nbesheer Posted July 5, 2007 Share Posted July 5, 2007 I always thought that engine braking used more fuel because of higher rpms. But right now I just thought that the engine was spinning faster not because of more fuel but because the wheels are making it spin. sorry if this doesn't make sense or is a completely stupid question. By the way I have a 5-Speed -Nick Quote Link to comment Share on other sites More sharing options...
OlderThanMe Posted July 5, 2007 Share Posted July 5, 2007 surely having your engine at 800 RPMs under braking is using than less fuel than downshifting at 3k+ RPMs. When I am driving on curvy roads I'm always using a mix of heel-toe downshifting. That means using both brakes and the engine to decelerate the car. The way my brake bias is setup (stock) the fronts will lock and there isn't enough rear bias. it gets a little squirrily under hard braking coming into sharp turns. If you are driving normally then just use your brakes. Pads/rotors are cheaper for stopping than the price that gas is... Quote Link to comment Share on other sites More sharing options...
hughdogz Posted July 5, 2007 Share Posted July 5, 2007 If you have the stock EFI, then the answer is it depends. If you are off accel and above 3500 RPM, then the fuel is cut to the engine. I heard this eats a lot of oil through the PCV, but I'm not sure about that. Quote Link to comment Share on other sites More sharing options...
nbesheer Posted July 5, 2007 Author Share Posted July 5, 2007 I do have stock EFI but how is fuel cut after 3500 ? does it just not inject fuel and the vacuum pulls it out or something ? I'm really not worried about the gas thing it's just theres this hill between my house and my grandmas house and it's like 15% grade or something i don't even know if that's the right number but its pretty steep and riding my brakes down it seems pretty scary since it's a long hill. Quote Link to comment Share on other sites More sharing options...
Shift Posted July 5, 2007 Share Posted July 5, 2007 Uhh..... I think he's reffering to breaking "IN" an engine. Am I right? Short answer is yes. Generally, higher RPMs = more gas. Now there are load factors that can very the amount of gas used. Quote Link to comment Share on other sites More sharing options...
Pop N Wood Posted July 5, 2007 Share Posted July 5, 2007 Don't take your car out of gear on long down hills. It is generally considered to be unsafe. If your engine stalls, you lose power steering and brakes. Plus you do put a lot of load on the brakes possibly overheating them. I But I wouldn't downshift so many gears that the engine is screaming. Just enough to hold the car in check. Quote Link to comment Share on other sites More sharing options...
Tony D Posted July 5, 2007 Share Posted July 5, 2007 Engine braking souldn't use any more fuel, and probably less... Like stated, EFI has 'fuel cut' that basically shuts off the injection system when the idle contacts are closed and engine RPM is above X point, and it will not restart fueling until below 2500 rpms to keep from stallingthe engine. On a carburetted car, the throttle closed puts the idle circuit in play, and even though you have a high vacuum, the idle jets on their best day can never flow as much fuel as you would lopaing on the mains with the throttles even BARELY cracked. now, if you are engine braking and blipping the throttle you can set up a situation where in both carbs and EFI you are getting fuel from the main circuits in both instances, and then you defeat the purpose.... So if you are engine braking, do so on closed throttle and you will save fuel! Quote Link to comment Share on other sites More sharing options...
nbesheer Posted July 5, 2007 Author Share Posted July 5, 2007 okay pretty much what I do is I go over the top of the hill doing about 35 in 4th and I quickly go to about 60+ MPH at 3000+ RPM still in 4th with no throttle. But that is cool that it doesn't use that much fuel Quote Link to comment Share on other sites More sharing options...
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