oilwell1415

I've heard about the Bassani headers, but havn't noticed any comments about the JBA headers. Is anyone running these? If so, how well do the work?

Silver-Bolt

How about the "Doug Thorley" custom headers. I see him advertised in a lot of mags. Anyone tried yet?

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2000 Silver Lightning (13.82 stock)
2000 Mercedes ML430 (16.01 stock)
1996 Donzi ZX-33 (Twin 502's) (81 mph)
In the works: Muzzy ZX12-R 200++ mph (9.94 stock)

RedDevil

I have Bassani Headers and I lost 2 psi of boost. I run no faster then my friends stock header L. The reason I am told by SVT is the cams were timed to the blower and the STOCK exhausts. The blower needs residual prerssure (2 psi) on the incomming intake stroke. The headers work so good that there is NO residual pressure and thus a lack of full Pressure on the intake stroke in the cylinders. Which our blowers put out 8psi of boost- period. So 8 psi going into a cylinder gets 8 psi w/residual boost. 8 psi going into a cylinder with no residual boost is 6 psi. That's how it was explained to me.
That's why I am taking them off and testing the stock headers with PSPs NEW LOWER PULLEY next week.
Even with the NEW Lower Pulleys coming out SOON you still will have to make up the 2 psi of boost-lost with headers.
As you can tell from other guys times-I believe Johnny Lightning and Spiro run stock headers while Jim @JDM has long tube headers and runs slower.
WHY????
Save your money unless changing cams are in your future, IMHO.
If SVT is wrong then I stand corrected!!!

Dan

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12.77 @ 105.80 mph
So-Far!!

[This message has been edited by RedDevil (edited 01-09-2001).]

Sixpipes

I've got JBAs. I've noticed no gains in performance, but I haven't lost any either. The headers on the Lightnings are the biggest POS on the whole truck. I just feel better having them off there. As far as workmanship and asthetics, a big improvement and I dropped about 5 pounds.


Pretty dramatic difference, hey?



[This message has been edited by Sixpipes (edited 01-09-2001).]

oilwell1415

There is more to making power with a blower than building boost. A roots blower isn't efficient becaue it requires engine power to operate. The higher the boost goes, the less efficient it is. If you remove a restriciton in the system and the boost drops that's a good thing, it means the engine is operating more efficiently. The fact that your truck runs the same now as it did before with only 8psi illustrates that perfectly. The name of the game is airflow. If the engine flows well enough to drop boost, that means more air is going through the engine. The blower makes boost because it is trying to force more air into the engine than the engine can use. If your engine could move that much air without the blower it would make even more power because there wouldn't be any lost to the blower. For example, the blower on a top fueler takes about 500 hp to turn going down the track. If the engine could move as much air without it there would be 500 more to get the car down the track with. Same story on a L. If the blower does less work to get teh same airflow, you get more power. Whether or not the truck goes faster is a matter of many variables, so more power may or may not show up on the time slip.

RTKILLA

Any blower require engine horse power to run it.

I don't know about you guys, but I didn't loose any boost with my bassani setup, and I did headers back. Still about 11.5 at wot

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She has allot of toys on her.
MAY BABIES STAT'S
Built 5/4/99
# 917 of 4000
Best ET. 13.42 at 100.98
best stock 13.96 at ?
2001 ET: 12.???
When the green light drops, the bullsh*t stops.

Gitchi Manitou

That's why turbos are considered a much more efficient power booster, they don't require engine power to operate.

Hmmm...Headers by "Doug" I remember him from way back to the days of **** Landy, Jack Chrisman, Roger Lindamood, oh you get the idea.

[This message has been edited by Gitchi Manitou (edited 01-10-2001).]

Hamrhead

oilwell's got a good point.I had a '93 Cobra a couple years back and bought a BBK Instacharger for it.It was the 9psi kit for the GT motor.Besides the fact that the Cobra motor had better heads etc. than the GT,I also put a full exhaust on it.Well,the kit was designed to add about 100 horsepower at 9psi on the GT motor,but on my Cobra it made about 6psi.It was still adding the 100 horses,but it was much more efficient,which is a good thing.The more you compress air,the hotter it gets.So if you can make the same power w/ less boost (because of better airflow),the air will be cooler,and that means more power,less chance of detonation.But being as we have an intercooler,you might as well get the pulley to get the boost back up to where it belongs!! If this is confusing,it's because I've been awake too long!!

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Mike Hague
BLK'99 13.36@102.26
'95 Cobra R 13.18@106+
'91 GMC Syclone 12.0's@111.5,,,so far

MYREDTOY

Got the bassani headers. Didn't see a lot of improvement but like the look. Did not loose any boost. Was getting well over 10 psi of boost before and now with other mods am getting over 12. I do have a piller mount gauge so boost is not estimated. Steve

Silver-Bolt

Oilwell. Isn't the Eaton designed to only "move" a specific volume of air? Not a specific amount of pressure. My understanding is that the eaton will only produce 112 cubic inches of air. This is where volume and pressure are not necessarily directly related. It is possible to delivery that same 112ci at a higher pressure. Hence the pulley changes. You will be forcing the same displacement at a faster (more pressure) rate making more horsepower.

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2000 Silver Lightning (13.82 stock)
2000 Mercedes ML430 (16.01 stock)
1996 Donzi ZX-33 (Twin 502's) (81 mph)
In the works: Muzzy ZX12-R 200++ mph (9.94 stock)

Jeff S

The larger crank pulley/smaller blower pulley makes more "pressure" because it spins the supercharger faster relative to engine RPM.

I chuckled at the "SVT timed the cams" comment since there is nothing special about the Gen 2 Lightning cams.

These cams have VERY little overlap and incredibly puny duration, so I really don't understand how a more efficient exhaust could cause a drop in boost pressure.

That said, I also don't think there's a lot of power to be found in changing exhausts (based on the results of non-biased sources). Obviously the factory system, no matter how ugly, is pretty efficient. However, I want to change the pipes on mine solely for a nicer sound.

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Later!
Jeff S.
President, NLOC
#74 in '95 - 11.92@115.2
#582 in '00 - 13.36@101.75 (Swanson chip ONLY)

oilwell1415

It is true that the blower moves approximately the same amount of air regardless of pressure, lets imagine that a stock engine in stock form can flow 90 ci of air with no boost. Then we bolt on a blower that is trying to move 112 ci of air. The extra air the blower is trying to move backs up inthe plenum and becomes pressurized until a state of equilibrium is encountered. If 6 lbs of boost is enough to make the engine also flow 112 ci, then you will get 6 lbs of boost. However, if the engine is modified to flow more air, say 105 ci, the blower is still only trying to move 112 ci. Less boost is required to make up the difference. So, volume of air moved AFTER the blower is related to pressure. This is why blow through supercharger have pressure relief valves. When you are at 6000 rpm and lift, the blower is moving enough air to produce 10 psi (reference only), then when you lift the blower is still moving at the same speed, but boost skyrockets because there is a larger restriciton after the blower.

oilwell1415

I got a good chuckle out of the whole SVT reply. Blowers have been around long enough they shouldn't have had to put a whole lot of thought into bolting one up.

I don't think there will be much gain over stock because a) the air can't get past the valve/port fast enough for the exhasut to cause a restriction, and b) because they aren't long tube headers. I think a set of properly designed longtubes would make some power. That said, I'm going to put on headers when I get my truck because I plan on doing ported heads and bigger cams in the first year or two of ownership. I don't to mess with a crusty nasty exhaust later.