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Discussion Starter · #1 ·
I have been searching past posts and have not quite found what I am looking for.

I am hoping to squeeze a little more power out of my 'lil Rav4. I am not racing or looking to do any engine swaps at this time.

My main idea is tweeking the basics: intake, exhaust and fuel. I have found info on intake and exhaust plumbing but have not really found info on fuel.

Here's the question: Can I upgrade the injectors for a little more fuel?

Hoping for a little more bang. If I can make the little engine breath easier and provide a little more fuel, I am hoping for a little more reserve power. I live in the Denver area and I do go out to the mountains for some fun driving. I am not trying to make a rock crawler but the last time I went out, I was going up a 7-8% grade at over 12K feet up and I ran out of gerbils! I got a little tow from a fellow driver and once the grade came down a little I was fine driving again. The help I needed was very small and it was a bit frustrating! I know these are not power houses but I feel 5-10 more horses would have offset the elevation.

So, my plan was was a freer flowing intake path with larger pipes, OBX header with 2.25 exhaust out the back and hoping to increase injector size. Any help will be appreciated.
 

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I found that using premium gas gave my prior car and truck a little more power when going on those high mountain trails and passes.

A supercharger would help overcome the low air density even better. :)

P.S. Weight reduction, e.g., removing the rear seat, etc. (without compromising safety), before the drive will help too.
 

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Discussion Starter · #3 ·
I would love to add a supercharger or turbo charger and not to be greedy, just to offset the air density! I don't think that the weight reduction will work, as it is the family mobile and the baby needs the back seat!

I will start with the intake and keep track of the butt dyno results. I also have an old APEX A/F piggy back that I might add to give it a nudge in the right direction.
 

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So, my plan was was a freer flowing intake path with larger pipes, OBX header with 2.25 exhaust out the back and hoping to increase injector size. Any help will be appreciated.
That is a great start. My suggestion is to take away the 'increase injector size' part and replace it with premium/higher octane gas. 91-92 if you can.
 

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Except for the K&N air filter my Rav4 is stock. I'm 50 miles north of Denver and am often over 12,000 feet without any problems, last August I took my Rav4 to the top of Mount Evans and that is over 14,000 feet. I use premium fuel as anything less at this altitude pings too much for my taste.
I do tend to drive my Rav4, like it is stolen. If you want these little engines to pull, keep the RPMs high.
As to weight, my Rav4 is always loaded, mostly with the safety gear everyone is supposed to have in their car.

Make sure the AC compressor is off on hard pulls, but it is useful to have it on during descents as it helps the engine braking power.
 
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Bigger injectors won't be an upgrade... the ECU will see richer condition via the O2 sensor, and will reduce injector's opening time to come back to original A/F target.


In fact, you would gain some power by leaning the OEM settings. If you had a wideband, you would see that stock A/F ratio is way too rich in wide open throttle condition. With your piggy-back you should be able to reduce you injector's opening time at WOT to obtains 12.5-13 A/F and get better power (N/A).


With an N/A engine, bigger exhaust size is not always better. A benefits of an equal length header is that you don't need bigger exhaust size, because none of the cylinders exhaust at the same time. Other important thing is that mandrel bent pipes flow much better than press bent pipes. With a good headers and mandrel bent exhaust; 2" is perfect for your engine.


If your engine wants to die going through a steep hill (and if you have a manual transmission), you can do a quick clutch-kick to keep it alive and get back again in a higher RPM's range for more power... I do it regularly!
 
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Discussion Starter · #8 ·
Except for the K&N air filter my Rav4 is stock. I'm 50 miles north of Denver and am often over 12,000 feet without any problems, last August I took my Rav4 to the top of Mount Evans and that is over 14,000 feet. I use premium fuel as anything less at this altitude pings too much for my taste.
I do tend to drive my Rav4, like it is stolen. If you want these little engines to pull, keep the RPMs high.
As to weight, my Rav4 is always loaded, mostly with the safety gear everyone is supposed to have in their car.

Make sure the AC compressor is off on hard pulls, but it is useful to have it on during descents as it helps the engine braking power.
Thanks, it is good to hear from someone that is in the area. I will have to run up Mt. Evans and see how she does for comparison. I did another trail outside of Empire that was between 8,500 and 10,500 and only had problems on steep sections. I pulled the 'ol iPhone angle finder out when going down and found the rough sections to be around 20° of angle. Anything less than that didn't give too much trouble. The trail that I petered out on was Kingston Mountain and I am pretty sure I was around 20° plus over 12,500 in elevation, once the angle came down, she powered right on.

Commando, I would love to do that but, she's an auto! I would get a running start at most hills!

I thank everyone for the help and will keep you updated as I go!
 

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Bigger injectors won't be an upgrade... the ECU will see richer condition via the O2 sensor, and will reduce injector's opening time to come back to original A/F target.

In fact, you would gain some power by leaning the OEM settings. If you had a wideband, you would see that stock A/F ratio is way too rich in wide open throttle condition. With your piggy-back you should be able to reduce you injector's opening time at WOT to obtains 12.5-13 A/F and get better power.
Correct on both points. During all but all but WOT the system is in closed loop and will adjust the AFR to 14.6:1 regardless of injector size.
At WOT any richer than 13:1 just wastes fuel and at altitude even 13:1 takes less fuel not more. EFI vehicles have barometric sensors to track air density changes. That's why they run so much better with altitude changes than carburetted ones ever did.
 
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The road to Mount Evans will close Tuesday morning if you want to run it this year you will have to hurry. Always closes the Tuesday morning after Labor day.
 
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