How to run 14 flat in a VN/P 5 litre

[greenfoam]

I thought I'd just write summary of what I learned playing bolt on/bolt off 5 litre performance in the last few years.

Firstly you kinda need an exec or berlina, irs exec's have a traction advantage and a weight and power disadvantage so it works out about the same.

All standard with nothing apart from say a cold intake you can expect to run in the 15.1 to 15.3 range.

With the timing advanced right up to 16-18 base or a new tune you can expect to be running 14.7-14.8, with a 2.5 inch cat back you might make 14.6, the VN-HSV headers at this stage might be worth .1 over the cast headers but the difference isn't much if it's anything at all.

Removing the body deadner, rubber mats and air con will get you down to about 14.3 (9.2 1/8th) this is where it starts to get difficult.

From here diff gears will gain you about a tenth for 3.45s maybe 2 tenths for 3.9s, a twin system with x pipe and long headers aswell at this stage could easily put you into a 13 second 1/4. This is all assuming an auto car on the stock stall, manuals can be quicker or slower depending on who is driving.

FE2 suspension as usual is the gun setup for traction, other springs don't work so well. Fairly basic stuff, there's no rocket science to having a fairly quick stock 5 litre

[immortality]

Nice one Foam.

i totally agree about the springs, when i took the stock springs out of the VN and put in the superlows which sit lower but are a LOT harder traction became worse from a standing start.

same goes for low profile tyres i.e. 17,18,19's over say 15" rims with decent treads

[vsspack]

Good info greenfoam ,
just bought a VN V6 tune off ya on ebay, how fast did the lexcen end up going when u were mucking around with it?
Cheers

[Aaronsbt1]

greem man with all the mods iv done 2 my vn how much do you think it would do down the 1/4 mile? bear in mind it dose have doubble valve springs, had a look yesterday they was there so im guessing the old owner was right when he said i ported and polished, over sized valves and doubble springs. ha! mad aye

[Morton]

Good info greenfoam ,
just bought a VN V6 tune off ya on ebay, how fast did the lexcen end up going when u were mucking around with it?
Cheers

Pretty sure he ducked into the high 6.9x second 0-100 kinda bracket. I always chased that target with my VP Exec, but never quite got there I bet all the roads from greenfoam's house are downhill ^_^

[88GreenVN]

greem man with all the mods iv done 2 my vn how much do you think it would do down the 1/4 mile? bear in mind it dose have doubble valve springs, had a look yesterday they was there so im guessing the old owner was right when he said i ported and polished, over sized valves and doubble springs. ha! mad aye

I think S1 VN's already had double valve springs..

[Morton]

Yes, the inner spring was a dampening spring.

[88GreenVN]

Yes, the inner spring was a dampening spring.

Can you run S1 valve springs in a S2 motor?

[Morton]

I don't see why not - I don't think the cam or lifters changed? And both used cast rockers.

[Blown V6 Hatch]

I think S1 VN's already had double valve springs..

His ride says 5 litre....

[88GreenVN]

His ride says 5 litre....

LOL blind as a bat is me

[Aaronsbt1]

so my december 1990 vn 5L would or wouldnt have doubble value springs?

[Aaronsbt1]

standard???

[Blown V6 Hatch]

No 5 litre has double valve springs from the factory. The only one that may have had doubles would be the VN group A, not sure on that one though.

They do, however, have a damper. Not getting the damper confused with a spring?

[Aaronsbt1]

ok thanks matie,

coldair induction and k&n filter
bocsh super4 plugs
top gun 8mm leads
6 spring clutch
full 3inch hand made system
oversized valves
double valve springs

what do you think my car will do down the 1/4 after i put greenfoams memcal in?

[Morton]

So it's basically a full weight exec 304 with big valves and a cat-back?

I'd say high 14s maybe if it's in good nick.

Also maybe 15.4 for a flat 16. It's hard to know and every car's different.

I ran a 14.6 (I think) with a better mph than someone who ran 14.3 - I had major traction issues on launch. Everyone has a different experience at the track - why not give it a whirl for real sometime

[Aaronsbt1]

exstracters into a full 3inch high flow system hand built by a mate who builds prostock drag cars

[Aaronsbt1]

have you seen my video on you tube morton?

[Morton]

Tri-y style extractors, or 4-1 style? I'd say they're worth a tenth. Apparently the real time is to be gained with a full twin system + x-pipe. Ideal length for headers finishes somewhere around the back of the transmission. If you want to gain some real time, lose a bit of weight and take out the spare

The best exhaust in the world won't make a rocket ship out of a car with dropped compression on two cylinders, or poor tyres, or the wrong springs. You never know what's going to happen until you do it

[Aaronsbt1]

they go 4 into 2 then into a y after the trany, do you no wat i mean?

[Aaronsbt1]

its 3k of system here and if u look at my youtube or heard it in real life i think you would understand

[padrickz88]

Hey jason, what i was wondering.........
If someone was to have a 304 with gears and a stally (lets say 3.7-3.9's with a 3000-3500 stally) Already done for mods planned later down the track....

Obviously with a tune, exhaust, cai etc what sort of 1/4 would you think they would end up running?

Just curious because I think I remember seeing somewhere that someone done a mid 13 with the above set up? (cant remember exactly) possible or no chance?

[greenfoam]

Yep someone ran a 13.9 or at least a 8.9 1/8th in a VQ in fact I think with that setup, was at least a 3500 stall as far as I can remember. A guy in South Australia did it

[padrickz88]

Ok cool just making sure i didnt dream it or something lol, thats a pretty sweet time for jack shit work...

[DeViLisanAnGeL]

I ran 14.5@96 in my VQ with VS Airbox, no OTR or CAI, Std Tune, Cheap dodgy ebay extractors, horrible Y pipe, std cat, off the shelf single 2.5" reback system, open centre 3.9 diff, std stall, rebuilt auto. Full weight with 18's incl stereo, interior etc and on SSSL springs.

i think its crisp-ness was attributable to good maintenance in both oils and ignition.

As jason said, I think i would be able to snatch a 13.9 with ease in a VQ using:
Paceys, twin cats, 3" single system
Good cold air intake
3000rpm stall
3.9 spool diff
good tune