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Discussion Starter · #1 ·
Monday I will be purchasing a set of the Gen 2 Tri-Ys for my Impala. I have the ARP bolts and I have gaskets, they are Fel-Pro but I cannot remember which part number. I decided that since I have to replace the exhaust manifold gasket I might as well just do the headers. Especially since I have no real time frame on an LS swap and I'd like to use this car as a daily driver again.
So that leads me to some questions...

EGR: Does anybody have a link to the block off plates I need for the intake? I believe Dan can weld up the exhaust side so that I don't need a block off for that. This car does not fall under emissions regulations so I do not need this.
AIR: I believe that I just remove all the hardware since this is just for the exhaust correct? That is what I have been reading at least.
Plug Wires: I am a fan of Taylor cables. I am looking at these two P/Ns, 84027 and 76047, does anyone have any thoughts on these with the tri-ys or does anybody have a best fit/favorite cable? Preferably do not want to spend $200 on plug wires though.


Also going to do the plugs while I am in there since who knows when they were last done. Stock car just needs the ACDelco coppers correct? P/N: R44LTS?
 

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1. EGR delete / block off plates
Any EGR block off kit will do; duckduckgo will find one for you.
Or you can fab your own or have someone fab them for you.
If headers lack an EGR provision, you may not need one of the plates.
If you disable the EGR Valve creatively, you may not need two of the plates.

2. If Dan's headers lack AIR provisions, then yes, just get the AIRpump stuff outta there.
Sell the AIRpump hardware to another LT1 owner who needs to appease the smog gestapo.

3. MagneCor ignition wires have a solid reputation.
 

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I think I've got jegs brand EGR delete plates on one of my LT1s.

I like my Magnecores but they also run from my LS coils on the valve covers to the plugs so I needed custom wires anyway. MSDs worked fine for a long time.

-Brian
 

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Why delete EGR when you don't have to? No performance advantage ,cylinder temps go sky high less throttle response ,and likely mileage penalty. Why folks are so eager to delete this when they have no idea what it's benefits are is a mystery to me. May as well get rid of the EVAP system too ,huh....
 

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Discussion Starter · #5 ·
@Marky Dissod Thank you. I believe this is the plate I need EGR Delete Block Off TBI Plate Kit for Chevy Camaro Impala GMC C1500 C
Yeah don't have the inspection like that down here.
I will have to go back through Magnecore, did not find the part number for an LT1 (although it was late last night)

@1slow96 I never said EGR was a performance disadvantage. I just don't need it and the mileage penalty with no EGR is miniscule. I've deleted EGR in my gas truck and had no change in throttle response, mileage penalty I could not say because I put in a bigger engine so I am unsure. I don't really know how you would have a change in throttle response considering the EGR valve only opens when you are cruising and idling from what I remember. Plus one less thing to go wrong and throw codes.
In fact GM deleted EGR from all V-8 gasser trucks (don't know about cars) in 2003, guess they don't know what they are doing huh? o_O
I know how it works and I don't need it. Done it before with success. So....
 

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In fact GM deleted EGR from all V-8 gasser trucks (don't know about cars) in 2003, guess they don't know what they are doing huh?
Variable Valve Timing makes the external EGR Valve redundant - but GM did not disable the EGR function.
GM knows full well what the EPA is making them do.
 

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Discussion Starter · #7 ·
VVT was not available until 2010 in trucks, again do not know about cars.
There is no EGR valve on trucks from 03 and onwards. If I remember correctly it was once they got drive by wire they removed the EGR valve. Don't know why it correlated with that but 🤷‍♂️
 

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VVT was not available until 2010 in trucks, again do not know about cars.
There is no EGR valve on trucks from 03 and onwards.
if I remember correctly it was once they got drive by wire they removed the EGR valve.
Don't know why it correlated with that but 🤷‍♂️
That got by me - but yeah, I get how a non-physical throttle can be used to achieve similar results.
 
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I will have to go back through Magnecore, did not find the part number for an LT1 (although it was late last night)
Here is the box and label from my Magnecor set. From 10 years ago but I’d imagine the part numbers are the same:

Wood Automotive tire Bumper Motor vehicle Gas


Rectangle Font Gas Motor vehicle Nameplate


Edit: Their set even works for the ‘97 Impalas and Caprices :)
 

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I didn't notice it mentioned, but a '96 sets the MIL after the AIR is removed unless programmed out. I know you don't care about the code, but the light's a bi$h to unplug. ;)
 
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Discussion Starter · #14 ·
I will be getting it tuned. I had mentioned it in my build thread but not here.

I think my MSD distributor is the reason my Grand Prix won’t start. It’s new straight out of the box. So I have a bad taste in my mouth with MSD right now lol
 

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They seem to show stock
Maybe contact them directly ?
There are cheaper alternatives,
I used magnecor on my LT1 and was pleased with fit and finish.

EGR
Without starting the age old argument, couple things to ponder.
You cruise the LT1 around at a speed and throttle opening that the EGR is wide open and functioning,
the base of intake where all the exhaust is flowing through the passages gets burning hot .
( look at the bottom of an intake sometime at the burned on oil residue)
Now go full throttle to pass, street race, what ever.
I submit the hot manifold will have an effect on performance it that time until the manifold temp comes down.
How much? How long? Can't answer that.

We can all agree the EGRs main intended purpose is to reduce NOx .

Advancement in convertors , different valve timing events , calibrations , chamber designs allow many engines to work without added EGR.

NOW here's my question , if EGR actually on its own increases fuel economy, why don't ALL engines have EGR ?
Yes the throttling deal but if there was a measurable gain in economy one would think the manufacturers would have EGR on everything.
 

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I will be getting it tuned. I had mentioned it in my build thread but not here.

I think my MSD distributor is the reason my Grand Prix won’t start. It’s new straight out of the box. So I have a bad taste in my mouth with MSD right now lol
I had the same experience with a MSD cap and rotor that was defective right out of the box
 

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Take a look at the symptoms of when EGR in non functional (stuck shut) .
Basically the same as being blocked off. Cylinder temps rise precipitously ,
as does the tendency towards detonation ,and reductions in timing to combat this.
Since they only operate at part throttle ,they spend their time opening ,or shutting.
I doubt if they're ever fully open. Funny that folks complain about small amounts of
exhaust from EGR into intake ,but never about the larger amounts crated by
camshafts with more overlap 100% of the time engine is running.
Implying this engine runs better w/o EGR and/or gets better mileage is
not supported by any data that I've seen. Comparing to other motors seems
more than just a little intellectually dishonest. It's apples ,and oranges.
 

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Look at the adders in the tables.
You take out the the added timing the stock calibration throws at the LT1 when the EGR is open and those symptoms don't occur.
Advocates say you can run more timing with EGR , I say you have to .
My personal experience with my LT1 was not what you saw.
No EGR and tables set to account for no EGR I found it more throttle responsive.
While the NOx numbers were elevated, they were well under the IM240 bar.
I would reactivate the EGR for testing just to be sure, along with the EGR adder tables.
No proof , seat of the pants take it as you want , the car was more soggy light throttle changes to me.

I don't have an LT1 any more so I can't do any more testing and dyno part load checks. Just the dyno
Someone will need to do some steady state runs .
Find the optimum timing each will handle and report back the fuel numbers.

As for "self egr" as people like to call it,
Sure we do complain .
You trade high RPM power for poor low speed , less power at low RPM than stock cams all other things equal.
While part of the big cam downside is unburnt air fuel going right out the exhaust port, a big part is the exhaust polluting the intake charge at low speed.
People seen to misunderstand that , that cool idle is the engine running like crap.
Agree to disagree with our opinions, and I do.
 
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