304 Power Curve

[Grim304]

Hi People
I have been a recent convert to the ECU world of the humble 304 V8

I ran it up on a $11C and the results are promising but I want more.
I have realised that my current 2.5" exhaust is to small and this was confirmed by others I asked, so have costed up a Mandrel system for about NZ$1k fitted.
It may be a while before I get this now but this has given me some hope that my original aim of well over 300hp could be achievable with more additions.
All this will be documented via the same Dyno.

This shows the final run after taking some of the excess fuel out and shows the AFR in the graph at the end of the video, approx a 7.5kW gain throught the rev range but also the HP ran very flat over 4500rpm possibly because of the exhaust restriction.

Now the question is how much gain can I get?
And what else to do, I have my list of ideas which I believe I have right but want to document each change.

[youtube]http://www.youtube.com/watch?v=kFhxhzCcqys[/youtube]

[Jayme]

exactly what has been done to this motor? does it have the cast headers or 4 into 1 tube headers? have you touched the timing yet? what timing are you running at WOT?

[Grim304]

exactly what has been done to this motor? does it have the cast headers or 4 into 1 tube headers? have you touched the timing yet? what timing are you running at WOT?

I just did a recorded run so you can see.
I have had the heads cleaned up and bigger inlets.
Rebuilt the engine with original pistons and bore size and added an H70 Cam with reasonable lift on stock flat tappets.
Compression has been raised to around 9.3:1

1Valve-1.jpg

[delcowizzid]

we are running one stock rebuilt 304 with tidied up heads under the valveseats,valvesprings and kelfords [email protected] cam 24lb bluetop injectors.its got factory 4 into 1's with new collectors and the ends of the primaries fixed so they are round LOL and twin 2.5" with old superturbo mufflers each side.before fitting the balance pipe we were feeding it around 300hp worth of fuel, injectors are allready over 80%DC .hasnt been driven since fitting the balance pipe.we are getting vacuam at WOT so the TB is to small as well

[Grim304]

Hi DW
Is that 224 duration?
If yes, this sounds similar and gives me hope I will reach my goal with some tweaks and new exhaust.

You say pushing 300hp of fuel, was it on a Dyno?
I have stock injectors and they were only running at 84% DC when it was running a bit rich, I guess uncorking the exhaust might change that

What compression are you running in yours?

[Holden202T]

if this is naturally aspirated you want to aim for 10-10.5 compression, that will help to no end!

my mates carby 304 made 328hp at the wheels on 10.5 comp, crane 286 cam, and just light porting job on the heads!

[Grim304]

if this is naturally aspirated you want to aim for 10-10.5 compression, that will help to no end!

my mates carby 304 made 328hp at the wheels on 10.5 comp, crane 286 cam, and just light porting job on the heads!

Very nice work, Yep I know how well compression adds hp but not going to happen at this stage, not till I work out the rest and get used to the tuning, I will get there eventually but I am learning about this little engine as I go and gaining good feedback.
I decided to keep the compression down while I experiment to see what works and to listen to all the help and ideas and will likely weigh up the gain vs cost, the same as I did with my 202, it wasn't done in one single step but many small ones and the main difference is that the 202 never saw a Dyno as I used the strip as my dyno.
The next step will be a nice single but I would like to here any other advise.

Can I ask was that with flat tappets and stock spark and auto, wondering what else was done, can I get 10:1 on standard bore and standard pistons?

[immortality]

To get 10:1 CR you really need to fit flat top pistons. You can skim the shit out of the heads and get close but the heads are going to get real thin.

[Holden202T]

yeah this was with flat tops, you deck the heads to much and the valley wont line up either!

yeah his motor was flat tappet, t400 tranny and spark was from MSD so not sure.

[delcowizzid]

we shaved the heads as far as we could get away with and still be able to bolt on an unmachined set of bananas.its not been on the dyno yet but will end up there after a bit more tuning and running in.we have plenty more spark to go as even at 14:1 full throttle air fuel ratio it never pinged.