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TwistedTerror
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4,013 Posts
Discussion Starter #1
Im just looking for your guys opinions on making my car little bit faster, I believe it is not going what it should. Here is what I have:

78' Cutlass, est 3400 atleast with driver. Caged, 12 bolt with 4:56 gears, 29X10 slicks, -3 pinion angle, 90/10 front and 50/50 rear shocks w/trick spring all the way around.

388 (4.030X3.800) 6" scat rods, forged crank, forged pistons (12.8.1 compression) has .022/.028 ring gap. Want to run 100-150 shot later on

Brodix 221cc heads ported to 1207 with strip dominator ported to 1207 as well with 2 circuit 1050 dominator on top (jetted 84/92)

Crane roller .670/.625 with 4/7-2/3 swap. Crane 1.5 rockers/girdles and comp cams .200+ pushrods 5/16.

TH350 with brake, 5500-5800 converter 8".

OK, first pass was 11.97 @ 110 with 38 degrees timing. 4 Passes later at 30 degrees total timing it went 11.57 @ 115, 1.57 60ft. Shifting at the time 7k. I believe it should be faster, let me hear any suggestions, thanks
 

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1,035 Posts
I see several things that are raising a flag.
Was the compression actually measured or are you using published specs ?
What is the duration @.050 on the cam?
The C firing order,LS style,which is what you have usually doesn't work well until you change the header tube pairing at the collector,which means a custom header. If you want more info on this call Stahl Headers and speak to Jere,he did alot of testing on this.
What are the spring pressures ?
The 5/16 pushrods are insufficient for a solid roller with high spring pressures.
There is no mention of your fuel system,what does that consist of ?
The large spread on the jetting doesn't seem right unless for some reason you are running a power valve in the primaries.
 

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TwistedTerror
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4,013 Posts
Discussion Starter #4
The compression is counting for the 67cc chambers and everything, which is the calculated compression. I have rear power valve blocked off. Running holley blue pump, 6an braided hose @ 7 psi.
 

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TwistedTerror
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4,013 Posts
Discussion Starter #5
@ .050 the duration is .260/.268
 

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TwistedTerror
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4,013 Posts
Discussion Starter #6
Headers are hooker super comp 1 3/4" and 3" collector. ET times above are using no mufflers
 

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TwistedTerror
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4,013 Posts
Discussion Starter #8
Cant find 11.57 ticket but found a 11.61 pass.

1.5772 60ft
6.8873 et @ 594ft
7.3700 1/8 et
93.21 1/8 mph
11.61 @ 114.84

I barely retarded timing after this pass and went 11.57 @ 115, with same 60ft and 1/8 time
 

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Bracket racer
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13,292 Posts
There's something wrong somewhere that's for sure.....I'd start with WAY too much carburetor.
 

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TwistedTerror
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4,013 Posts
Discussion Starter #11
What carb do you guys think? I tried a 850 ultra hp and slowed down 3 tenths. Pro systems suggested 1000 cfm 4150
 

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Bracket racer
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13,292 Posts
So you pulled 8 degrees of timing out and it went 4 tenths faster.....and this is a 23 degree engine!? I find that hard to believe....are you sure the camshaft is installed correctly and not stupid advanced? Also, what fuel are you using?
 

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TwistedTerror
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4,013 Posts
Discussion Starter #13
It was at 30 degrees when it went 11.57, cam installed dot to dot. The 850 liked 36 degrees
 

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TwistedTerror
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4,013 Posts
Discussion Starter #14
Cam2 when it went 11.57 but last night turbo blue, they switched gas at the place i get it from
 

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TwistedTerror
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4,013 Posts
Discussion Starter #15
It went 11.57 at 30 degrees. And cam is dot to dot. Running turbo blue
 

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Putting the marks on the gears dot to dot means nothing,that cam could be installed anywhere. I have seen some sets 9* off when lining up the marks. If you didn't put a degree wheel on it then you should start with that,until you know where the cam is installed at you are wasting time and money.This is why it is worth it to spend a few dollars more and have an engine dynoed,just because you think you threw good parts at it doesn't mean that they work well together and the thing is making the power it should be.
 

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TwistedTerror
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4,013 Posts
Discussion Starter #18
What should this thing run in your guys opinion? On motor then on 150 shot?
 

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Butch
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8,208 Posts
Im just looking for your guys opinions on making my car little bit faster, I believe it is not going what it should. Here is what I have:

78' Cutlass, est 3400 atleast with driver. Caged, 12 bolt with 4:56 gears, 29X10 slicks, -3 pinion angle, 90/10 front and 50/50 rear shocks w/trick spring all the way around.

388 (4.030X3.800) 6" scat rods, forged crank, forged pistons (12.8.1 compression) has .022/.028 ring gap. Want to run 100-150 shot later on

Brodix 221cc heads ported to 1207 with strip dominator ported to 1207 as well with 2 circuit 1050 dominator on top (jetted 84/92)

Crane roller .670/.625 with 4/7-2/3 swap. Crane 1.5 rockers/girdles and comp cams .200+ pushrods 5/16.

TH350 with brake, 5500-5800 converter 8".

OK, first pass was 11.97 @ 110 with 38 degrees timing. 4 Passes later at 30 degrees total timing it went 11.57 @ 115, 1.57 60ft. Shifting at the time 7k. I believe it should be faster, let me hear any suggestions, thanks
Its no where near 12.8:1 IMO

1) It is no where near 12.8:1

2) 30° timing is way too low, I know you say it runs faster with the 1050cfm carburetor, but as I have said many times YOUR engine needs no less than 36°, the reason your running with the timing so far retarded is, your going lean because you can't pull enough airspeed at RPM through the venturi thus running lean, so in order to run faster/burn the fuel you have without a virtual melt down you have to retard the timing because there is not enough airspeed/velocity through the carburetor to pull the fuel

3) Your fuel pressure is too high, the bigger the needle and seat area the less fuel pressure it can stand

4) You ran those ET's with parts of the transmission stuck to the magnet in the pan, so you don't know if you were getting everything out of it or not

5) Your stall was for a 355, your bigger 383 is gonna make it stall higher, so it was 5800rpm with your 355. I bet its 6500rpm with the 383 costing you all kinds of MPH on the top end due to slippage

6) Don't jet for idle and cruise, ALWAYS JET FOR FASTEST MPH

7) I sent you that camshaft with specific instructions for 260 seat and 680 open, your springs are 225 seat and 575 open, I bet your valve tips have a star pattern from valve train separation.

8) That intake was big enough "AS CAST", plus you ported it not knowing if the porting helped or hurt it, thus the reason I suggested a Victor Jr for your application

You have a couple runs, NO ENGINE combo makes its best pass in a couple runs, more like 35+ runs to get them dialed in changing one thing at a time
 

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Butch
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8,208 Posts
There's something wrong somewhere that's for sure.....I'd start with WAY too much carburetor.
BINGO, I offered to send a 1.401" Venturi carburetor with a 1.6875" butterfly for him to try

A Vacuum secondary would out run that 1050cfm. That camshaft has made just over 600hp with as cast Dart 215cc Pro 1's and right at 600hp with Dart 215 Iron Eagle's

If the camshaft were too big, the 60' would be total shit, but he problem is after the "shooter" shot of fuel its dead lean, thus needing him to back the timing down so low,,,
 
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