91Z and Mr.HO. Do you know the Shinola Man? As in S*** from Shinola. George, you're some sort of mechanical engineer or designer right? You should know this stuff. Kevin, your a computer nerd right? I can't blame you for ignorance.

During the blowdown process, it is essential to use the kinetic energy of the out-going exhaust wave, followed then by an expansion wave in which the pressure is reduced in the exhaust port region.
What is a wave is actually a series of pulsations, and the goal of the header designer is to make these waves assist in scavenging the other cylinders. ie: 1 5/8 & 1 1/2" or step headers.
It may help to think of scavenging like siponing, having the inertial column create a low-pressure region that aids the companion cylinders during blowdown. When a system is designed as such, it is considered to be tuned.
Given two engines of the same displacement and power, but operating at different RPM levels, the one with the higher engine speed will require the larger-diameter primary tube. This is a function of shorter evacuation time combined with higher piston speeds. When the camshaft profile is altered appreciably, the tuning effect of the exhaust system becomes more important. Mild cam grinds of 225 degrees or less on the intake lobe produce lower cylinder pressures at the end of the exhaust stroke. Camshafts with larger amounts of duration are much more sensitive to larger primary tubes.
Lets see. My piece of S*** TES 383 made 409 RWHP at 5400 RPM. I HAVE A SUPER RAM, STILL A TPI, STILL MAKES POWER BELOW 6000RPM. My camshaft intake is 224. What will larger headers do? Make MAYBE 6 HP more at peak RPM? Maybe 3 ftlb more? You guys are splitting hairs.
Yes Sumiit states the SLP's made more power than the TES. What was the engine? NOT A TPI!!! A 383, Comp Cam 292 Magnum camshaft, double pumper Holley, ported heads with peak power at 6500 RPM. Sorry, that is not close to a TPI comparison. WE HAVE SINGLE EXHAUST! Before you sling S*** do your homework.

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'89 IROC
Long Rod 383
Super Ram, Nitrous
T56 6-Speed
'99 Z/28 6-Speed

[http://www.dan89iroc.cz28.com]

 

A while back, about a year ago, I was looking at my TES headers and thinking about the different diameter primary pipes and the reason behind it. What I noticed, was that the longer downtubes had the larger primary, and the shorter downtubes had the smaller primary.

It made sense to me, that by doing it this way, Edelbrock designed in effect an "equal length" shorty header. Since it is impossible to design a true equal length shorty header for a 3rd gen, this is another method to arrive at the same result.

The exhaust gases in the larger tube, have a longer distance to travel, so the larger tube offers less resistance to flow. The smaller tube, being shorter in length, has more ressitance to the flow of gas. At the collector, where they all join together, the exhasut gases have all traveled basically an "equal length" and reach the collector at the same time.

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FORMULA 350 TK
Southern California 3rd Generation F-Body Organization©

 

Been there done that! If that logic makes you happy so be it!
You'll just have to wonder how fast you could've gone.
Don>>>

------------------
Chronologically challenged. But still kicking!
92 CAMARO RS
305 TBI 5/spd (now TPI)

'69 camaro-BB/Lenco,1050 dominators, /Pump Gas/no drugs 8.97-150+

 

Hey Dan, how come you didnt tell us you got your engine dynoed??

I still think what George said in the other thread applies. Why use a 1.5" header when your exhaust valve is 1.50", or 1.60" ? Doesnt make sense. Plus they have crappy welds at the ports, making the header appear even smaller. And that D-shaped collector?? I think Edelbrock's thirdgen headers were designed before GM gave them 350 engines, and they never bothered to update. My friend's 87 IROC runs 2 1/8" headers on his 850 HP carb'd engine, and he runs mid 8 second times in NHRA drag racing. He tried smaller headers and that large size gave him the most HP.
I guess we'll have to agree to disagree here, on this issue. You can promote your TES headers for cost, ease of installation, and detailed instructions, and I'll say they stink on built 305 and 350 engines, and SLP's are better contruction, made of stainless steel, and worth the extra cost.

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West Coast GM Shootout 2001!
1991 Camaro Z28
5.7L 5-Speed (originally 305)
13.25 @ 107.18 MPH
Southern California
Member: SoCal 3rd Gen F-Bodies
Webmaster: SoCal F-Bodies
-=ICON Motorsports=-

 

Edelbrock designed the same header setup for the G-body cars. When dyno tuning a 350 El Camino a shop noticed the way they put the system together and knew there had to be a better way. After only getting 160 RWHP he sent the car to me to fix it. I modified the crappy system and sent it back for futher tests. It then produced 210 RWHP. To me this is knowing S**t from Shinola.

Don>>>

------------------
Chronologically challenged. But still kicking!
92 CAMARO RS
305 TBI 5/spd (now TPI)

'69 camaro-BB/Lenco,1050 dominators, /Pump Gas/no drugs 8.97-150+

 

My experience:
the 305 loved the TES & Y gaining approx 25hp. Have yet to test the SLP on the 305 but would probably gain a small but significant amount.

SLP was a huge improvement of at least 25hp over the TES on my 383. No comparison whatsoever. The TES was so restrictive on the 383 that I simply could not lean the A/F down enough to even find max power.
The SLP's were tremendously more effective and much better quality pieces, although they were anything but simple bolt-ons. I had to grind on them for about 7 hours (have to use carbide on stainless) to get everything right to my tastes & fitting in the car. Still I like them, and my only future mod to them will be TIG welding a 3" collector & Y to them to replace the 2.5" collectors (same as the TES by the way).

Anyway no dyno numbers, just realworld results. I use trap-speed & vehicle weight and work my way backwards for HP numbers. I have no trust in dynos as they relate to actual racing. No offense Don, I realize they are a comparison tuning tool. I just prefer the Vericom2000 acellerometer for the last 9 years.
oh Don, what's wrong with drugs anyway?



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White 1986 Irocz, 305/383 with Edlebrock Performer-RPM intake and Performer #1407 carburetor, +110hp shot of crack, 700R-4 tranny, 3.25:1 rear, Mcreary Road-Stars, single 3" Borla exhaust, Linginfelter-TPI camshaft pulls 17" vacuum solid. N/A runs 10.9 @124, Crack-runs 10.3 @135... haven't run at track since Oct-99

 

Is this Dyno Don Nicholson, the 1966 AHRA champion? Wow, I'm sorry to have debated exhaust flow technology with you. You were an icon back then. Oh well, guess Shinola land is right here in my front yard. You're right, Edelbrock must have a lousy R&D department. I'm going to pull those S*** TES headers off tomorrow and buy the SLP's. By the way, do you have a grinder I can use so I can install the SLP's in less than 8 hours?

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'89 IROC
Long Rod 383
Super Ram, Nitrous
T56 6-Speed
'99 Z/28 6-Speed

[http://www.dan89iroc.cz28.com]

 

No And No!

------------------
Chronologically challenged. But still kicking!
92 CAMARO RS
305 TBI 5/spd (now TPI)

'69 camaro-BB/Lenco,1050 dominators, /Pump Gas/no drugs 8.97-150+

 

Yeah Dan, I'm a Mechanical Designer by experience (not a professional student). I've known that theory for awhile know, nothing new to me (who did who's homework). Yes, that is all correct, but let me ask you this. Since you designed your engine for lower RPM use, you are right that the 1-3/4" probably will only give you 6HP at peak. But why are you concerned about peak, are you gonna drive everywhere at 5400 rpms? Peak really doesn't matter, it's the power increase throughout a broad range of RPMs. Those Edelbrocks sound good, "Dual diameter primaries, smaller primaries are longer, lager primaries are shorter ..." Sure, sure, sure, they must work. The smaller/longer pipes allow RESTRICTION (doesn't this mean to slow down/resist?) for low-end torque, while the larger/shorter pipes have less restriction (then these pulses are travelling faster, correct?) for more upper rpms power. Based on the theory you posted, the Edelbrocks are not TUNED! Well, maybe they are, but for a narrow rpm range.

Let's take a look at your "383". So you are just putting numbers up with Edelbrock headers and you think that is the best combo for you're engine? Blindly based on ONE set of headers? So if you would have used 1-1/2" headers, you'd be happy with them? They produce better low-rpm torque after all. I know your system will make more PEAK numbers with 1-3/4" headers, but will it make a more broader power range, dunno. I do know your engine is begging for at least 1-5/8 primaries throughout. And no, the edlebrocks are not 1-5/8, just half of them are.

Also, what does a single exhaust have to do with the headers? As you said, it is all about TUNING. Remember the Y-pipe discussion we had at Cruiser's during the West Coast Gathering? That applies to everything in the exhaust (and intake) to produce gains. Why leave what GM designed based on a budget and for a 200 rated hp engine?

Oh one final thing I remembered, the primaries should be of similar size (not smaller) than the exhaust valve (E.V. = 1.60"/ Primary = 1.625") being used. Otherwise, why have the 1.60" valve with a 1.50 primary?

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George P. Lara
1984 "L69" A4
1994 LT1 M6
Member:
SCCA, SCFB, SC3GFB

 

Dan, thats Dyno Don Lorentzen, my father, and ex-NHRA Pro Stock racer from the 70's.

He's installed several sets of Edelbrock and SLP headers on SC3GFB member's cars, and we both prefer the SLP headers light years ahead of the Edelbrocks. I dont know why ODB had to spend 8 hours grinding SLP headers to his liking, but the Edelbrock headers need similar grinding to open up the exhaust ports. Edelbrock's welds arent that great. We are talking about mass-produced stuff here... How come you bought the SuperRam then, if you're worried about how long it takes to install something?

 

oops sorry I forgot to mention the fact that my SLP's are the 1.75" primary model.
and about the 7 hour deal, yeah I am slow and very picky. I took down the lower part of the mating flange in several areas to help fit sockets over my sparkplugs (big problem), then I grind near where the bolt heads will be to improve access with an open-end wrench or socket to the header bolts. Then I had to trim a little to clear my steering rod, then I had to port match the flange openings to my gaskets & remove all the flange weld to make it smooth without the air-injection tubes projecting, etc...
you get the idea,
and finally wrapped them in thermotech (wasn't counting that time).



just warning you all if ya care..


------------------
White 1986 Irocz, 305/383 with Edlebrock Performer-RPM intake and Performer #1407 carburetor, +110hp shot of crack, 700R-4 tranny, 3.25:1 rear, Mcreary Road-Stars, single 3" Borla exhaust, Linginfelter-TPI camshaft pulls 17" vacuum solid. N/A runs 10.9 @124, Crack-runs 10.3 @135... haven't run at track since Oct-99

 

yeah hahaa don't ever let me charge you for labor time.
I take lots of breaks!



------------------
White 1986 Irocz, 305/383 with Edlebrock Performer-RPM intake and Performer #1407 carburetor, +110hp shot of crack, 700R-4 tranny, 3.25:1 rear, Mcreary Road-Stars, single 3" Borla exhaust, Linginfelter-TPI camshaft pulls 17" vacuum solid. N/A runs 10.9 @124, Crack-runs 10.3 @135... haven't run at track since Oct-99

 

ODB: Well, if you wrapped your headers, you had better remove it soon before it ruins the metal, every header manufacturer will tell you, wrap our headers and your warranty is void.
Oh, building an engine to make power takes lots of things one being pride, I see no pride in pushing a button to make power and go fast. Skip the drugs do for real!

Don>>>

------------------
Chronologically challenged. But still kicking!
92 CAMARO RS
305 TBI 5/spd (now TPI)

'69 camaro-BB/Lenco,1050 dominators, /Pump Gas/no drugs 8.97-150+

[This message has been edited by Dyno Don (edited February 03, 2001).]

 

I talked to slp and they said that wrapping stainless headers will crack them. I don't know the validity of this but I'm not about to try.

 

Yeah Dyno you are soooooo right ODB only goes to 10.9 without nitrous. You should hang your head in shame ODB. The NHRA only uses Nitromethane which is a power adder, no wait IHRA has a turbo and supercharger class, no wait tractor pulling has supercharger class, no wait oh never mind you get the pic. Why is doing things the hard way always right for the hard headed. I don't like the juice but thats only because I have to fill the bottle unlike a supercharger. If you really are into speed than you would respect it in any form. The real challange is to make as much power as possible without going broke. That means big cubes and the juice. Silly man!

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84 Camaro ZZ4 with HOT cam. 1.88 60' (12.98 @ 105MPH E.T.)
Other Mods: You name it and I have probably changed it.

2001 Dodge Ram Quad Cab 5.9L 4*2

ASE Certified Auto Tech
LIVE AND DIE BY THE ALMIGHTY BOWTIE!

[This message has been edited by CamaroMike (edited February 04, 2001).]

 

Mr. HO, get your car running and we'll talk.

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'89 IROC
Long Rod 383
Super Ram, Nitrous
T56 6-Speed
'99 Z/28 6-Speed

[http://www.dan89iroc.cz28.com]

 

Dooh! Keep it above the belt now. Yeah, I'll finish it sometime, I'm trying to beat you're record.

 

Dyno Don,
Well realistically I doubt SLP would honor a warranty anyway, but I'm not really worried about that. So far I've had no problems with the SLPs so maybe they will be fine for several more years.

Ah about the pride thing. I'm not too worried about that either, but I'd rather not have so much pride that I lose races to those people who have none.
Hmmm and the button... tell you what, you don't push your acellerator pedal and I won't push my button.


*once a crack addict, always a crack addict


------------------
*I do custom performance mods on Edlebrock Performer carburetors (dualplane intake mods in the works),
White 1986 Irocz, 305/383 with Edlebrock Performer-RPM intake and Performer #1407 carburetor, +110hp shot of crack, 700R-4 tranny, 3.25:1 rear, Mcreary Road-Stars, SLP-stainless 1.75" shortie headers & Y-pipe, single 3" Borla exhaust, Linginfelter-TPI camshaft part number 74216 pulls 17" vacuum solid. Cam specs 213/219 @.050 114-LSA, .462/.470 lift @1.5:1 ratio. MSD-6AL, billet distributor, multi-retard, blaster-3 coil, and RPM switch.
N/A runs 10.9 @124,
Crack-runs 10.3 @135
haven't run at track since Oct-99