R34 Basic Upgrade Questions

[wipe]

hi all,

ive had an R34 25gt for about a year now

so far ive only got a cat back 2.5" exhaust with a cannon muffler

i am curious to know what power is gained or lost through this modification as i have seen people say that you gain power and others have said that you lose power.

i would also like to know what i could do to increase shift speed as it is semi-automatic and at times it is rather slow with its gear changes.

thanks

[HackerX]

I doubt you'd lose power with just the cat back, but you won't gain much either. Better off finishing the exhaust off with extractors etc.

For the auto, do the same thing the turbo 34's do and get the valve body upgrade (you'll have to search it, there's a few threads around in the transmission section)

[GTS4WD]

People loose power because they go spastic on exhaut sizes. This increase of size creates a loss of back preassure.

i.e.. Now this will most likely be a dodgy explination.. but ill give it a go:

If you have a small exhaust.. the exhaust flow is restricted.. and there is too much volume of gas for the exhaust diameter.. causing it to slow down..

If your exhaust is the right size.. the gas will flow freely at a very rapid poit as it has reached it a point where everything flows at max velocity. Essentially.. the gass proppels and makes it self go faster through the exhaust. It accumilates speed throughout the exhaust and exists the car quickly, and effortlessly. If this is done correctly.. and at an optimum level.. GREAT gains are to be made (have heard of 25 dyno proved KW made by a cat back.. hi flow cat.. Headers and down pipe)

If the exhaust is too big.. the gass kinda just lingers there.. dowsnt know what to do.. and has a slow rate. Hence.. loosing power

BIGGER IS NOT ALWAYS BETTER!

2.25 - 2.5" is usually the right size you want for an NA

Suggestion 1) finish off your exhaust. with the lot. Mandrel bent etc. etc.

In terms fo your gear box..

I DO NOT KNOW IF THIS WILL WORK FOR R34'S AND I DO NOT TAKE LIABILITY OF THIS. I am simply showing you information that already is there..

YES.. this is GHETTO mod..

YES.. that wire is probably usefull..

YES.. it probably causes damage.. (throw a swich in to flick on and offf when needed)

http://www.skylinesaustralia.com/forums/in...howtopic=141351

Ill let you decide if it is for you or not..

[wipe]

hackerx,

i remembered the guy said something about i already had 2.5" extractors or something like that.

i dont really know much about the mechanics of a car unfortunently so i dont understand everything i'm told or read which makes it a bit harder.

on that same line, i am wondering what a valve body upgrade actually is and wondering if anyone in my area does it.

gts4wd,

unfortunently i dont really know what "the lot" is if you could maybe give an explanation on that, and about the gearbox solution....i have read that one and i really dont think id wanna take that chance with my car as i dont really want to cause damage, but thanks anyway.

thanks

Edited July 13, 2007 by wipe

[Eug]

cris:

the term you are looking for is volumetric vacuum. where the gases being expelled causes a plunging effect and continuously draws out the new exhausts gases. nice explanation there though.

kel:

2.5" extractors probably means your join pipe, primary and secondary pipe sizes play a vital role as well.

try a search, most of the stuff has been covered in and around the forums and in depth as well. try searching for mv automatics (mike, i believe his name is). he does the valve body upgrades hackerx mentioned, basically makes it shift harder and faster.

if you dont know that "the lot" is, i suggest you try reading around the internet to get a feel for the basic fundamentals on how an engine works and the components involved. what i would guess cris means with "the lot"; would be extractors, catalytic converter, cat back exhaust going to the muffler/cannon.

the concept is simple, air goes in, fuel is added, spark occurs and an explosion occurs, the gases from the explosion are expelled through an exhaust system. try to visualize the process and pin point where what happens, when and where. what a place to start by opening the hood of your car and trying to follow the path i mentioned before. start at the intake and go from there.

cheers

[GTS4WD]

Suck squish bang blow

Thanks clearing that up Eugene..

Heres a fantastic site..

www.howstuffworks.com

Type what you are trying to understand.. (eg. automatic gearbox, combustion engine, turbo etc. etc. etc.) Quite clear and simple explinations and clear diagrams..

wikipedia is also a good source.. aslong as some deadshit dosnt write it..

and its DEFINATELY a good idea to understand the basics before you do anything to your car.. so you know what happens.. why its better how it will change.. forums have a WORLD of information.. and missinformation..

Give it a few months and you will be a guru..

[HackerX]

It's easy enough to tell whether you have extractors or not.

Pop the bonnet and look for something like these:

Extractors (thanks to whoever's car/pic that is)

As Eug said, the primary and secondary pipe sizes play a role in the power gain (plus where in the rev range it comes in) for the same reason as mentioned above with the volumetric vacuum.

If you're unsure, but still ready to upgrade, then your best bet is probably to take it down to a recommended local exhaust shop, have them stick it up in a hoist and then tell you your options

MV Automatics is definately what I meant, it's on my list of things to do with my 34.

Other than that, you're best off searching in this section for all the usual NA mods to do.

[GTS4WD]

It's easy enough to tell whether you have extractors or not.

Pop the bonnet and look for something like these:

Extractors (thanks to whoever's car/pic that is)

mmm.. sexy.. Im not too sure about the bodgy red silicon.. dont know how many KM's thats gonna last.. but you know.. everyone needs to go through the bodgy stage of modification sooner or later!.. just too see the dangers and negatives involved with it..

[Eug]

haha yeah the red stuff does look quite dodgy eh. it's just gasket glue... should melt away or disappear in due time.

those are the coby extractors with hp coating on ignuz's car... hp coated shiny'ness

[wipe]

thanks for the help guys...i will start a bit more reading up on some of it ( like on howthingswork.com ) and i am also going to have a look under the hood for extractors so i know whether i have them or not(i guess there at the rear of the engine considering they are to do with the exhaust?).

Eugene,

MV automatics seems to be in SA if i am correct and that is a fair distance for me as i live on the northcoast and am not exactly up for sending it that far.

I have been looking around the forums since i found it about 6 or 7 months ago and normally if i see something it is either way to expensive for me atm or there is a dispute on whether it is a good thing or not.

thanks

Edited July 13, 2007 by wipe

[GTS4WD]

welcome to the wonderful world of modification

usually.. if you do you research on products.. or ask.. or search the forums.. you get an answere..

[Eug]

thanks for the help guys...i will start a bit more reading up on some of it ( like on howthingswork.com ) and i am also going to have a look under the hood for extractors so i know whether i have them or not(i guess there at the rear of the engine considering they are to do with the exhaust?).

open the bonnet, it's on the right hand side of the motor. there should be 6 pipes branching together.

Eugene,

MV automatics seems to be in SA if i am correct and that is a fair distance for me as i live on the northcoast and am not exactly up for sending it that far.

i think MV automatics possibly does an exchange program. many people have sent their valve bodies down to him to get work done. my mate has should be recieving his auto drag box from the same guys (and we live up in queensland).

each to their own, if you search around you might find someone who can do the job locally. research around.

hope that helps

[MissR34]

GREAT gains are to be made (have heard of 25 dyno proved KW made by a cat back.. hi flow cat.. Headers and down pipe)

me got a 3" catback and gained 16.9 kW!!!!!!!!!!!

[GTX-R34]

GREAT gains are to be made (have heard of 25 dyno proved KW made by a cat back.. hi flow cat.. Headers and down pipe)

me got a 3" catback and gained 16.9 kW!!!!!!!!!!!

Hi, love those headers, did you get them custom made or of the shelf. And if you dont mind me asking, how much were they?

Thanks.

[Eug]

me got a 3" catback and gained 16.9 kW!!!!!!!!!!!

peak power doesn't mean squat though...

[MissR34]

yeah i know Eug, just sounds nice LOL

as long as my car is running right (which it is not at the moment) all is good, im a bit over the whole "need to have massive kW's to have a good car......you need have a turbo....that is annoying me the most at the moment) i just got my extractors fixed yesterday cause they were leaking...didnt have to pay nething cause it was under warranty.

but i got a clunking noise happening when i turn the car on........got a sneaking suspecion its got something to do with the timing belt....get it looked at next week

[wipe]

Eugene,

i have had a look and by the looks of it i dont have extractors so i might look into getting my exhaust finished off with headers,extractors etc.. and i might look locally first to see if i can get the valve body upgrade and if not maybe look into sending it down to mv automatics.

i'll get a picture later and put it up so someone may be able to double check me.

Edited July 14, 2007 by wipe