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Old 12-11-2009, 08:09 PM
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exhaust crossover

I was wondering about a set of brodix -8 pro cylinder heads. If I wanted to use them on an egr equipped vehicle could I someone put an exhaust crossover in the heads. The heads have no exhaust crossover and I am wondering if they could ever have one without major money?

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Old 12-11-2009, 11:14 PM
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I wouldn`t even consider attempting to put one in. You`ll have to plumb it from a outside exhaust source. This same way is done on Vortec heads from the factory as they too have no exhaust heat riser. There maybe info out there on how to do so with headers and some small exhaust tubing as I`ve heard other rodders doing the same thing with vortec heads.
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Old 12-12-2009, 05:40 PM
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Quote:
Originally Posted by crussell85
I was wondering about a set of brodix -8 pro cylinder heads. If I wanted to use them on an egr equipped vehicle could I someone put an exhaust crossover in the heads. The heads have no exhaust crossover and I am wondering if they could ever have one without major money?
I guess my first question would be why are you running what is esentailly a race head on a vehicle that needs to pass emissions?

Second is to agree with Double Vision, if you just gotta, the plumbing can be run externally. GMPP and Edlebrock used to have pieces for Vortecs onto earlier emission vehicles with TBI. But this stuff is getting hard to find, the last GEN 1, Vortecs getting to be a decade old at this point.

For a do-it-yourselfer it's just tap into the exhaust and run a tube to a suitable intake or an adapter to mount the EGR and connect its output to the intake.

Bogie
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Old 12-12-2009, 07:57 PM
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I run an airgap on my 489 BBC WITH A HOLLEY 850 dp and it's carb ice country so I drilled out a 1" 4 hole spacer for a coolant port under the front of the primarys. I have a valve to be able to control how much heat if any and it works great. $20 aluminum spacer and a long 3/16" drill bit, pipe tap and some fittings and 1/4" tubeing. It works well and you can turn it off when you don't need it!
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Old 12-13-2009, 01:57 AM
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there is no emissions laws here to worry about. I am wanting the egr to work to pick up some gas mileage. I would like to hear some more information on this external plumbing that bogie is talking about, it would be great to see some pictures of it also if anyone can throw some links at me.
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Old 12-13-2009, 03:32 AM
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The EGR system is not used to increase gas mileage, it is used to reduce combustion chamber temps which in turn reduces Nox emissions caused by running lean part throttle mixtures. The lean part-throttle mixture is to help mileage, not the EGR.
Since you have no emissions testing/inspecting to worry about, I would save myself the headache.
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Old 12-13-2009, 04:01 PM
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a bad or improperly working egr valve will hurt gas mileage. EGR is exhaust gas recirculation. It means it is taking exhaust gas and reburning it with new fuel from the tank. If the egr is not working there are no exhaust gases being burnt. I would still like to know on how to set up the egr externally, if anyone would share this with me. Thank you
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Old 12-14-2009, 11:27 AM
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I think you misunderstand how the EGR system works. Check this link: http://www.asashop.org/autoinc/nov97/gas.htm
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Old 12-14-2009, 12:35 PM
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Quote:
Originally Posted by crussell85
a bad or improperly working egr valve will hurt gas mileage. EGR is exhaust gas recirculation. It means it is taking exhaust gas and reburning it with new fuel from the tank. If the egr is not working there are no exhaust gases being burnt. I would still like to know on how to set up the egr externally, if anyone would share this with me. Thank you
EGR is used to lower combustion temps which in turn reduces NOx emissions. This could increase fuel consumption because a driver compensates for the lost power with more throttle. The way to improve fuel mileage is to run the compression up as high as the fuel octane and the vehicle configuration can stand.

But factory part selection offers less than ideal solutions. Which is to say that just running the compression up without paying attention to chamber shape which includes the piston crown results in a less than an optimal solution. Toss into this the head material. Aluminum moves heat faster than cast iron and at the same compression ratio will show less power and more fuel consumption. To compensate, aluminum heads are run at about one ratio to a ratio and half higher than cast iron to get the same power and fuel burn. They tolerate the higher compression simply because they pull heat out of the chamber faster than iron. What aluminum offers is weight reduction and greater repairabilty should a valve get loose. They aren't there for their extraordinary power generation.

If you just gotta have EGR you need the system that hooks it up and the control circuits that operate it. For computer controlled engines that's done with the computer and its sensors, for a non computer engine you need a series of vacuum and temperature switches that supply a control vacuum to the EGR valve based on engine conditions as it's on or off depending on operating temps and power demand.

To start with you'd need an intake that mounts an EGR valve and fits your heads. Since your heads have no exhaust cross over passage, you need to provide exhaust to the EGR point of source which is usually from the cross over. That means the cross over in the manifold would be drilled and tapped to accept a fitting say 3/8s to 1/2 NTP to 3/8's tube flare or compression. On the exhaust manifold you'd drill and tap for a like fitting, for a header pick a tube to weld a piece of 3/16s to 1/4 inch plate with a like hole drilled and tapped for the same type fitting. Between the two fittings run a length of tube. There is a kit for Vortec conversions using the GMPP or Edlebrock TBI with EGR intake that uses an Edlebrock adapter 2899, and a GMPP fitting 12552329 with tube 10220275 but this fits only Vortec intakes. GMPP also makes an exhaust manifold with the location for the fitting.

But if you don't need to meet emissions, EGR is something you just don't have to mess with and doesn't offer you anything but reduced NOx emissions. Exhaust gasses are already burn't all they do is occupy space and reduce power which you compensate for with more throttle position. Without EGR you have to supply more fuel to keep the mixture from going lean, but you're getting more power so your foot will compensate with less throttle, the net result is probably six of one and half dozen of the other in terms of mileage. EGR is not like PCV there is not enough unburnt hydrocarbon in the exhaust stream to support combustion, where-as much of the gases in the crankcase are escaped mixture that got past the rings and this stuff will burn and is metered back into the intake by the PCV valve.

Bogie
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Old 12-14-2009, 08:10 PM
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ok, I have the edelbrock multipoint conversion kit for t.b.i.

Vehicle:
1993 Chevrolet K1500
383 stroker
Brodix -8 pro cylinder heads
Edelbrock multipoint conversion kit from tbi
GMPerformance 7395 camshaft
flat top claimer series pistons with .5 valve relief

everything for the egr is setup to work, i am just not feeding it exhaust gasses, I am grateful for everyone's advice. I think i still want to set up the egr valve to work properly because everything is there to do it, I just need to feed it. After reading this information is there any fuel mileage gain anywhere. I want to get into the tuning of the computer once I get the equipment to do it because I think there is a lot of mileage there.
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Old 12-14-2009, 08:33 PM
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Try singh grooves
Shane
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Old 12-15-2009, 04:41 PM
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i don't understand the last post
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Old 12-15-2009, 05:27 PM
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Quote:
Originally Posted by crussell85
i don't understand the last post
Singh grooves are gaps cut into the squish/quench deck which are supposed to speed combustion. They of course provide a flame path into the quench deck which does that at the cost of reduced detonation resistance, i.e. an open chamber.

The problem with engines is we live with features that are optimized at some operational and speed (RPM) point. At other points these features are either inadequate or excessive.

Squish/quench is one of these that gives gifts, or not, that functions in weird ways, a large surface provides plenty of squish at low speeds to push the mixture toward the spark plug, a good thing; but provides too much quench, for which you pay for at the pump. At high speeds the squish function is unnecessary but quench needs to be optimized to hold off detonation.

For an engine operated at low to moderate speeds the Singh grooves reduce the blast out effort of squish and reduce the effect of quench by giving the flame front a path into the tightly approaching decks of the piston and head which may speed the burn and provide better power and mileage. At low speed with light load operations this is probably useful. At high speeds the chamber is no longer dependent upon squish to stir the mixture so the function of Singh groove at this point is moot, but they still let the flame front
pass into the quench area, but time for events may be overrunning the difference in less quench. Still this may reduce detonation tolerance.

All types of claims have been made for them, but I figure that when they show up on NASCAR engines as a regular feature, then you can be assured they provide an edge at something useful to them whether that's more top end power, or lesser fuel burn, or greater detonation resistance. Till then, I can't get too excited about 'em.

Bogie
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Old 12-15-2009, 07:05 PM
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Quote:
Originally Posted by oldbogie
Singh grooves are gaps cut into the squish/quench deck which are supposed to speed combustion. They of course provide a flame path into the quench deck which does that at the cost of reduced detonation resistance, i.e. an open chamber.

The problem with engines is we live with features that are optimized at some operational and speed (RPM) point. At other points these features are either inadequate or excessive.

Squish/quench is one of these that gives gifts, or not, that functions in weird ways, a large surface provides plenty of squish at low speeds to push the mixture toward the spark plug, a good thing; but provides too much quench, for which you pay for at the pump. At high speeds the squish function is unnecessary but quench needs to be optimized to hold off detonation.

For an engine operated at low to moderate speeds the Singh grooves reduce the blast out effort of squish and reduce the effect of quench by giving the flame front a path into the tightly approaching decks of the piston and head which may speed the burn and provide better power and mileage. At low speed with light load operations this is probably useful. At high speeds the chamber is no longer dependent upon squish to stir the mixture so the function of Singh groove at this point is moot, but they still let the flame front
pass into the quench area, but time for events may be overrunning the difference in less quench. Still this may reduce detonation tolerance.

All types of claims have been made for them, but I figure that when they show up on NASCAR engines as a regular feature, then you can be assured they provide an edge at something useful to them whether that's more top end power, or lesser fuel burn, or greater detonation resistance. Till then, I can't get too excited about 'em.

Bogie
I was getting a little over 13.8mpg around town with my 406 during the first 500 miles.
700r4(lock up converter) that was slipping 20% on the way home from doing the engine swap.
Vortec headed roller cam 406, in an 85 4 wheel drive Silverado
9.7 compression
Singh grooved heads.
In my opinion they work, 98cid more than the previous engine and roughly the same milage.
Shane
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Old 12-18-2009, 08:12 PM
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changing the subject, i pulled my headers off to weld 3/8 couplings to the two center pipes on each side and I started it up after the headers where off to back it out of the garage and I noticed blue flames coming out of each exhaust port, is this normal? I have never seen or ran an engine with the headers off so I don't know but would like to know
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