Lemme

Any idea of quarter mile estimates for that combo wih 2.73s?

oldalaskaman

this would get you quick, which is better than fast at the point you're presently running, in other words it will get you into the powerband quicker and your off the line time will be quicker. best bang for the buck. you will think you've done all those spendy improvements for a lot less money, and if you then do all those improvments , you will already be far enough into the powerband that they will actually work

383vett

SuperRam with a 406. Good to 6500 rpm.

bjankuski

Very good combination.

The superram on a 350 with 219 cam and good heads will run low 12's high 11's all day long.

Lemme

So is the idea to buy the new D36 diff ratio gear and get a diff specialist to swap it over? What ballpark cost would that be?

Lemme

11's sounds good. How does the Hi Stall and the diff gear impact on those times? I have a 2500 hi stall and 2.73s. What is the optimal shift rpm?

I probably need to get myself a shift light / monster tacho.

Beach Bum

As many racers will tell you, there are 2 keys to going fast....

1) Make a bunch of HP

2) Get to where the HP is

You would be increasing your HP with just a Superram upgrade, but you wouldn't be doing anything to get to that HP faster..... hence your timeslip may only have a marginal improvement if any at all. Considering you would have shifted your peaks up in the rpm range, consider also upping the converter and/or gearing a bit too.... then you'll see a worthwhile et improvement with just a Superram install. Any modification you do, you also have to think about where that puts your peaks at as well as your new shift point and then figure out how you're going to get into that final 1800 rpm window as fast as you can. This is the key to happy timeslips.

As a note, its not much more to upgrade your cam while your motor is apart and I always recommend that if you're doing something dramatic such as an intake or cylinder head upgrade. Even if you're an early C4 running a flat tappet cam....upgrade it. You won't regret it.

On another note a 350/AFR/219/Header combination is good for approxmiately 425 HP and roughly around 460 ftlbs of torque if running right.... even a little more with the improvements of cylinder heads nowadays, plus a ported SR might increase that a little bit. Which as stated earlier is good for easy high 11's @ 113-116 mph area and even mid 11's if you're optimizing your short time capability. This is faster than most people have ever experienced and is a reliable wonderful docile street/strip set-up.

good luck with whatever you decide on.

Lemme

Not sure what you mean by the final 1800 rpm window! I have an 84 with a 3.31 ratio so swapping that over will only cost me blood sweat and tears.

Beach Bum

With street cars, your rpm window is typically a little bit larger than dedicated racecars. And is dictated by your slap-back rpm, which is dicated by the cam/heads/weight/gearing/converter/transmission, etc.....

But, for simplicity, if you shift at 6200 rpm (A-typical for a SR/219 combination).....and the rpm it falls back to on after the shift change is 4400 rpm, than thats your working rpm range that your car will see for approxmiately 1310 feet of the 1320 feet of a 1/4 mile jaunt. You want to get to that window as fast as possible.... you have very little HP below it. Once your power is set.... that only ballparks your trap speeds, your et is more based upon your short times. In otherwords, improve that 60 ft time and 330 ft time and you'll see dramatic et improvements, hence you'll be the first guy to the finish line. To do that, you have to get to that rpm window and let your HP, whatever it may be, take over from their.

In a 1/4 mile race, my car never see's below 4400 rpm at any point on the dragstrip.... it flashes above that while I am still in my roll-out.

Lemme

Photos like that really are inspiring. Being the only corvette at the drag meet the other night got me quite a lot of attention. Pity I couldn't deliver on the scoreboard.

I may have to start building one of those 406s as well as making my 350 more powerful.

Lemme

So the missing 10 ft is the launch?

oldalaskaman

these folks are basicly saying the same thing only wording it differently, dont know what your cost would be, havent done one in years....and years. an easier way to think of it would be that at your present gearing you arent using all of your engines horsepower and torque till you get to about 35 mph and you're not getting there till you've traveled about 50 feet. the lower gears{higher numerically} would get you to that level in about 25 feet, so even though your havent changed anything but the gears, you are quicker, which will lower your times. at the other end of this theory, you will max out your rpms quicker and to go faster you will need some of those spendy parts so you can get your engine into the higher rpms without breaking it.. I ran a small block ford years....and years ago with a 5.65 pontiac rear gear setup. super quick off the line , but someone with less gears and more of those spendy high rpm parts could catch me about the last 15 feet. This is a real symplistic way of describing it, But then I'm a simple man.

Beach Bum

That was an estimation based upon your set-up.... you want it to be 0 feet....

If your converter/gearing/engine/weight combination produces a 3000 flash rpm, then for your motor to build rpm to get up into your rpm window will take anywhere from 2 feet to 25 feet depending on where your window is as well as gearing. But, make no mistake about it, the vast majority of your time spent on a 1/4 pass is spent in your rpm window.... once you get in the middle of 1st gear, you're done with low rpm stuff until you get to the return road.

When you add rpm capability (Typically more HP).... you have to also make sure you're getting to that power just as quickly as you used to get to your lower rpm window. In just about every scenario short of adding cubic inches or forced induction, you are trading low rpm torque to get more HP. This means..... get more converter/gear if you want to maintain or improve your short times, hence improved timeslips.

Lemme

You should have been a teacher! What I find interesting is that currently the vehicle did an 1.88s 60' time with 2.73 gears which seems reasonably good looking at the official timeslips. Where I feel I am really faltering is at half track where it just has no go leaving me with only 94 mph. Seems to be getting choked for air. Typical of the TPI I suppose.

So, the plan so far:

1. Diff gear change (2.73 to 3.31 from my 84)
2. Superram and ported accel base
3. AFR 195 heads
4. LPE 219 cam
5. Shift light and monster tacho
6. Maybe a higher stall torque convertor - 2500 to 3500?

oldalaskaman

the shift light and monster tach should add 50-60 hp all by themselves

Beach Bum

As a note, here is a simulation I think I did for Calderone a while ago.... point being you can see in the lower right the run chronology on what is actually happening as you go down the strip.

You'll notice that in this particular simulation the motor is at 3400 rpm as it comes out of its roll-out and is at 4500 rpm by 21 feet out..... and the rpm drops to approxmiately 4400-4500 rpm after each shift.

That 0-20 feet of the dragstrip is the most important of the entire track as far as producing favorable et's.... in this simulation, the converter is too tight.

Its important to know what is happening if you are looking to improve your timeslips.

Lemme

So the vehicle is 12 inches behind the start line in stage? In the simulation the TC is 1800 or 3400?

Lemme

To be honest I hate the things but leaving it in drive and letting it shift when it feels like is probably not going to get me the best out of the vehicle. Unless I can do the manual shifting by instinct of course then I wouldn't need it.

Beach Bum

Yes, that is a shallow stage.... everybody is in the 10-12 inches behind the starting light if you shallow stage, which most do.

Its a running start into the start light... which most are going in that 5-6 mph area by the time they trip the light if they didn't spin.

Converter in that simulation is 3400 rpm flash (Along the lines of a 2600-3000 rpm rated stall)..... 1800 rpm is merely the footbraked rpm.

Lemme

Time to buy those heads and cam. In the meantime I can swap the diffs over.

Nothing like having a plan that you are confident will work.

Thanks heaps everybody.