Basic V8 engine mods - help (experience) appreciated

[Mopar]

Hi guys, I know it's almost un-Australian to admit this, but I'm not a Holden guy! :hiding:

I'm into Valiants, do all my own work, and own a quick V8 Charger. I know my way around engines, just not V8 Holdens.

That said, my mate has a beautifully stock black VR Commodore S ute with a 304. He wants to liven it up a bit - keeping it completely stock looking - and so I'm going to help him get started. I've read a few threads on here, but don't have time to search for everything.

Firstly, can someone point me in the right direction to finding info on stock 304 injected engines so I know exactly what I'm dealing with: comp ratio, cam specs (flat tappet or roller?), ecu, injection and ignition etc.

For example, the engine has a dizzy - not coil packs - so does the ecu control the timing as well as the ignition and can both be remapped or not? If not, do we need a plug-in chip or can the stock ecu be reflashed?

We're going to start with new dizzy cap, rotor, coil, leads and plugs. OEM or are there better suggestions? Best plugs/gaps for these engines? Best coil?

Is there a good after-market snorkel for the VR, or would something from another model fit? The air intake/snorkel is tiny on this engine. We'll be running a K&N filter and stock TB. Prefer to leave it looking stock.

Injectors: the engine has 150,000km - are there good, cheap replacement injectors for VR 304s? I read somewhere about using VT injectors - what size/colour for a basically stock, tuned 304?

Once the ignition and intake are taken care of, we'll be upgrading to a 3" single exhaust, hi-flow cats and likely Pacemaker headers (other suggestions?).

And once all THAT is done, it will be time for a tune. Good tuners in Perth?

Eventually we'll be pulling the heads to clean them up, replace the valves, springs, seals etc, and may then upgrade to a a small flat-tappet hydraulic cam. But that's down the track.

The idea is to freshen the ignition and get the engine breathing better to improve power and economy, but leave the car looking stock. This is a work ute, so any head work/cam/compression changes will be aimed at keeping her streetable but snappy.

Any other ideas on how to improve the engine that haven't been mentioned?

Thanks for helping a Mopar guy! (But you'll really be helping another Holden fanatic.)

 

[someguy360]

More than happy to help a fellow mopar enthusiast.

Can help you with some of the questions:

comp ratio, cam specs (flat tappet or roller?), ecu, injection and ignition etc.

Stock comp is 8.5;1, the VN-VS 304's were flat tappet (only the S3 VS and VT were roller), and the ignition setup is a traditional dizzy + single coil setup. (The base timing is set with a timing light at 10 degrees BTDC but the advance etc from then on is all controlled by the ECU)


Is there a good after-market snorkel for the VR, or would something from another model fit? The air intake/snorkel is tiny on this engine. We'll be running a K&N filter and stock TB. Prefer to leave it looking stock.

The MACE Engineering cold air intake does a surprisingly good job for a reasonable price, a lot of people on this forum swear by them (google mace engineering)


Injectors: the engine has 150,000km - are there good, cheap replacement injectors for VR 304s? I read somewhere about using VT injectors - what size/colour for a basically stock, tuned 304?

I would just get the genuine VDO direct replacement injectors from a reputable store (be careful with ebay, there are alot of fakes out there that cause all sorts of destruction)
Sometimes it's even cheaper to take them to a specialist and get them reco'd

we'll be upgrading to a 3" single exhaust, hi-flow cats and likely Pacemaker headers (other suggestions?).

In my opinion that sounds perfect, I much prefer the sound of a single system on a 304 over a twin, I think twins are more suited to LS1's etc in later models, I love my single 2.5

You can PM Not_an_abba_fan on the forum and he can do an exhaust shipped to your door (that's what I did, his manta systems have a beautiful note), but being in perth you can probably pick up locally from him or get it fitted too which is an upside


Eventually we'll be pulling the heads to clean them up, replace the valves, springs, seals etc, and may then upgrade to a a small flat-tappet hydraulic cam. But that's down the track.


If your planning on getting it tuned, wait until you do this as you will need a tune to suit the cam change etc (a full dyno tune will set you back anywhere from $600-1500 depending on the tuner, so no point paying twice.)


Any other ideas on how to improve the engine that haven't been mentioned?

If you go a baby cam you can get away with just skimming the heads etc to raise the compression a bit to keep it responsive (also replace the valve springs), if you are going a decent cam then it's best to go flat top pistons, head work and replacing the intake manifold, the factory manifolds are restrictive even on a stock motor......Best to go for something like a Torque Power manifold and a Edelbrock 4bbl throttle body (this is my personally fav combination)



Hope this helps, if there is anything else I can help you with feel free to PM me

 

[someguy360]

edit: double post, whoops

 

[tim_pato]

You can buy memcals or get yours remapped, the run of the mill engines had 165kw the hsv's had 180 and 185 in the vs I'm not sure whether the vr had the knock sensor? To fit one in my vr ss I had to change to a vs starter to fit the sensor unless the vr hsv's had the sensor on the other side? Can someone please clarify? these motors are pretty detuned, you can buy off the shelf memcals (chips) to up the ponys .I've heard good things about mace engineering.

 

[someguy360]

You can buy memcals or get yours remapped, the run of the mill engines had 165kw the hsv's had 180 and 185 in the vs I'm not sure whether the vr had the knock sensor? To fit one in my vr ss I had to change to a vs starter to fit the sensor unless the vr hsv's had the sensor on the other side? Can someone please clarify? these motors are pretty detuned, you can buy off the shelf memcals (chips) to up the ponys .I've heard good things about mace engineering.

The knock sensors were fitted to the HSV motors, standard ones didn't have them.

While the MACE tunes (and other mail order tunes, except eBay tunes, get one of them if you want to see some engine fireworks lol) are good, a dyno tune is ideally what you want.

And for the OP a dyno tune will be a better option, if he is camming the engine it will need a custom tune anyways, something that can not be done very well mail order.


You don't have to change starters for a knock sensor, you just need the knock sensors (there is one on either side of the motor) and the loom for to the ECU and an HSV memcal (knock sensors won't work on the standard or mail order tunes, its only the HSV tunes that had them enabled by default)

 

[wraith]

There is already a thread on things to do to the old 5 litres. Refer to my signature.

 

[tim_pato]

For a cheap intake upgrade go to a vs air intake and cai

 

[wraith]

Let's make this really simple.

You can get mail order tunes on cammed cars. I know because I have one. We have a knock sensor but it's disabled in the tune but we run BP Ultimate so doubt we will have issues. Not worth the hassle really if you don't have it.

The over the radiator CAI is useless.

You can run a Mace CAI but at around $250 cost vs gain is negligible. Although it's a great bit of kit.

 

[tim_pato]

I had to change the starter motor in mine, truly I could not Get the knock sensor in the starter was that long.

 

[someguy360]

I had to change the starter motor in mine, truly I could not Get the knock sensor in the starter was that long.

Strange, I have never heard of anyone needing to do it, unless you had an aftermarket starter that was oversized or something