no top end power

carguyf545 · Post by **carguyf545** » Sun Apr 01, 2007 11:29 pm

my na 2.4 race car makes no top end power. it has mad power from idol to about 6000. after 6000 it just feels like im just hurting it to push it farther. i tried and it will only turn 7000. and it did not want to, but i made it.

i thought it was fuel, since i was useing the stock 240cc injectors. so i put the stock 4g64 injectors in. i think they are 275cc. the motor is running lean and running rich will not hurt the motor and it would have to be blowing black smoke to make so rich that it did not make any power. the 275cc made it run richer, but they did not help.

now im thinking that the stock maf(hacked) is not flowing enough to make the power. or i have a voltage drop so there is not enough spark. or the timing is retarding for some stupid reason. i dont think it is the timeing.

so next saterday im going to run the car with no maf. hope it pull hard all the way to 7500. it that does not work, then i will look at my wiring.

does anyone have some thoughts?

flatblackdime · Post by **flatblackdime** » Mon Apr 02, 2007 4:06 am

cams? Sounds like thats just your powerband...

Bill Hincher · Post by **Bill Hincher** » Mon Apr 02, 2007 9:24 am

Flash back is right, cam timing acts that way, but you could be running out of fuel too, maybe try larger injectors

Post by **DJpowerHaus** » Mon Apr 02, 2007 4:05 pm

How is the ignition timing tuned on there? I remember on my 2.6 that's how it felt when the mechanical advance wasn't working.

carguyf545 · Post by **carguyf545** » Mon Apr 02, 2007 9:24 pm

i used 2.4 cam gears. they are timed right by the marks, i thought it was cam timing, but the marks line up.

maybe the injectors out of the 4g64 are not 275cc, i thought for sure that they would help, but they did not.

timeing. the book calls for 5 degres, the motor sounds great about 7 degres, but it likes to ping. i thought it would like 4 degres cause of the piston speed. maybe i need to run some trick 101.

im not sure what the problems is and i only have one day aweek to work on it and i really can drive it, besides race day. and that is really limited.

the cams are stock 4g63 n/a, could it be that turbo cams might work better?

carguyf545 · Post by **carguyf545** » Wed Apr 11, 2007 6:37 pm

this last weekend i was able to make a couple of laps. so to test one idea about running out of air i disconnected the maf. the car ran good on the track, besides the fact it hit a revlimiter at 6k......duh.....

i was going to take more test laps, but it started to rain. so now i can try some more test on saturday.

does any one have any ideas???

peregrine · Post by **peregrine** » Wed Apr 11, 2007 9:52 pm

remember that the naturally aspirated motors were for point A to point B. you might just be better off getting a turbo on there.

Fabritory · Post by **Fabritory** » Wed Apr 11, 2007 11:04 pm

destroke dat bitch

carguyf545 · Post by **carguyf545** » Thu Apr 12, 2007 9:15 pm

i was thinking that the motor would run just like the 2.0 would, just with more power.

i would not think the stroke would stop the motor from makeing power up high. i know about rod ratios and stroke, friction loss and all of that good stuff. but turning the lower end 1000 rpm to 1500 rom faster than stock. i did not think the lower end would stop it from makeing power.

as far as i know something is not wired right, some how the cam timing is off(all of the timing marks line up). or im still not getting enough fuel.

with the maf disconnected it was running rich, but what about the 6k rev limit. shouldnt the rev limit be at 7500.

carguyf545 · Post by **carguyf545** » Fri Apr 13, 2007 9:39 pm

the revlimit should be at 7500. the motor has turned 7000, but it did not like it. the 6k revlimit came when i disconnected the maf.

i think smog got it right. the cams are for the 2.0. the 2.4 needs more air and the cams can not keep up the with the demand of the 2.4 lower end.

what is the difference between the n/a cams and the turbo cams?

the motor makes huge power on the lowend but not much on the top.(for a n/a stock motor.

Bill Hincher · Post by **Bill Hincher** » Fri Apr 13, 2007 9:51 pm

turbo cams are sensitive to the center line number ( meaning valve overlap)in a n/a engine with both exhaust and intake valves open at the same time, your exhaust headers are at thier peak performance, so you have a wider centerline number, it allows the exhaust header more time to work at a given RPM

with a turbo, you dont want too much overlap because of the forced induction so you have lower centerline numbers

carguyf545 · Post by **carguyf545** » Fri Apr 13, 2007 11:11 pm

i understand that, but i was wonder the difference between the stock cam profiles.

i can not use aftermarket cam gears. and i have no money for anything else. i have stock parts. so i have to build and make this motor run great with stock parts.

peregrine · Post by **peregrine** » Sat Apr 14, 2007 12:46 am

carguyf545 wrote:i understand that, but i was wonder the difference between the stock cam profiles.

i can not use aftermarket cam gears. and i have no money for anything else. i have stock parts. so i have to build and make this motor run great with stock parts.

straight up, go turbo.

Bill Hincher · Post by **Bill Hincher** » Sat Apr 14, 2007 8:33 am

well, you start out with a computer program to plan what you want, I use ' desk top dyno' and you get the cam profile library so you can see the results of each cam you try. I know its kind of expensive , but when you consider how much time and effort you have to put in to change cams and timing in the engine , it saves a lot.

there are a lot of cheap calculaters out here from like Edelbrock and Morroso that can help you build what you want

Post by **DJpowerHaus** » Sun Apr 15, 2007 3:48 pm

Any chance of finding a MD304189 (1994 Galant GS (DOHC 2.4L)) ECU?

*edit* car-part.com has plenty of DOHC ecus for like 75 bucks. theres no reason not to pick one up.

carguyf545 · Post by **carguyf545** » Sun Apr 15, 2007 11:23 pm

will it plug in to my harness????

i finally got it to go around the corner. i was pulling to 6k in third gear. thats about 78 mph. the car is really fast.

i turned an 18.09, the next fastest on the track is 18.85.

i have three weeks off, so theres some more tuning to do so i can go left faster. i will break into the 17's next race.

my partner blew a head gasget, so we are going to put a b18 in his 88 intrega

oh yeah, i won the heat and the main saturday.

Post by **DJpowerHaus** » Mon Apr 16, 2007 4:48 pm

If in doubt, go peek at a Chiltons and compare it to a 1G eclipse manual

FG64TOGO · Post by **FG64TOGO** » Mon Apr 16, 2007 8:07 pm

well, with your combination, i dont think you have any more room for valve lift. the 2.4 is 3 valve and the 2.0 is 4. those 2 valves come very close to the 1 valve relief in the piston. to be safe, the piston should be clearanced.

is there a speed sensor or something else that has been eliminated ? (like on the inst panel). seems to me the motor should pull at higher r's (6000 t0 7000) no matter what cam, stroke,or ecu. as long as everything is working correctly.

isnt the rule; more low end torque, more adv.
more high hp,retard?

way cool, you are making good progress. keep at it.
keep us posted. good luck.

carguyf545 · Post by **carguyf545** » Mon Apr 16, 2007 8:53 pm

there is not much piston to valve clearance. i did put knoches in the pistons for valve relief. i have more than .050 clearance. i dont know the # off the top of my head.

im going to go talk to a new local dyno shop and see if i can get a sponser. they have to tuneing tools i need.