Short RAM and engine tuning

[tozza6]

Hi guys,
I recently put a short RAM my 89 Accord Si (A20A4 engine) and i have noticed that the mileage has decreased and the car seems to bog down a bit when taking off. At high RPMs it runs well but round town driving is not the best. When putting a short RAM or any air intake system on is there some specific tuning you should do to the engine. I am not focused on the performance issue but more the economy because i do 500kms+ a week.

I understand that you cant adjust the air/fuel mixture (am i right?) without chipping the ECU. Would advancing the timing a few degrees fix this problem? or would a good tune up be in order - i had the car serviced a few days before i put the intake on, couldnt wait unfortunately.

Let me know what you guys think!
Thanks
James

[AZmike]

Have you reset the ECU yet? It's not too hard. Open the under-hood fuse box and pull the ECU fuse (10A). Leave it out for a few minutes. Reinstall it and start the car and let it idle for a few minutes. Have you read through any of the threads in the technical-fuel injection section?

[Busted_Blue]

I thought we were suppose to disconnect the battery for a few hours.. Am I thinking wrong?

[tozza6]

Ive checked for ECU codes, nothing
Ive reset the ECU - i used the d/c the battery for a few mins method, i find it works better.
Ive also checked the PGMFI section, havent found anything much
Thanks for the ideas so far, keep them coming!!!

[A20A1]

What size/style is the filter?
I say this cause the inlet for the air could be causing turbulence.

Do you have all the hoses hooked to the intake?

Also when you oepn up the intake the car takes in more air so it adds more fuel... hot air would decrease performance and also heat up the car more, any number of factors leading to decreased milage...

Hows the tire pressure?

also the stock air box may have an effect on the amount of plenum vacuum behind the trottle body... or the rate that the vacuum drops... meaning the stock air box would retain the vacuum advance longer then say removin the intake pipe and running a straight throttle body.

So you, I'm guessing will need to make adjustments to raise your vacuum advance, or get it to hold longer or advance the distributor.

one way I increased the vacuum hold time was to intall a large rubber vacuum holding tube connected between the manifold and the vacuum advance diaphragm... this keeps the vacuum from dropping too quickly and should help in your situation.

[A20A1]

oh also you can connect multiple vacuum lines to the holding tube... one line will be without a check valve the rest will be with a check valve... that may or may not increase the vacuum recharge time, and since only one line will bleed vacuum, it should decrease the vacuum drop time.

Just a theory.

[1988starter]

Are you using a breather or ataching the large tube to the intake. Are there any disconected vacume lines.

[racerx]

hmm, when i went to a short ram from stock, it sounded better, but i can't say it performed all that much better...

when i went to a CAI, the performance gain was phenominal, comparitively. I don't know why, but my engine just didn't like the hot air any more than the stock intake.

also, i believe the A/F ratio is adjusted by the ECU only. I wouldn't mess with it unless you're going to boost the motor. just my $.02

another thing, my engine seemed like it couldn't detonate all the gas and stuff in the combustion chamber. it seemed like there was no increase in power between 70% throttle, or 100%. I got an accel coil, accel wires, and NGK v-power plugs, gapped to .050 and that actually made a big difference too.

but for a nice, cheap fuel efficiency upgrade, I say opt for punching out the cat!

[A20A1]

The hot air isn't the full cause of the drop in performance since I've ran an efi car with cold air conditions feeding the short ran and it still has the same problem of the studder before taking off... adding the vacuum holding for the advance helps elliminate some of the problems.

Also note that the cold air intake is a much longer tube which affects the vacuum.

[tozza6]

Thanks for the replies guys, i might look at the vacuum advance, or advancing the distributor.

[racerx]

just for everyone's info:

my friend just ran his car at the track the other day. He drives a 99 grand am SE, and the track is at 7500 ft.

He put his short ram intake on, and ran an 18.020
Then, with the cold air on, he ran a 17.620.
I didn't know cold air made such a big difference.

[AccordAddict]

holy shit! with cold air he got a gain that good? i think im going to get an integra cold air intake now.

[AccordAddict]

holy shit! with cold air he got a gain that good? i think im going to get an integra cold air intake now.

[racerx]

yeah, i know. we were both very surprised. i'm getting a CAI for my prelude now too.