There seems to be alot of threads lately about how to get power out of your 308. So I thought I would put a few tips up.
Ill focus mainly on the carby V8s but some of this can be adapted to EFI.
First off heres some tips on how to get a bit more out of your beast without spending a bucketload on an engine rebuild.
Obviously give it a service! Oil, leads, plugs etc. They always run better when theyre maintained.
First thing is usually to fit extractors and a nice exhaust system to free up some ponies. This also creates a nice sound which is always a bonus. Alot of people go too big in exhaust size which isnt always a good thing. On a stock 308 a twin 2" or even twin 2.25" system (You may then have a single 2.5 or 3" tail pipe) usually suffices. Unless you're going for a big power / stroker you wont need any bigger. I run a twin 2.25" pipes on mine which is great for torque but I wouldnt mind going to twin 2.5" pipes which would make it a bit louder while compromising lower / mid range power. With some good straight through mufflers you will get a great note and also free up a few hp.
Now that your ride is sounding hot the next thing to do is make sure its getting a good amount of air. The standard filter and snorkel assembly on holdens is fairly restrictive and is mainly there to keep the sucking noise quiet as you can be a little noisy. First thing to do is get rid of the snorkel and get a nice K&N filter (or similar). You can either leave it at this or to further enhance the performance you may wish to fit a VK HDT style air tray or even a bonnet scoop to get that cold air stuffed down its throat rather than sucking in warm engine bay temperatures.
This picture shows a stock set up (On a ford - same principles apply)
Now dont go and ditch that quadrajet for a holley! Theyre a great carby and are similar in size to a 650 holley. Because of the smaller front jets you get great driveability and fuel economy and once the pedal is mashed the secondaries open up and the fuel pours in giving great performance. Its only once you need a bit extra and better tuneability would you ditch your trusty quaddy.
Another way to gain a few more hp is to fit some electric thermo fans from an EL - AU falcon. These are available from radiator places and are great! They can put a small strain on your electrical system so that may need some attention. Otherwise you should have a clutch engaged engine fan. These are good as they pretty much free spin until they cut in. They dont drain a huge amount of power but they can be noisy as they move alot of air. Make sure you have a radiator fan shroud no matter what - otherwise you will always have problems keeping it cool!
If you still have the old points distributor then get rid of it! Theyre nothing but hassles. Upgrade to VK / VL electronic ignition system. They give better power and theres almost no maintenance!
Now that you have those simple tips on getting your motor breathing and sparking well lets look at the other driveline components.
Auto: Most of the standard V8 automatics feel very sluggish off the line because most have a small stall convertor (1900rpm). To give it a bit more poke you could look at installing a 2200-2500rpm convertor to get it going. At this stage you wont need to upgrade too much. Again make sure its got heaps of oil and its well maintained.
Now down to the rear of the car. Most holden V8s have a fairly highway geared rear end from the factory - often a 2.78 or 3.08 ratio. You can change this to give huge down low acceleration, good all round, or low revs at high speed (standard) driving.
You will notice alot of street / drag cars run a 4.11 ratio rear which will give great low down take off but rev fairly high at 100kmh. A good all rounder would be the 3.55 option. Whilst still giving a good take off these gears dont rev too hard at higher speeds. I run the 3.55 ratio with a 4 speed close ratio manual and it sits on about 3000rpm @ 100kmh which I think is good. The auto will sit on similar revs.
So without spending too much you have a great breathing motor making a little bit more power than standard, a nice convertor to aid a good take off and some nice diff gears to get you moving. This is your basic guide to quicken yourself up a little without breaking the bank.
I wont go into modifying the engine / trans too much more as there are alot of variables to consider - your engine shop can go through it depending on your application.
If you were to follow this guide you could possibly see an extra 20-30hp. The main thing you will notice is that your car now hauls! It could possibly be 1-2 seconds faster down the quarter mile.
These are my experiences and by no means gospel.
Feel free to add your thoughts and experiences.
Brett
Some original photos have not been recovered yet.
Bretty, a 3.55 geared 3 spd would rev just under 3k, not 4 spd I'd be fitting a tranny cooler at the same time as the converter too
GREAT THREAD
Some original photos have not been recovered yet.
I have a 4 speed manual though... I was saying it does about 3000rpm @ 100k's.
Yes I forgot, a good transcooler should be had at all stages of performance even from stock standard.
i also had a stage2 shift kit put in my auto makes the shifts hard n fast lol
if i had a 2500 stally would it rev more cruising at 100kph? it sits on 3000rpm at 100kph with a standard stall.
It would sit the same at 100 kays with a small convertor as it will be above the convertor lockup. If you had say a 5000rpm stall then it might sit slightly higher as its not locked up tight and can be a little looser.
^^hahaha
i think you missed the part about fitting a supercharger or ridiculously sized turbo
good write up!
Some original photos have not been recovered yet.
Great write up.
My old 308 VH BT1 made 140RWKW (200000 km old engine) with exactly these type of mods except it had an upgraded coil ($100) and re-curved dizzy.
I'm a big fan of free horse power i.e. electric fans, no power steering/Aircon etc
Quote:
Originally Posted by SRBMUU
what would be a good combo for a gas setup? i.e cam,carb, stall etc on auto of course
Depends on what purpose you are using the vehicle. What do you want from it? The good thing with gas is you can run higher compression due to its higher octane rating. I saw a while ago a guy had a 350 running straight gas and had 12:1 compression for every day driving!!
Quote:
Originally Posted by misk
^^hahaha
i think you missed the part about fitting a supercharger or ridiculously sized turbo
good write up!
Yeah I know! Its supposed to be a very basic thing that most people can do without spending much money at all. Once you get into performance things everyone has thier own opinion about everything and desires different outcomes - so its hard to please the majority!
Quote:
Originally Posted by VLT-025
Great write up.
My old 308 VH BT1 made 140RWKW (200000 km old engine) with exactly these type of mods except it had an upgraded coil ($100) and re-curved dizzy.
I'm a big fan of free horse power i.e. electric fans, no power steering/Aircon etc
Great! Sounds like a fairly tough motor. Mine made 130rwkw with the above mods. Its got high kms too. In a V8 that kind of power is alright as it starts almost from idle.
Some original photos have not been recovered yet.
i use the car daily and towing boat , jetski etc thats why its going on gas. not after insane power just something half decent. maybe down the track stroke it but that would be a long way away.
If you're going to be towing then youll need a small stall convertor. This limits the driveability Vs power. A possible solution would be to fit a blower as they increase torque throughout the rev range and you dont need a large convertor.
Towing and Performance dont generally go hand in hand. A stroker would also be a good idea.
I have a friend who has built a 351 to standard specs but put in a stroker crank bringing it up to 378 cubes. This thing has an insane amount of torque and perfect for towing but also absolutely hammers right up to 6000rpm. He has run mid 13s in it in a manual, 3.55 geared XY falcon. I took it for a spin in the wet and it fish tailed through third gear at 1500rpm! All this and its just his tow car to tow the race car.
Food for thought.
Quote:
Originally Posted by TWO89
Yeah I know! Its supposed to be a very basic thing that most people can do without spending much money at all. Once you get into performance things everyone has thier own opinion about everything and desires different outcomes - so its hard to please the majority!
lol its all good man! was just havn a bit of fun.
i dont think there will ever be a set way of doing mods like that!
a blower? geeez souds like alot of dough :P like i said i do tow but not oftern just in the summer probbaly once twice a week during it. i just drive the car around more so its not really a HUGE issue. what kida blower would be suitable btw
