Rev Limit

[ichyraay]

Can anyone suggest a way to remove or modify the Rev limit on my Pr3 ECU Its a stock 1991 lx Accord 5 Speed ecu not too many options unless you guys know anything, My rev limit kicks in at 6500 which is ok for my current setup but I plan to port the throttle body and intake manifold with the turbo so I going to need more room in the powerband that config is going to make plenty of power upstairs after 6K, especially with the long F22 gear ratio, any Idea's (no standal one ECU's Please, the goal is budjet _

[WiKKeDV16]

eh.. personally.. u dont need to go all that much past 6,500 to make good power.. past 7k ur just asking for trouble.. it still is a stock bottom end.. so i say thats ur limit 7k.....

i believe u can buy a msd ignition.. and it allows u to adjust the rev limit.. not sure if it bypasses the ecu's cut or not.. but.. im sure someone will chime in and reply.. but under boost.. i just dont see the point in revving much higher thats just asking for a snapped rod..
tis my opinion anyh00t..

so what type of turbo setup u going for.. DIY? or some prefab overpriced kit... u can tell my favortism... lol

[Slateboy]

You're going to need to focus more on boost creep, and properly tuning your engine. If you don't focus on that, then you're gonna blow the shit out of your motor. Before you go around showing your BOV around town, get it dyno tuned. Otherwise you're going to blow it up.

What are you using for management? You SHOULD be using something like an AFC, E-Manage, or AEM EMS.

Your powerband for the motor is not determined by the transmission. If you want to take advantage of the short powerband of the F22, then get a more aggressively geared transmission. It will reduce your top speed, but your acceleration rate will be increased. Honda's were never made for top speed anyways.

If you increase the RPM limiter, which would have to be digitally through either a piggyback computer, or a standalone aftermarket application, then you're looking for problems. Your motor as it sits was designed to make its power before 6500 rpms. If you took it further, it would feel like a limp dick.

If you build your head, then maybe you'd be safe increasing the RPMs. We're talking stronger valves, springs, etc. Without, you'd drop one real quick. I don't know about you, but I like my valves IN my head, rather than on top of my piston.

[WiKKeDV16]

Originally posted by Slateboy
You're going to need to focus more on boost creep, and properly tuning your engine. If you don't focus on that, then you're gonna blow the shit out of your motor. Before you go around showing your BOV around town, get it dyno tuned. Otherwise you're going to blow it up.

What are you using for management? You SHOULD be using something like an AFC, E-Manage, or AEM EMS.

Your powerband for the motor is not determined by the transmission. If you want to take advantage of the short powerband of the F22, then get a more aggressively geared transmission. It will reduce your top speed, but your acceleration rate will be increased. Honda's were never made for top speed anyways.

If you increase the RPM limiter, which would have to be digitally through either a piggyback computer, or a standalone aftermarket application, then you're looking for problems. Your motor as it sits was designed to make its power before 6500 rpms. If you took it further, it would feel like a limp dick.

If you build your head, then maybe you'd be safe increasing the RPMs. We're talking stronger valves, springs, etc. Without, you'd drop one real quick. I don't know about you, but I like my valves IN my head, rather than on top of my piston.

eh .. why is it that ppl always bust out with the most expensive routes for engine management..

so many options that are almost FREE

uberdata being one that works on the accord

and yes ur right thou.. he needs to worry about tuning more than increasing the rev limit.. regardless.. the f22a tranny is fine.. closer geared just means more quicker shifting.. not always faster accel if he cant keep the tires on the ground..

the only tranny id upgrade to is the h23.. but thats just an opinion

regardless..

get it boosted
get it tuned
then work on making it more efficient for ur higher revving goal..

[Slateboy]

Reving higher is only possible if you build the motor and head. I'd just get it tuned, and maintain.

[ichyraay]

Rev Limit

Thanks for the advice, didn't I mean to come off Naive, I'm very concerned with tuning, I refuse to drive my car once it's turbo'd anywhere but to my local tuning shop, there's a dyno with a Wide band O2 wating for me so I know where I'm making power, where I'm detonating, and where I start to run lean. Trust me I'm not some kid running around town trying to impress, nothings better than a smart, comfortable turbo setup. As for engine Management I will be using:

MSD 6al
MSD BTM (Boost Timing Master)
Apexi SAFC II
DSM 450cc Injectors
AEM Fuel Rail
1:1 Fuel regulator
255lb Walboro Fuel pump
ARP Head Bolts/Rod Bolts
Turbo Head Gasket
NGK Iridium Plugs (Colder Of Course)
Custom Front Mount intercooler......

Now If that's not a safe setup for 7-9psi I don't know what is. I'm only concerned with my rev limit beacause my power band runs smack dab into the limit, its supposed to taper off or flaten when approaching it's limits (obviously I'm looking at a my recent Dyno chart not guessing) it's still on an upward curve, that's what makes me feel I should remove it and use the MSD Soft limiter which I can control based on when my new Dyno graph says after the turbo project, you can't use stock restrictions when you change the engines characteristics as drastic as a turbo, I'm looking for another 500-1000 rpm maybe 7500 that's all. I'm not certain that my stock ECU is the best for this engine so I'm interested in the JDM P39. And yes your tranny plays a huge part in where your engine makes power the same relation as your Hp at the crank is different from what's at the wheels. Your car can only go as fast as your gears let it. H23 Trannys a good choice

[WiKKeDV16]

i still feel thats pushing it on the bottom end.. ur asking for a snapped rod i tell you..

7,500 would be a MAYBE thing N/A but turbocharged.. thats alot of force your applying at that high of an rpm.. i believe the rev limit stock is suppost to be 6,800rpm.. with its original ecu.. dont quote me on that. but i believe thats the original limit.. so i dont see 7,000-7,200 being that extreme.. but when ur snapping 7,500 while under boost.. ur just asking for trouble.. i know these motors arnt that expensive but still.. keep the one u have alive.. and keep it safe.. u can make PLENTY power by 7k.. and its understandable about the power drop off.. with ur mods and cams im sure it keeps climbing.. how much farther u dont know thou.. im gonna throw a wild car and say by 7,200 or under it stops pulling.. n/a of course.. for that high revving duty you should of got a 2.0L

[ichyraay]

Rev Limit

I agree all this can only be determined by a dyno I'm not going to guess or assume, I refuse to have a blown engine on my hands, got a wife and kid you know, no time for mistakes

[MRX]

http://www.cb7tuner.com/vbb/showthre...highlight=fuel

questions:
whats a "turbo head gasket" and where'd u get it? what makes it "turbo"? we already have a low enough compression

why use a 1:1 FMU if you already have the Safc to add fuel? The combination of the 450cc injectors, an fmu and the safc is like buying 3 shoes for your 2 feet. Just use the combination of the 450's and the safc i'd say. I mean it should be fine but i'd say just get a normal fuel pressure regulator. I have an AEM FPR that i might sell PM me if ur interested and ditch the FMU.

why'd you get a fuel rail?

[Slateboy]

Obviously a stock-internal F22 should be run with low lbs of boost, and a smaller turbo. However, if you NEED to increase your redline, on the F-block, the F22-vtec head and P0a ecu are both built around I think a 7500rpm cutoff.

FYI.

[92accordDx]

you dont need to rev the motor that high. im sure 6800 is pushing it after you rev it that high so many times expecially for stock bottomr end. its just waiting for something to go

[ichyraay]

FMU

Never posted that I had a FMU, it's just a regular Fuel Pressure regulator, Fmu have larger ratios like 8:1, 12:1 and so forth, it would'nt help with larger injectors though, I'll use it only to increase the pressure just a bit over stock, the AFC pertains more or less to the duty cycle of the 450 injectors, if pressure isn't sufficient then you can't optimize those bigger injectors, they flow a bit more over stock, just giving my tuning guy somthing to work with, fuel rail I had laying around, might as well use it, it sure looks nice You guys have convinced me to leave the rev limit alone....for now

[MRX]

actually there are several discs u can interchange with FMU's and one of them is the 1:1 ratio disc. If it raises fuel pressure under boost then its an FMU. Not being a dick just stating the facts ya know. Anyhow i wish u the best of luck with ur tuning.

[quadnie]

I think I would up the boost before I upped the rev limit... just my personal opinion

[N1ghtM0nkey]

What I don't understand is why anybody would put mods that help in the higher RPM ranges (above stock rev limit) onto the car.

Don't know if this makes much sense, but why wouldn't you want to make more power where it's safer to do so. I don't see much reason in raising the redline if you choose parts that make more power below it than above it.

Example - smaller turbo that spools sooner and dosn't run out of breath before 6,300 RPM or whatever stock rev limiter is set at.