2JZ head porting.

[2JZR31]

A one litre V8 or an eight litre V8?

Unless otherwise quoted, "V8" means American muscle of around 5.7-6.0 litres.

2J - it's not suitable for automotive use, it's basically a deisel scavange pump - but an 8/71 prepped for use as a supercharger could pump enough air for 600-1000hp.

So just good for clearing out the charge, and not good for building boost? I know someone that reckons they are using one on a petrol V8. But their technical knowledge is sus.

[Kaiser]

Unless otherwise quoted, "V8" means American muscle of around 5.7-6.0 litres.



So just good for clearing out the charge, and not good for building boost? I know someone that reckons they are using one on a petrol V8. But their technical knowledge is sus.

I was under the impression that the old GM 6/71 type blower was what a lot of supercharged big block V8's used in the 60's.

http://en.wikipedia.org/wiki/Roots_Type_Supercharger

[2JZR31]

I was pretty sure I had heard of their use as well, though I don't know much about V8's.

[TK]

6/71 & 8/71 scavange pumps are suitable for use as superchargers, but only with much stronger end plates & better bearings - most of the blowers used on cars before 10 years ago were converted deisel stuff, these days they're all new - to hard to get decent housings etc & they are not as good as a blower made for the purpose.
They served well for many, many years tho.
This one is a V8/71 (rather than the usual 8/71) - so the mounting system is not suitable to bolt up to a blower manifold anyway - that's why I got it dirt cheap.

TK

[takai]

Bill: Got figures with Formula Atlantic valves?
When i get around to it i have some FA valves to go in my spare smallport head.

[TK]

I pulled my finger out & dragged out the motor for the flow bench & decided to test it before I sent it out to be rewound - just in case it was ok.
Tripped out the power for the whole building - had to get the landlord out with the key for the main fuse box, my neibours were not impressed - bugger!
I guess it is fucked - thought so.
Rewind time, then I'll find the time to get the sucker going - it's about time I finished it.

Flow testing on the 2J should happen tommorow, hopefully I'l have full results before I knock off for the day.

TK

[jmac]

when top fuel was in it's infancy (lets say directly after they were once again allowed to run nitro at all, it was banned at one stage around the late 50s or early 60s I seem to recall) 6/71s were popular. More becuase they could be had for a song than anything else. Back then average blokes with enough enthusiasm and an almost affordable budget (assuming all were just workers, non of them owned their own business) could run semi competitively in top fuel.

Hell there was even a time when you could run ok with a big block chev and not a hemi.

If anyone wants a _really_ fun read (and has the time) go to:

http://www.draglist.com/hemihunter.htm

There's the history of the dragster, told from the point of view of the dragster itself, then there's more recent (though there hasn't been any for a couple of years now) bunch of articles from one of the owners/crew of the hemi hunter, with interesting stories about drag racing in general back then.

p.s. - thanks for the effort/info you've put in this thread (and all the others too)

[BigMuz]

TK you'll need some fancy pants electronics to let you vary the speed of the motor- otherwise plumb a Y in an dstart the motor with no/little load on the blower. I just sold a 30hp electric motor that you coulda had for 3/5ths of fuck all... Dale has a spare 5 horse I think? :D

[Billzilla]

Bill: Got figures with Formula Atlantic valves?
When i get around to it i have some FA valves to go in my spare smallport head.

No, but (I really shouldn't but anyway ...) here's my best guess for what my new engine will get at 25" ->
Inlet
0.1 - 96
0.2 - 164
0.3 - 200
0.35 - 211
0.4 - 220
0.45 - 224

Ext
0.1 - 89
0.2 - 151
0.3 - 163
0.35 - 168
0.4 - 170
0.45 - 171

It's only a guess but based on a heap of research and a very similar engine built overseas.

[TK]

Muz - bench has a variable vent in the suction tube for exactly that reason - as little load on the motor as possible on fire up, once it's up & spinning you close the vent untill testing vac is achieved (adjustable by a screw thread).
30hp motor eh, that woulda been nice - spin the fucker at 3000rpm & suck a shitload+1 air.

TK

[TK]

Flow testing not complete - 1/2 way there but I gotta go home now - results on monday, guaranteed!

TK

[21OWA]

sounds good TK
looking forward to the results
cheers
Troy

[Ze]

I think we can wait mate

Will be good to see the results.

[TK]

Results are finally in, some unexpected findings.

Tested at 28" on a superflow SF300 bench - these figures can be relied on.

Inlet
Lift Stock Ported improvement
.05 44.6 45 1%
.1 98.3 97 -1.5
.15 138 136 -1.5
.2 172.7 179.4 4
.25 197 215.1 9.2
.3 213.6 241.8 13.2
.35 223 259 16
.4 228.5 265.4 16
.45 234.8 268.2 14

Exhaust
lift Stock Ported improvement
.05 38.3 38.7 1%
.1 72.2 70.3 -2.5
.15 105.5 106.5 1
.2 125.6 132 5
.25 137.2 151.3 10
.3 143.6 167 16.5
.35 147.2 172.8 17.5
.4 150.4 179.2 19
.45 151.3 182.4 20.5

inlet/exhaust ratio
lift stock ported
.05 86% 86%
.1 73.5 72
.15 76 78
.2 73 73.5
.25 69.5 70.5
.3 67 69
.35 66 67
.4 66 67.5
.45 64.5 68


Inlets responded much better than expected, exhausts are about what I was expecting, but, strangely neither responded at low lift - where I expected some gains to be made, not that it matters - after .2" lift the flow takes off on both intake & exhaust - much more than I expected at higher lift.
End result is a fairly decent gain on both intake and exhaust, but because the intakes have responded so well the intake/exhaust ratio has not improved as much as I thought it would.
Flow test also shows that there will be big gains with higher lift cams, stock lift is about .35", going up to .4" lift improves things a whole bunch.

I'd say, on it's own a ported head (well, this ported head anyway) will perform pretty close to a stock head with better cams, or just short of a stock head with BIG cams.
Add cams into the mix & there would be a very substantial improvement over a stock head with the same cams.

Looking at the figures the cams to use (for stock or ported) would have more exhaust duration than inlet, maybe 264/272 or 268/272, or for bigger cams 272/280.

Larger valves on the exhaust side would be a big benefit, not so much on the inlets - the inlets basically flow plenty, the exhausts still struggle to keep up with intake flow, bigger ex valves would help.
There is a couple of areas on the exhausts that could be improved further & would show a decent gain - but there is a steam hole (water jacket) running quite close in that area so I'll err on the side of caution & leave it be - if I had a head I could bandsaw in half to find out how much metal was there it'd be a different story - but the risk is not worth it without that knowledge.

Even though the in/ex ratio has barely moved spool time will still be sustantially quicker due to a good improvement in exhaust flow, the big increase in intake flow will simply mean that the same power can be achieved with less boost, or more power at the same boost.

Now I've just got to finish the rest of the ports & get it all back together.

Cheers
TK

[DaveBxGT]

Nice work mate, good to see a positive result!

Dave