Ok lets talk 12 sec. cars.
04-16-2003, 10:25 PM
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Ok lets talk 12 sec. cars.
How are you guys getting in the 12's. I've built quite a few cars and heres a pretty good guide to what it has taken to get bottom to mid 12's in the quarter. Lets hear about some other budget combos.
Engine;
-----------------------------------------------------------------------
350 .030
345Np pistons (don't get the hyper because they sit further in the hole and you lose compression)
274 extreme comp cam
ht817 lifters
Cloyes true roller chain
regular cast rings (seal quicker)
Vortec heads stock except the guide boss milled and 550 lift single springs(although 500 lift are all you really need) installed
Performer RPM Vortec intake
750 4779 Holley (ouch that hurts the budget)
BTW remember these heads are fast burn type and really don't like a lot of timing 32 degrees should be tops total timing.
Trans: (Old school)
350TH B&M shift kit and 3000 converter The Jegs $189 one has been doing just fine!(plus its made by B&M)
Rear:
3:73 Posi (would prefer a Powertraxx everytime but use what you can find as long is its not a gov-loc)
Exhaust:
Headman shorties with a 2 1/2 Y-pipe and a 3 inch cutout for the track. Running a dynamax exhaust keeps it quiet (read no tickets)
and the cutout still isn't that loud at the track compared to most others.
Slicks:
Borrow them or whatever don't even think of street slicks. Why pay 139 a tire and drive it on the street for 3 months and have a bald non-handling tire. When you can buy one set of slicks that will last you for a few years.(Taken care of properly)
This is just a guide that I have used and has been very successful feel free to comment.
Engine;
-----------------------------------------------------------------------
350 .030
345Np pistons (don't get the hyper because they sit further in the hole and you lose compression)
274 extreme comp cam
ht817 lifters
Cloyes true roller chain
regular cast rings (seal quicker)
Vortec heads stock except the guide boss milled and 550 lift single springs(although 500 lift are all you really need) installed
Performer RPM Vortec intake
750 4779 Holley (ouch that hurts the budget)
BTW remember these heads are fast burn type and really don't like a lot of timing 32 degrees should be tops total timing.
Trans: (Old school)
350TH B&M shift kit and 3000 converter The Jegs $189 one has been doing just fine!(plus its made by B&M)
Rear:
3:73 Posi (would prefer a Powertraxx everytime but use what you can find as long is its not a gov-loc)
Exhaust:
Headman shorties with a 2 1/2 Y-pipe and a 3 inch cutout for the track. Running a dynamax exhaust keeps it quiet (read no tickets)
and the cutout still isn't that loud at the track compared to most others.
Slicks:
Borrow them or whatever don't even think of street slicks. Why pay 139 a tire and drive it on the street for 3 months and have a bald non-handling tire. When you can buy one set of slicks that will last you for a few years.(Taken care of properly)
This is just a guide that I have used and has been very successful feel free to comment.
04-17-2003, 11:59 AM
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Car: 1991 Firebird
Engine: 427 LSX
Transmission: Turbo 400
what do you mean about hyper pistons? I assume you speak of ET streets when you speak of "street slicks" I dont see why they would wear faster than regular slicks. And since they are DOT approved you have the option to drive on the street and be prepared at all times. Plus, some people swear that the ET streets hook better than the slicks. Who wants to get caught with non sticky tires or with the nitrous bottle closed?
Also, could you go into detail on your car that ran 11.2.
Also, could you go into detail on your car that ran 11.2.
Last edited by GofasterFirebird; 04-17-2003 at 12:03 PM.
04-17-2003, 12:16 PM
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Car: yy wife, crazy.
Engine: 350, Vortecs, 650DP
Transmission: TH-350
Axle/Gears: 8.5", 3.42
Originally posted by GofasterFirebird
what do you mean about hyper pistons?
what do you mean about hyper pistons?
He's right. The compression height it a little shorter. The cast version advertises 9.5 comp ration with 64cc heads, but the hypers are 9.25 comp ratio with 64 cc heads.
Although it is only .25 of a point, it can make the difference between 299 HP and 300 HP.
I'm not sure why they did that, but I don't make the pistons so.....
Last edited by AJ_92RS; 04-17-2003 at 12:45 PM.
04-17-2003, 12:50 PM
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Car: yy wife, crazy.
Engine: 350, Vortecs, 650DP
Transmission: TH-350
Axle/Gears: 8.5", 3.42
Originally posted by GofasterFirebird
He just made a generalization that all hypers reduce compression.
He just made a generalization that all hypers reduce compression.
That is all I was asking.
He was referring to Speed Pro pistons. I don't know if other manufactures do the same though.
So for sake of argument, and for the general public...... Hypereutectic pistons don't cause a loss in compression because of what they're made from. Speed Pro's do because what I said ealier.
How's that?? :lala:
04-17-2003, 01:07 PM
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Originally posted by GofasterFirebird
what do you mean about hyper pistons? I assume you speak of ET streets when you speak of "street slicks" I dont see why they would wear faster than regular slicks. And since they are DOT approved you have the option to drive on the street and be prepared at all times. Plus, some people swear that the ET streets hook better than the slicks. Who wants to get caught with non sticky tires or with the nitrous bottle closed?
Also, could you go into detail on your car that ran 11.2.
what do you mean about hyper pistons? I assume you speak of ET streets when you speak of "street slicks" I dont see why they would wear faster than regular slicks. And since they are DOT approved you have the option to drive on the street and be prepared at all times. Plus, some people swear that the ET streets hook better than the slicks. Who wants to get caught with non sticky tires or with the nitrous bottle closed?
Also, could you go into detail on your car that ran 11.2.
I won't use them because:
1) They are made harder but that also makes them brittle so if you do push it to hard they scatter.(All my 400's use forged pistons because of the Rod/stroke angle). With the 350 and a6000RPM cieling this has not been a prob. but...
2)The piston sits at least .020 in the hole if you believe this is only
.25 drop in compression you are dreaming.
The car running 11.2 at 119 has a 400SBC,5.7 rods.forged pistons,Afr 210 heads,850 DP,Runs on pump gas,it also has a powertraxx locker and a super street fighter converter in a TH350. It would be EASY to put it in the bottom tens Maybe high nines with N20. I don't see justification in running a street slick on a car that is driven regularly driven. I mean driving Radials like 295/50/15's on the street and 28-10.5's at the strip. If a person were to want to run(which just doesn't happen much) I would simply make a time to be at the track and run for whatever they have in mind.
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04-17-2003, 01:14 PM
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Originally posted by AJ_92RS
A part number is a generalization?
And I answered your question.
He was referring to Speed Pro pistons. I don't know if other manufactures do the same though.
So for sake of argument, and for the general public...... Hypereutectic pistons don't cause a loss in compression because of what they're made from. Speed Pro's do because what I said ealier.
How's that?? :lala:
A part number is a generalization?
And I answered your question.
He was referring to Speed Pro pistons. I don't know if other manufactures do the same though.
So for sake of argument, and for the general public...... Hypereutectic pistons don't cause a loss in compression because of what they're made from. Speed Pro's do because what I said ealier.
How's that?? :lala:
Last edited by flyin89; 04-17-2003 at 01:45 PM.
04-17-2003, 02:09 PM
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Car: yy wife, crazy.
Engine: 350, Vortecs, 650DP
Transmission: TH-350
Axle/Gears: 8.5", 3.42
Originally posted by flyin89
You are correct AJ. Also the Jegs catalog lists the compression ratios as H345 9.35 with 64cc heads and 345np as 10.2 with 64 cc heads. .020 down adds a lot of chamber. You could be losing 20 hp.
You are correct AJ. Also the Jegs catalog lists the compression ratios as H345 9.35 with 64cc heads and 345np as 10.2 with 64 cc heads. .020 down adds a lot of chamber. You could be losing 20 hp.
I have H345CNP30 flat tops and ya know what..... I just did the math and from what I can tell, the total is 9.27" ......
Here's my math so hopefully someone can verify it.
stroke = 3.48
divided by 2 = 1.74
add 5.7" rod length = 7.44
the pistons have a comp. height of 1.83"
add that to the 7.44 = 9.27
Is this right?
You've got me wondering now.
I'm probably doing something wrong. I guess I'll have to actually get them pressed on and installed to measure how far they're in the hole.
04-17-2003, 02:29 PM
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Car: yy wife, crazy.
Engine: 350, Vortecs, 650DP
Transmission: TH-350
Axle/Gears: 8.5", 3.42
Nevermind..... :sillylol:
I just went and actually measured the compression height (I don't know what the 1.83" is...) and it's 1.564"
That puts me at 9.004"
I can breath now.
I just went and actually measured the compression height (I don't know what the 1.83" is...) and it's 1.564"
That puts me at 9.004"
I can breath now.
04-17-2003, 03:08 PM
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Car: 1989 Camaro RS
Engine: Vortec 350
Transmission: Built 700R4
Originally posted by flyin89
The 345NP is also made in a hyper design.
I won't use them because:
1) They are made harder but that also makes them brittle so if you do push it to hard they scatter.
2)The piston sits at least .020 in the hole if you believe this is only
.25 drop in compression you are dreaming.
The 345NP is also made in a hyper design.
I won't use them because:
1) They are made harder but that also makes them brittle so if you do push it to hard they scatter.
2)The piston sits at least .020 in the hole if you believe this is only
.25 drop in compression you are dreaming.
2) I think we could use the manufacturer's compression rating on this one. Personally, I don't trust what people say when they refer to cylinders as "holes."
04-17-2003, 08:10 PM
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Originally posted by fast89RS
1) Hypereutectic pistons are not stronger than forged pistons. They are stronger than cast because of a higher silicon content. That is what makes them more brittle. I run hypereutectic pistons in my 383 and have had none of my pistons "scatter."
2) I think we could use the manufacturer's compression rating on this one. Personally, I don't trust what people say when they refer to cylinders as "holes."
1) Hypereutectic pistons are not stronger than forged pistons. They are stronger than cast because of a higher silicon content. That is what makes them more brittle. I run hypereutectic pistons in my 383 and have had none of my pistons "scatter."
2) I think we could use the manufacturer's compression rating on this one. Personally, I don't trust what people say when they refer to cylinders as "holes."
I build engines for customers and have been building them pratically all my life. Forged pistons are not "stronger" they are softer and more forgiving take a hammer hit a forged piston it won't break it will bend and fold. Hit the hyper and pick up your chips. There are a lot of things that can make a piston scatter detonation,valvetrain,etc... I'd rather know I have a buffer zone
If you were to build motors and were constantly involved with machinists you would call a cylinder hole a "hole". But you obviously don't so... Have a nice day.
Last edited by flyin89; 04-17-2003 at 09:08 PM.
04-17-2003, 08:17 PM
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Originally posted by AJ_92RS
Nevermind..... :sillylol:
I just went and actually measured the compression height (I don't know what the 1.83" is...) and it's 1.564"
That puts me at 9.004"
I can breath now.
Nevermind..... :sillylol:
I just went and actually measured the compression height (I don't know what the 1.83" is...) and it's 1.564"
That puts me at 9.004"
I can breath now.
04-17-2003, 09:29 PM
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Car: yy wife, crazy.
Engine: 350, Vortecs, 650DP
Transmission: TH-350
Axle/Gears: 8.5", 3.42
Originally posted by flyin89
The hyper pistons have held up fine in most 350's I've seen in 400's the stroke + the short rod makes the piston rock more. that is what usually breaks them. You should mock assemble it (your 350) and then just have it milled zero deck if you really want to gain that compression back. Sorry to give you bad news but better to know now than later.
The hyper pistons have held up fine in most 350's I've seen in 400's the stroke + the short rod makes the piston rock more. that is what usually breaks them. You should mock assemble it (your 350) and then just have it milled zero deck if you really want to gain that compression back. Sorry to give you bad news but better to know now than later.
From what I've calculated using online compression calculators, with a .025" deck height, that puts me right at 9.5:1 comp. Why is that bad? That's what I'm shooting for.
I guess what's bad news to you isn't to me...
04-18-2003, 02:13 PM
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Car: 92 camaro
Engine: 383 stroker
Transmission: probuilt 700r4
hey flyin are you still running the 10 bolt rear? if so what have you done to it to make it hold up? i ran 12.4 last yr and was waiting for mine to go ill be in 11's this year thanks
04-18-2003, 04:07 PM
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Car: 1986 Pontiac TA
Engine: 383
Transmission: 700R4
Axle/Gears: 3.70
Flyin - All Natural, no spray!
I like to keep the outside looking pretty much stock minus decals. I've owned it since new and it only has 36,000 miles on it.
www.geocities.com/dzperf
I like to keep the outside looking pretty much stock minus decals. I've owned it since new and it only has 36,000 miles on it.
www.geocities.com/dzperf
04-18-2003, 08:11 PM
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Originally posted by 383LT1intake
hey flyin are you still running the 10 bolt rear? if so what have you done to it to make it hold up? i ran 12.4 last yr and was waiting for mine to go ill be in 11's this year thanks
hey flyin are you still running the 10 bolt rear? if so what have you done to it to make it hold up? i ran 12.4 last yr and was waiting for mine to go ill be in 11's this year thanks
No joke I still have the 7 5/8 (71/2) Rear Powertraxx locker and 28 spline axles no probs yet.(knock on wood)
04-18-2003, 08:13 PM
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Originally posted by HiTech5
Flyin - All Natural, no spray!
I like to keep the outside looking pretty much stock minus decals. I've owned it since new and it only has 36,000 miles on it.
www.geocities.com/dzperf
Flyin - All Natural, no spray!
I like to keep the outside looking pretty much stock minus decals. I've owned it since new and it only has 36,000 miles on it.
www.geocities.com/dzperf
Totally awesome I really like your car!
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