Im going to try something

Went to the Olds, Buick, Caddy event yesterday. I got one (crappy) pass in, 14.06 @ 96mph, first to second auto shift at 6 grand, beautiful, right on the money, rpm climbs again, more and more, more, sounds like I'm hitting a rev limiter, ASSHOLE SHIFT AGAIN! I'm sure I was over 7 grand, wow I screwed that run up:shock:
I try to go again, but weather moved in, plus things back at home cropped up, we leave at 10:30
On the way home, I'm thinking even with my way late shift to third, how much better would my run have been? Even taking into account the weather, warm, muggy, as Larry said.
I'm going to bolt on my Stage 1 intake, and see if my 13's come back, if they come back with a BANG, like I dropped into them with my JW convertor, then the SP3 isn't the right intake for my combo.
My transmission is good to go now thanks to Janis, so is my fuel system, so those variables are eliminated.
Even if I netted a 14.0 at 97 with the SP3, that's still a far cry from my best of 13.65 at almost 99 with the Stage 1.
I'm trying with the SP3, but I think I don't have enough "something" to make it work like its designed too.
So I'm bolting the Stage 1 back on and see what happens

 

Mark,

How many runs do you have on that SP3? If you dont have at least 40 you have not got it tuned properly yet. It may be too much intake but I don't think you've gotten everything out of it yet. Wish we lived closer, I'm sure I could help.

 

Its to bad you weren't able to test a 650 DP carb with your S/P intake like gsjohnny and I advised. o No:

I really think that 850cfm carb is what slowed you down, I think you may of got greedy with the cfm choosing the 850?

Does anyone have a 650 DP that they can loan to Mark to try before he changes intakes?

The long narrow runners of the D/P intake IMO is a choke point to flow a lot of air quickly and kind of self meters how much air gets in tolerating larger cfm carburetors. The S/P not so much and will let much more air in to fast for the size and RPM range your cam wants to spin at hurting your low and mid range torque.

I went to the track when I was having traction problems and I thought well maybe if I disconnect my secondaries I may be able to launch better with less spinning because the engine will make less power but it ended up being the opposite and the tires spun even worse. It would seem I gained a whole lot more low end torque by doing that so the secondary arm was re-installed to kill some low end to help launch without so much spinning. I think that was with the 10 bolt open rear with a 3.36:1 gear, one wheel wonder before the 12 bolt rear with the 3.07:1 gear and posi. Of coarse the MPH were down with only using the primaries and a slower ET but if I could of hooked may of been a better 60 ft time?

So I think the old saying bigger isn't always better may apply in your case.

With the mile high big block like deck height of a sbb 350 makes for a very wide intake for a small block with a D/P with very long and narrow small block sized runners. If you ever tried to breath through a garden hose, the longer the hose the harder it is to breath. Same as the long small block sized runners do, but the side effect is lots of low end torque. The small size for their length runners aren't negatively effected as much as an open plenum S/P runner would be to having to much cfm, restoring the math of choosing a carb based on CID with a S/P.

Anyway that's just my opinion and I may be totally wrong, but a carb swap is much easier than an intake swap and would be worth a try? o No: GL


Derek

 

i have tried numerous carbs with my own s/p and on the supercharger. What carb did i end up using for both....650 dp. The bigger carb would probably be good for a bonneville run, but not the 1/4. The rules for the s/c says you need to a bigger carb. Yeah, right..........right back to the 650.
Don't over compensate because EVERYBODY tells you to use a bigger carb when NONE of them have NO EXPERIENCE with what you have done and what i have done. Theory and practice are not the same.

btw, don't you just love how the 350 rpm reacts to a s/p. it loves the rpm.

 

It sure does love to rpm as I found out!
I'm curious to know what rpm I was at before asshole me shifted, engine sounded great except for the change in tone that sounded like a rev limiter, I'm thinking it was valve float, or the lifters got pissed.

 

WOW, I knew the weather was crap, but under ideal conditions, I'll take a 13.59:Brow:
Soooooooooooo, in other words, I should just chill, and wait for better weather instead of trying to go faster in this hot summer weather?

 

I think about 10 runs maybe so far.
Like Larry was saying the weather is working against me and anybody else running at the track, I just don't know exactly what this thing wants, rpm, fuel, air, HUGE compression, better heads:eek2:
The engine run awesome around town, highway, idling, doesn't load up.
I idle in gear at 800 rpm, out of gear 'bout 900 rpm, throttle response is very sensitive, no hiccups, hesitation, to me its the same as the Stage 1 intake as far as all that goes, I don't understand all the talk about single planes killing your low end, drivability sucks unless you run 3000 rpm or higher, I'm not experiencing any of that.
Ok, I'm going to take your guys advice and keep trying with the SP3 on my combo:TU:

 

Anybody make restrictor plate:Brow:

 

Others here advised on that carb too, myself and Guy included. Seems there may be something to it eh?

FYI for any who didn't know: the Qjets CFM ratings are actually maximum potential with the proper secondary opening angle, and don't give the full CFM rating otherwise.

So everyone who thinks their Buick 350 won't run right unless you have no less than "750 CFM" may be in for a bit of a surprise to learn they're actually only running around 635 or so actual CFM at full throttle on a 350 "750" Qjet.

(178 CFM primaries on the '750' Qjet, 228 CFM primaries on '800' Qjet; 572 CFM potential for secondaries on both. At an 80% opening restriction, gives 457 CFM which results in 635 CFM for the '750' and 685 CFM for the '800')

Makes a 500-600 CFM 2 barrel not seem so small when putting things into perspective and when used with the proper combination. Tall, narrow, and long intake runners accommodate larger throttle blades just fine...and let's not forget the benefit of more even fuel distribution that 2v and square bore carbs afford.

Not trying to knock the Qjet or any other carb choice--just offering up another POV.

 

Do they still rate 2bb carbs at twice the vacuum as 4 bbl carbs?

Jim

 

It would be safe to assume your old combo suffered et wise from the trans starting to let go.
Also I believe you had less converter then as well??
So between fixing the trans, new stall,bigger carb, and the magical fix all intake, your still way down on MPH
There is no air density going to fix this IMO
Just saying

Think about this for a minute,..... Steve's car runs 4 mph quicker through exh manifolds with less motor, and a stock intake!!

 

I believe something is going on with your engine that is holding you back. Your a/f you say is 12.5 wot and 12 cruise? Should it lean up some on cruise with higher vacuum? An open plenum changes vacuum signal. But you should be adle to tune that. Maybe an advance issue?

 

But Steve doesn't have a 200 cfm vacuum leak.:eek2:


In my opinion, I may be wrong but 850 cfm(some even ran 830 cfm) is what nascar use to run on their 358 cid engines that spin 9,000 + RPM with a whole lot of compression to make a very high revving RPM 850 HP or so.

Derek

 

IMHO, you have no where near enough testing time on this combo,now that your trans is healthy.(well sort of)

Get your shifting fixed, and then start correcting all your times back to standard conditions, sea level, to be able to evaluate the combo against itself, run to run on different days with different air condtions... and against changes you make going forward, which will include installing your previous intake, to do the proper A-B-A testing.

JW

 

Hmmmmmmmmmmmmmm..............

 

I believe if more folks screwed their hoods hut, and worked on the rest of the combo they would run faster.
But something here isn t addin up
So if after all this testing with a better converter,fresh trans, new manifold and carb it still runs equal to or no better than a similar car with no headers, less converter,etc then what?????

 

nascar is comparing apples to mud. their engines are built to BREATHE. we are not even close to what they can do/have done. T/A is making parts that are unblocking the flow but we are a long way from the comparison of a nascar engine. AND i don't know of anybody here that is going to spend that much money on a 350 when the 455 has more to offer. i do it because i like the challenge and hopefully the 'banker' never finds out. :grin:

 

Yep, all the ingredients in the recipe have to be compatible.