What makes a car rev faster and drop the revs faster? My 3.0L TR with no mufflers straight pipe out the back and just some mesh over the AFM will rev to about 6000rpm before it sounds like it's going to die... I normally change before 5800rpm when I'm booting it... Is there anything I can do to improve revability without taking the heads off?

I will be welding on a new muffler at the back though, its straight 2.5" pipe the whole way through from cat back, but even before the cat its decent size already but stock. I'll have to install a pod filter too, I have a chrome blitz one here from my skyline which I'll wack onto it.

lighter flywheel i think.. although then you would lose out on momentum and how much the car could roll

but i could be entirely wrong

Yea your probably right... but who rolls? Floor or it brake... hehe =)

Someone with more of a clue will no doubt correct me here..

You need to address two things. First is the ability of the engine to hold together at speed. This means making anything that moves lighter, and balanced. Secondly you need to address the ability of the engine to make power at high speeds. This means breathing. So you need as little restriction on the intake as possible. Same goes for the exhaust. But camshafts and intake systems are also designed to be most efficient at a particular engine speed, so you need to look at that too.

Of course that's if you want to make your engine spin to 7500rpm instead of 6000rpm. If you just want to stop it suffocating at the top of its range, any breathing mods are good, intake or exhaust.

Ok great. 6000rpm is good, but I just want it to rev safely to that without dying out... Also with less restriction on the intake it should make more power now... there is lots of carbon and oil buildup on the intake, especially in the valley, and porting all that out should help me a bit.

It would be really tricky... and I probably wont end up doing it, but do you think there is a way to seal up the top of the heads and port them a little from the top without taking them off? Then vacuum out the grinded metal? I'll probably do the rest of the intake manifold as its completely in pieces now. What are the problems with doing this with a normal drill? I know the die grinder goes at a way faster rpm.. which might get you a smoother finish(?) but I'm sure I could use a drill for the intake manifold as its only aluminium.

Also I have to find out about extending the runner sizes, because I could get a metal 'separator' plate between the valley and the intake runners to increase the size of the intake... or am I totally lost =) My old man's a boilermaker and could make me up something like that easily using a gasket as a template.

something ive been quite curious about for a while and will probably do myself if my car ever reaches the stage where I feel its needed is something called "extrude honing" they pump a abrasive paste through the heads and it files down the restrictions as it flows through, i saw it done in a magazine and it resulted in a 15% gain in the amount of air the head could pass through.

My suggestion, keep an eye on the forums and ring around the wreckers. find a set of heads get them extrude honed maybe get the surface decked a little to raise your comp and then swap them over. If your half way mechanicaly inclined once you have all the parts its a weekend.

As for hardcore rpms... parasitic loss is a *****. get a lightweight crank pulley made up, switch to a electric water pump, if you dont have a hardcore sterio you could even go to a lightweight alternator underdrive pulley.

After this it gets really expensive the best way is to go for aftermarket lightweight pistons and rods on a shot peened, ballanced and knife edged crank with the whole shooting match blueprinted. but thats kindof several thousand dollars worth of work.

Damn I just bought a new water pump and back housing for $98+$77... I dont use the full crank pulley, and have to take it off to change the cam belt anyway so I might consider getting a lightweight one... and yea I need the alternator, I have an Eclipse head unit, response amps and crossfire and alpine subs so I really go mental when it comes to stereo systems...

Camshafts are the main reason motors stop revving. If you replace them with some fairly hardcore jobbies then that alone will bump the peak power a good 500-600 rpm. Depending how far you want to go you can also do the above mentioned, but camshafts will be the bulk of the increase.

but camshafts will be the bulk of the increase.

Yeah keep thinking that.

Yeah keep thinking that.

amen brother and TC man what company do u work for so i never take my car there EVER lol

Damn I just bought a new water pump and back housing for $98+$77... I dont use the full crank pulley, and have to take it off to change the cam belt anyway so I might consider getting a lightweight one... and yea I need the alternator, I have an Eclipse head unit, response amps and crossfire and alpine subs so I really go mental when it comes to stereo systems...

the water pump is far from nesicary. pm me if you want details of where to get lightweight crank pulleys from. ive been wanting to do it myself and it would be good to see if they do make a large difference.

Tc was halfway right when he said cams will make your motor rev more, the key word there is "MAKE". the mod list I described is a pretty hardcore, expensive and comprehensive list but it lowers the weight of the components and ballances them so the motor doesnt need to be forced to rev, it WANTS TO. and it will hold together to 10k rpm plus if the support systems are up to it.

If you want more revs for a low budget id say start with the crank pulleys, a CAI, good pod & box, flowed TB, headers and catback.

Unfortunately thats the basic mod list for any magna asside from the crank pulley. do them then see how you feel about your cars performance.

I have removed the air conditioning... 20+kg weight reduction!!! And only need a pulley half the size of the one I have on there now, so thats why an aftermarket one would be good.

sooo doing all work myself....

how can i get a 3.5L to rev to 10 grand?

engine rebuild....
lighter pulleys etc.
what else?

it sounds like mass fun:D

Im working on some form of ducting to the bumper, got a good pod, will flow the tb and intake manifold valley... I'll probably leave the runners the same. Headers would be good... there is already 2.5" Cat back... to no muffler at the moment =) But I'll be installing a nice free flowing lukey muffler on the back. I don't want the car to attract attention and have a droning exhaust.

After that I reckon I should just put in 100hp shot of NOS into it... until the block blows up and rebuild on in the meantime. Im sure I can score a wet NOS kit for about a grand? I saw someone in Perth was running NOS in his stock RB30 R31 Skyline and the thing was running 14 second 1/4's down Kwinana. If I worked on improving my bottom end power... then I wouldn't have to run it into such higher rpm and risk blowing crap everywhere! Good theory?

Erm guys TC is right. The camshaft lobes are tuned for a specific rpm. Changing camshafts is the cheapest/easiest way to move the power band higher. A revvy engine will have high degrees of overlap and will have a long duration. If you have a cam that has the power band up high though you will sacrifice torque down in the lower rev ranges due to high levels of exhaust gas recirculation and blow back due to the large amount of overlap. The stock cams are designed so that they have a decent idle and have plenty of torque down low. Therefore they have low levels of valve overlap and shorter duration.

Unless you have variable vale timing and a variable inlet manifold your engine will be designed for a specific rpm. ie it makes max torque at a certain rpm.

Erm guys TC is right.
Who would have thought the years of engine development I have done isn't just Charade specific :badgrin: :P

Upgrading camshafts will make the engines peak rpm and peak power/torque higher. A standard bottom end and the rest of the engine would easily be able to deal with an extra 1000rpm.

NA cars are hard to make power with, you either need more VE, or more RPM. VE can only be increased very mildly, and arguably, intake mods and pods dont increase it. RPM is how to make a NA car faster.

I'll throw my 2cents worth in just cuz i can...

for the revs thing... the basic way to improve a motors ability to rev is make everything lighter and make it flow better, so in essence every1's correct... porting/honing will increase the ablity to flow air... but ur gonna need properly designed camshaft to allow it in and out efficiently. this is complemented by well designed manifolds and headers/extractors. all of this is a compromise tho... u can build for huge high-rpm flow, but u gonna have a torqueless wonder down low, build for low down torque and its not gonna be able to rev properly

by using lighter weight pistons, rods, crank, properly sized bearings and rings... it will reduce the power the motor has to use to move its internal parts... allowing it to rev free-er.

lightweight flywheel and lightweight/underdrive pulleys will reduce parasitic losses... but on a 9000rpm racing v8 guys get approx 10hp... u can decided if u think its worth it on a street car.

as for nitrous.... its great.... within reason. u have to have it tuned properly or ur gonna make a mess, but for a bit of extra poke at the track its cheap and easy (compared to other methods). i think there is a couple of members using it (1 for sure, so i'll leave more detailed stuff to him if he wants to add)

if ur interested in that type of info... go to ur newsagent and get copies of Engine Masters and Circle Track magazines. they are pretty much all about USDM v8s (chevys, fords, chryslers, pontiacs, etc) but the articles are incredible detailed, and easy to read and relate to any engine. they must know what their doing to build 850hp carby-fed NA that can rev to 9000rpm reliably.

well thats my POV.

Tim

Of course that's if you want to make your engine spin to 7500rpm instead of 6000rpm. If you just want to stop it suffocating at the top of its range, any breathing mods are good, intake or exhaust.


Its called blue printing and Balancing..:P Im doing it..:P

After a camshaft, and a tuned inlet manifold/plenum and exhaust, would probably be to fit lighter pistons and get everything balanced. In my opinion hyperutectic pistons are better than forged, as they will handle just as much stress, but as they're a casting can be made a lot lighter. Shot peened or forged H-beam conrods for reliability would be a good idea. Then get the whole lot balanced.

As said above, parasitic drag really isn't a limiting factor, but if you want to get rid of a lot of it, remove the aircon and power steering. Although I don't think this would make a massive difference unless the cams and inlet/exhaust manifolds had been tuned for higher rpm.

lightweight flywheel and lightweight/underdrive pulleys will reduce parasitic losses... but on a 9000rpm racing v8 guys get approx 10hp... u can decided if u think its worth it on a street car.

yeah they might gain 10hp at peak, but i bet they get there a whole bunch faster than someone with 10 extra hp and all that extra weight...

Underdrive pulleys can cause problems with the alternator not charging properly and things like that. So if you have an underdrive pulley you have to make up for it somewhere else.

I know www.3sxperformance.com does billet aluminium crank pulleys that are the stock size, they weigh less than 1/2 of the weight of the stock ones, iirc. I have no idea of cost...but they're worth a look in. It's something I'm looking at for the DOHC, and I'm pretty sure the SOHC's have the same pulley.

Oh, also I've bought stuff from them before...excellent company to deal with.

Underdrive pulleys can cause problems with the alternator not charging properly and things like that. So if you have an underdrive pulley you have to make up for it somewhere else.

I know www.3sxperformance.com does billet aluminium crank pulleys that are the stock size, they weigh less than 1/2 of the weight of the stock ones, iirc. I have no idea of cost...but they're worth a look in. It's something I'm looking at for the DOHC, and I'm pretty sure the SOHC's have the same pulley.

Oh, also I've bought stuff from them before...excellent company to deal with.

I've just had an underdrive pulley added to the lancer. is about 30% smaller than regular, and weighs about 300-400g (compared to the stock harmonic balancer at over 5kg!!), and i havent had any problems so far with the charging system. I have a voltmeter in car, and it appears to be charging at the same rate. As for revability :badgrin: she pulls like a ***** from 5000 to 6500 lol best mod for price . . . but it will cause the engine to wear slightly faster.

I've just had an underdrive pulley added to the lancer. is about 30% smaller than regular, and weighs about 300-400g (compared to the stock harmonic balancer at over 5kg!!), and i havent had any problems so far with the charging system. I have a voltmeter in car, and it appears to be charging at the same rate. As for revability :badgrin: she pulls like a ***** from 5000 to 6500 lol best mod for price . . . but it will cause the engine to wear slightly faster.

Fair enough mate I'm glad you haven't had problems. On the 3si forums I've read heaps of threads of people having problems, and about half as many with no drama's at all :) Just thought I'd give fair warning.

I am running alot of stereo equipment in my car... it will have at least two subs and three amps, head unit and speakers in the dash, front and rear doors and parcel shelf... so the alternator and battery is a must. Thanks for the link Killbilly, I was there last night checking it out and it seems like a good thing, but for $200 you have to weigh up the costs of it and the effectiveness of it... it's not like im building a race car and have to fully work everything, I'd rather spend the money on something else but I will definately keep it under great consideration as I have to remove mine to install the new cam belt.