49 replies to this topic

[LXCHEV]

bones - Wow, very impressive mate. So close to running a 10sec pass too! Couple of questions if you don't mind me asking (I'm real interested in your combo, as I'm also running a 383 Chev): what intake manifold are you using? dual or single plane? Cam - solid or hydraulic, big or small?? Also curious as to what kind of hi-stall you have? Oh, and lastly - extractors? Tri-Y's or 4-into-1's?? Is your engine a big revver or not? I find that 383's tend to fall over after 6000rpm. How driveable is yours? A flat 11 is FAST! Your combo sounds quite tame. My car is a couple hundred kilo's heavier than yours, but a lot of the other stuff is very similar.

myss427 - beautiful work! I rate your car up there with Howard's SLR8000. Awesome stuff!!

I'll post up my combo when I get the time too....

Cheers

[Tiny]

Thanks Wombat! Great stuff

[LXCHEV]

Cheers bones! Our combo's are so similar it's not funny! Yet I'm no where near running the numbers you have. Mine is 10:1 comp. Edelbrock RPM Air-Gap dual-plane. I did have a hydraulic - pretty much identical to the specs you listed (242 and 0.518). Iron Pro Lightning heads, 3200 hi-stall and 3.7's with a 26" tall tyre. Also runs solely on pump fuel (Mobil 8000). Ran 11.77 @ 115mph.

Now I have a solid cam, up around the 260 duration @ 0.050 now, also a bit more lift, and a tiny bit more head work. Was hoping to get right down into the 11's, yet best time so far with this combo is 11.91 @ 114mph. I seem to cross the finish line at around 6000, maybe I should go for some shorter gears.

Can anyone tell me what is the general rule of thumb for rpm over the finish line? Are you meant to cross at peak power? Or higher? Thoughts?

One more question bones - what spark plugs are you running? 6's or 7's and what kinda gaps? I've always run 7's in my chev, but have recently started playing with 6's. Big thanks!

[LXCHEV]

Ok thought I should do this properly, here is my combo:

LXCHEV

Car: LX Torana sedan

Weight: 1480kg's with me in it

ORIGINAL SETUP

Engine: 383 SBChev, 2-bolt 350 block + .030" with ARP stud kit, 400 crank (3.75" stroke).
6" Chev I beam conrods.
Keith Black Hypereutectic pistons. 10:1 compression.
Hydraulic cam - 241 @ .050, .516 total lift.
Iron Pro Lightning heads (200cc intake runners). 2.02 & 1.60 valves. Yella Terra 1.6 ratio roller rockers. 7/16" Screw-in studs and guide plates.
Edelbrock RPM Air-Gap dual-plane manifold (port-matched). Barry Grant 825 Mighty Demon.
ICE Compu-Curve digital ignition system & rev-limiter. ICE 2000 series leads.
Romac Steel balancer.

Exhaust: Custom made 4-into-1's (1-7/8 into 3"). Twin 3" straight-through system, balance pipe, dumped at diff sounded ACE.

Fuel Delivery: Brown Davis droptank with built-in 1/2" pickup and swirlpot. Carter electric fuel pump, 1/2" fuel line to Holley reg, twin feeds into carby. Runs on Mobil 8000 premium unleaded pump fuel (Never tried anything else).

Trans: TH350, heavy-duty clutches etc. 3200 hi-stall. Megashifter (standard shift).

Diff: Ford 9" 3.7:1 mini spool. 28 spline standard Holden axles.

Wheels/Tyres: Convo Pro's - 15 x 4 & 15 x 8.5's. 165 Hankooks & 275/50 MT ET Street Radials (26" tall).

Suspension: Pedders Sports Ryder shocks all corners. A9X-Spec King Springs front, Pedders lowered rear springs. Boxed trailing arms. Rubber bushes through-out.

Performance: 11.77 @ 115mph. Calder Park, cold night, perfect traction.


NEW SETUP AFTER RECENT CHANGES
Same as above, with following changes:
Engine freshened up, taken to 0.035". SRP forged pistons.
Solid cam (flat tappet), 251/254 dur @ .050, 0.544/0.563 total lift.
High volume oil pump. Oil restrictors.
Custom Tri-Y's - 1-3/4" prim -> 2" sec -> 2-1/2" coll. Twin 2-1/2" straight-through system with balance pipe.

Performance: 11.91 @ 114mph. Heathcote, pretty warm day, perfect traction. My best 60ft times are high 1.6's, with both my old and current setup.

Something is holding me back!

Cheers.

Edited by LXCHEV, 14 April 2006 - 11:41 PM.

[Struggler]

I have heard that 100kgs is around 0.25 of a second.

That is about right. For cars running 10-15 sec quarters 100 lbs is about 1 tenth and 1 MPH.

When I removed my 200kg tray from my Tonner I picked up 4 tenths and 4 MPH.

1 Kg is 2.205lbs.

Can anyone tell me what is the general rule of thumb for rpm over the finish line? Are you meant to cross at peak power? Or higher? Thoughts?

For best ET try to cross the finish line at about 300 rpm over peak power.

If you watch some vehicles they will be on the shift light from half track !!! This makes for a great ET with comparatively low MPH, very hard on valvetrain though.

Edited by Struggler, 15 April 2006 - 08:06 AM.

[Struggler]

Have been busy knocking up a new combo after my old 350 reringer got a bit too loose.

Now using a 040 over 400 block with my old 350 crank for 377 CID
Sportsman II heads ported at home, Lunati solid (249,254 @ 050), KB flat tops .005 down from the deck. Victor Jnr and my old 750 vac top it off. Some Pacemaker 1 3/4" 4:1s hang off the side. Same convertor etc as before. Got it together and ran the cam in at home, on to the trailer and straight to the dyno to check mixtures and bed in rings (car is unreg atm). After some minor jetting changes it rattled off 262RwKw with an aircleaner and thru the mufflers. I couldn't believe it.

Last night I took it to WSID and got 2 passes in, 11.6 and 11.5 @ 118. Very happy with it. It really could use a looser convertor now and I have some other things that might squeeze another tenth or two out of it yet.

If anyone is interested I could maybe post some in the build pics.

[TerrA LX]

^^ saves paying for a stroker crank.

[Struggler]

The 400 block has a larger bore, 4.125" as opposed to 4.000 for the 350.
A larger bore is handy for unshrouding valves and improving the bore to stroke ratio.
As ALX76 said, it got me some more cubes without having to buy a new crank, and the 400 block was gathering dust.

Also FWIW the 308/355 combo I posted a while ago went 11.20 @ 119 in the VK Calais last week. Only change was a new fuel pump and a bonnet scoop.

Like you said, its all in the combination. If you get all the details right the rest will take care of itself.

[TerrA LX]

^ yes, and more pressure will give less traction with slicks and the opposite for street radials.

[Struggler]

Like you said, its all in the combination. If you get all the details right the rest will take care of itself.

What are those important details to get right in your opinon?

I was fairly disappointed when my 308/333 only made 200rwkw with what I thought was a reasonable combination. I'm nothing close to being made of money, but I might be able to make some modifications in key, big gain, areas.

200rwkw isn't too bad, depending on the dyno, trans, converter etc that could be a real grunter.
My old engine that ran up to 11.8 only made just on 200 rwkw, it was only minor changes that took it from low 13's to high 11's (jetting, timing, converter and chassis changes).
Take it to the strip and see what it runs, then start your development program.

[TerrA LX]

^ you picked up 2 seconds from fine tuning things, well done.

Edited by ALX76, 29 September 2006 - 11:31 PM.

[Struggler]

^ you picked up 2 seconds from fine tuning things, well done.

Like I said it was more than fine tuning.......

............it was only minor changes that took it from low 13's to high 11's (jetting, timing, converter and chassis changes).....

The actual engine didn't get changed, just the stuff around it.

And 13.3 to 11.8 is only a sec and a half !!

[Struggler]

Hi LXXX, great combo and good work.

Personally I reckon the 3 speed ate your MPH, not the converter.

Let us know next time your at WSID, and say hello.

[Struggler]

Thanks Struggler,
With your timeslips your 11.534 @118mph is almost identical to my 11.611 @116mph, (I haven't posted it yet) What converter did you run that night? and what did you change too when you ran 11.0??

The 11.5 was run with my old converter, about 3800rpm.

The next week was run with a mystery stall (Dominello, was supposed to be 4500 but my combo pushes it closer to 5K) and netted 11.1's.

For the next week I fitted 1.6 rocker arms on the intake only, got 11.0's.

Now sitting at home wondering if I should fit a cage (got worded up by ANDRA officials after a string of 11.0's) or buy/build a dedicated racer.

FWIW I always leave from idle, or no more than 1500rpm. This maximises the torque multiplication of your converter. And three speeds always feel faster, and I must say are zippier on the street, but 'glides are almost always faster (MPH) and usually quicker (ET).

[Tiny]

Trust me you wont ( have a cage and keep it for the street)... NSW roll cage laws are now so strict that basically you cant rego or engineer a caged car!!

So it looks like i'll be aiming for 11.0 all me life!

Cheers!