAJA SRT4 100cc gasoline twin cylinder 2-stroke 1/4 scale
awesome build and the pipes are works of art... i cant wait to see and hear video of it running. again, great work.
01-21-2012, 05:40 AM
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RE: BAJA SRT4 100cc gasoline twin cylinder 2-stroke 1/4 scale
i love mk1 escorts with the rally arches, will look very good when painted up have you got a colour scheme for it?
01-26-2012, 05:51 AM
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RE: BAJA SRT4 100cc gasoline twin cylinder 2-stroke 1/4 scale
Have you started her up yet?
I would think IF you do have heat issues, you could use some ducting, if this does't help look into brushless turbine fans - i used one on my 57cc twin and it works a treat.
Craig
I would think IF you do have heat issues, you could use some ducting, if this does't help look into brushless turbine fans - i used one on my 57cc twin and it works a treat.
Craig
01-26-2012, 08:32 AM
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RE: BAJA SRT4 100cc gasoline twin cylinder 2-stroke 1/4 scale
I prepped everything today to be ready for the first start. I am still waiting for the sensors to arrive for the engine monitoring unit.
That unit measures cylinder head temperature for both heads and exhaust gas temperature for both cylinders and revolutions of the engine. It does all the functions simultaneously and has warning limits that set off a red color LED on. And a LCD display. So I will install that to the car and then I will be ready to fire up.
I measured the weight distribution of the car today.
53% of total weight on rear axle and 47% in the front axle.
Left side 49,5%, right side 50,5%.
I would have wanted 50-52% of the weight on the front axle so the manoveurability under full or partial load would have been neutral and no understeer (typical to 4WDs). I should have placed the engine a little bit forward than what it is but it was impossible to know exactly beforehand. I thought that position would have been enough.
BTW; all of you who have weight scales and a 4WD rc car please could you measure your cars corner weights? I would like to have comparison data. Post weights in driving condition with full tank of gas, either normal house scale or a fish scale. Measure the weight on all wheels. I would like to know what kind of weight distribution known brands have.
That unit measures cylinder head temperature for both heads and exhaust gas temperature for both cylinders and revolutions of the engine. It does all the functions simultaneously and has warning limits that set off a red color LED on. And a LCD display. So I will install that to the car and then I will be ready to fire up.
I measured the weight distribution of the car today.
53% of total weight on rear axle and 47% in the front axle.
Left side 49,5%, right side 50,5%.
I would have wanted 50-52% of the weight on the front axle so the manoveurability under full or partial load would have been neutral and no understeer (typical to 4WDs). I should have placed the engine a little bit forward than what it is but it was impossible to know exactly beforehand. I thought that position would have been enough.
BTW; all of you who have weight scales and a 4WD rc car please could you measure your cars corner weights? I would like to have comparison data. Post weights in driving condition with full tank of gas, either normal house scale or a fish scale. Measure the weight on all wheels. I would like to know what kind of weight distribution known brands have.
01-30-2012, 10:29 PM
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RE: BAJA SRT4 100cc gasoline twin cylinder 2-stroke 1/4 scale
Mudgy, I was considering that but decided that I don't want to repeat myself. So I decided on another color combo. The shell is being painted now and I should have it back later on this week. Let's see how it turns out.
Blaaaaah, still no word on the sensors. I'm expecting for them to arrive late this week too.
Blaaaaah, still no word on the sensors. I'm expecting for them to arrive late this week too.
02-01-2012, 04:45 AM
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RE: BAJA SRT4 100cc gasoline twin cylinder 2-stroke 1/4 scale
This looks like a fantastic build and it would be great to see a full grid of these at the first Finland RC federation meeting for largescale rally cars - I bet you could set it up in no time at all.
There are obviously many hours of R&D left to do but it's looking great so far.
Mike
There are obviously many hours of R&D left to do but it's looking great so far.
Mike
02-03-2012, 02:10 PM
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RE: BAJA SRT4 100cc gasoline twin cylinder 2-stroke 1/4 scale
We actually have a lot of 1/4 scale rallycars here. We also have winter racing series and summer as well.
Here's some picture terror:
Here's some picture terror:
02-03-2012, 09:46 PM
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RE: BAJA SRT4 100cc gasoline twin cylinder 2-stroke 1/4 scale
Thank you.
I'm ready to try to fire it up but the sensors didn't come in the mail yet. I'm not taking any chances with the engine so until I have the monitoring unit on I will not even try to start the engine.
I'm ready to try to fire it up but the sensors didn't come in the mail yet. I'm not taking any chances with the engine so until I have the monitoring unit on I will not even try to start the engine.
02-10-2012, 05:18 PM
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RE: BAJA SRT4 100cc gasoline twin cylinder 2-stroke 1/4 scale
ORIGINAL: JariV
Thank you.
I'm ready to try to fire it up but the sensors didn't come in the mail yet. I'm not taking any chances with the engine so until I have the monitoring unit on I will not even try to start the engine.
Thank you.
I'm ready to try to fire it up but the sensors didn't come in the mail yet. I'm not taking any chances with the engine so until I have the monitoring unit on I will not even try to start the engine.
02-17-2012, 10:09 PM
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RE: BAJA SRT4 100cc gasoline twin cylinder 2-stroke 1/4 scale
Ahh Johnny,
how many vehicles have YOU manufactured?
I would keep very quiet if I was you, until it's running. The egg on your face won't show that way[sm=47_47.gif].
how many vehicles have YOU manufactured?
I would keep very quiet if I was you, until it's running. The egg on your face won't show that way[sm=47_47.gif].