RPM Limit Question

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poetic

Guest
Hi All,

im in the middle of doign a Primera GTiR conversion and am going to send my ecu off to jwt to get it maped to suit the new engine!

they raise the RPM limit to 7700rpm as a rule but i can ask for a higher rpm limit!

but whats the max rpm i can ask them to set up before it becomes dangerous!

can i ask them to set the rpm limit to 8500rp and will that be ok on a stock block??

thanks, Jason :D
 
Nad

Nad

Active Member
There was a post on here a while ago if u have a search. I think IIRC that rpm is limits by max piston speed or something along those lines, to the point where it heats up too much.
 
P

poetic

Guest
thanks for the reply mate,

have been doing some searching have found posts about how to achieve 9000rpm

and theres another one aobut mines ecu doing 8500rpm, but it doesnt say if thats on standard internals or not!

thanks
 
S

str_motorsport

Guest
mines ecu has a rev limit of 8000 rpm.
i have one and have the maps of the mines ecu too.
you can run 8000 rpm with standard internals mate.
 
Fast Guy

Fast Guy

Moderators
Staff member
str_motorsport said:
you can run 8000 rpm with standard internals mate.
Click to expand...
But with standard cams you'll have run out of power by then so fit uprated ones to make use of that rpm limit :wink:

You can also overrev the engine to almost 9000rpm on standard internals :oops:
 
C

chris-b

Guest
fast guy- why do you say that? how is it possible without damage?
 
Fast Guy

Fast Guy

Moderators
Staff member
chris-b said:
fast guy- why do you say that? how is it possible without damage?
Click to expand...
Because I missed a gear change big style when I was giving it some in first and when I looked at the rev counter it was just under 9000rpm :?

The engine survived tho. :shock:
 
J

jonee

New Member
revs

hi

the guy mario from exvitermini.com has seen 11,100 rpm from a sr20 engine.the engine was put into a 200 sx.

cheers jonee
 
D

DavidGTiR

Member
poetic said:
Hi All,
im in the middle of doign a Primera GTiR conversion and am going to send my ecu off to jwt to get it maped to suit the new engine!
they raise the RPM limit to 7700rpm as a rule but i can ask for a higher rpm limit!
but whats the max rpm i can ask them to set up before it becomes dangerous!
can i ask them to set the rpm limit to 8500rp and will that be ok on a stock block??
thanks, Jason :D
Click to expand...
Hi mate,

If your sending the ECU away its not getting properly mapped. It has to be done "live" whilst working on the car and driving it. It sounds like your just getting a piggyback added. This chip will have enhanced settings to suit a modified engine but its far far better to get it all done whilst in the car and running.

The RPM limit should be set around 500rpm after the engine starts to lose power. There is no point (except for pub bragging rights) for it to rev any higher as there wont be as much pull/force till you change up a gear and get back into the rev range/powerband.

RPM is like BHP. People like it to be higher because it sounds better/cooler when infact more BHP (peak) doesnt actually mean more performance if its too high up in the rev range. Ideally you want more torque than BHP. Just because you can rev your engine to 9k+ doesnt mean jack (except v-tec engines :twisted: ). Once you have a car dynoed read the graph and understand where the power is and drops off. You will then need to shift gear to suit.

I seriously recommend you look into all of this further as you could gain far more performance and more importantly, driveability. :D
 
A

ashills

Active Member
the guys i buy off in the states go on about how good teh wolf ecus are all teh time
but what they normally do is get a re written ecu by them then put on dyno and lean out a bit with a piggy back like afc etc as the wolf ecus are all mapped very rich for safety
its normally about $400 for a ecu
 
K

kizzyturbo4x4

Guest
trust him.
i used to own a Vtec Machine...
and thats the smoothest powerband ive ever experienced.
"it just keeps goin and goin and then it even goes a little more"

the R has alot mor power but its like its only there once over a given rpm and under another rpm. much closer and sharper powerband.
but i would say the thrill in cars is how much G u can achive when giving it all
:D
 
J

jiw

Guest
it all depends on what grade of balance an engine is balanced to in the factory, most automotive engines are a g2.5, they are normally balanced to the rev limit plus 10% to cover for any overspeed which may occur so if this is the case with the sr20 det engine would be on its limit between 8250 rpm, then vibration may start to occur, this is probably why mines raise the rev limiter to 8000rpm and leave a little head room for over revving, jeff :wink:
 
P

poetic

Guest
DavidGTiR said:
poetic said:
Hi All,
im in the middle of doign a Primera GTiR conversion and am going to send my ecu off to jwt to get it maped to suit the new engine!
they raise the RPM limit to 7700rpm as a rule but i can ask for a higher rpm limit!
but whats the max rpm i can ask them to set up before it becomes dangerous!
can i ask them to set the rpm limit to 8500rp and will that be ok on a stock block??
thanks, Jason :D
Click to expand...
Hi mate,

If your sending the ECU away its not getting properly mapped. It has to be done "live" whilst working on the car and driving it. It sounds like your just getting a piggyback added. This chip will have enhanced settings to suit a modified engine but its far far better to get it all done whilst in the car and running.

The RPM limit should be set around 500rpm after the engine starts to lose power. There is no point (except for pub bragging rights) for it to rev any higher as there wont be as much pull/force till you change up a gear and get back into the rev range/powerband.

RPM is like BHP. People like it to be higher because it sounds better/cooler when infact more BHP (peak) doesnt actually mean more performance if its too high up in the rev range. Ideally you want more torque than BHP. Just because you can rev your engine to 9k+ doesnt mean jack (except v-tec engines :twisted: ). Once you have a car dynoed read the graph and understand where the power is and drops off. You will then need to shift gear to suit.

I seriously recommend you look into all of this further as you could gain far more performance and more importantly, driveability. :D
Click to expand...
hi mate,

the reason i am sending it away to JWT is becaue i am useing my Primera ECU on the GTIR engine because i dont want to loose my NATS(alarm)

i dont think it would be able to be maped live due to the ecu still thinking i have the standard primera injectors not the 444cc ones.

AFAIK jwt are one of the best companys for ecu tueneing, all i had to do was say i want my ecu told it now has:

3 bar for GTIR engine
8:3:1 comp
Z32 MAF
444cc
they also remove the top speed limiter.

i have been told that the fuel mapping is only goes up to 8000rpm anyway so it shouldnt matter if they were to completely remove the rev limiter, is this true?

also what would you say are the best cams to go for?
thinking of also uprateing my Valve springs
also do you need to get better rocker arm stoppers for GTIR's?? because AFAIK the lifters on the GTiR's are solid?

thanks foor all you help with this really appreciate it :D
 
D

DavidGTiR

Member
They dont really tell the ECU anything about the other parts added/fitted. They piggybacks just have general settings to go by like Superchips, chips. Live mapping allows you to adjust fuel/boost/ignition etc under load in real time so it by far the best option. Nobody is "best" in ECU mapping. Iv seen Motec people muck up before. The mapping should only go on what boost/power/capability the engine is built for

If your going to run 1 bar then it would be advisable to get it mapped past that incase you ever increase the boost and for safety.

There is no reason why you should remove the rev limiter at all ! Its there to save your engine and not for you to remove and see how cool it is to rev the engine sky high. It will only end in one thing, a dead engine and ££££.

Cams, the choice should be yours only. How would you prefer to drive the car ? What are you going to use the car for 1/4 mile, drag, fast road. All this will help you choose the right profile. Too mad and it will be undriveable. I chose 264 HKS cams as the power is exactly where i need it (midrange)when i race my car (fast road) so i can put my foot down in any gear and have smooth progressive power which in the real world can be a lot faster than "wild" cams. Your cam choice will determine about the valve springs. Higher lift cams will require uprated springs to prevent valve float etc or you could get them any for peace of mind. Same with rocker stoppers.

I dont mean to sound like a dick head but car modders should know the basics about how engines operate/perform. Spend a little time looking at web sites with info on all the parts etc before you make any choices/purchases. Do a search on google or something mate. :D
 
P

poetic

Guest
DavidGTiR said:
JIMMYBACK B said:
3 bar u sure :shock: thats an awlful lot :shock: :twisted: :twisted:
Click to expand...
Think he ment 3 bar MAP sensor :D
Click to expand...
yea 3 bar Map

thanks for all your help david + everyone else, i was looking at the 264 hks cams just interested what sort of makes you guys go for!

what companys do RAS for the gtir, because have checked out Greddy and cant find for the GTIR head jsut the SR20DE

i also have a SAFC so will get that tuned to livetime, but hopeing later on may go for an emanage!

thanks all
 
D

DavidGTiR

Member
I think you should skip the plug-in piggyback stuff and go for at least a Unichip. I know someone that works at Dastek and looked into the ECU`s features and its top kit really for the costs involved, i dont care what enyone says. I dont want a £2000 ECU that has a coffee maker or data logging. All i would want in an ECU is for it to be of good value and for someone local to be able to map and re-map it if i add further mods. Lots of my friends have had them fitted to thier Honda`s and the feature i like the best that can be added is that v-tec doesnt come on, on partial throttle. Only full throttle. You would also be amazed at what other features the Unichip has.

http://www.dastek.co.uk/unichip.htm

Where about do you live ?

No probs for any help so far. Thats what everyone is here for my friend :D :D :D
 
P

poetic

Guest
i live in hampshire mate, the unichip may be worth concidering if i decide to put a bigger turbo on, and therefore have to uprate injectiors..etc.

save sending to jwt again..etc.

thanks
 
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