Tune with Boost Question

[jqn2049]

The 5.2 manifold bolt pattern is different from coyote so the manifolds will not bolt on.

Read your other posts saying how they’re configured 90 degrees from the stock one. Is there a way to overcome that? Or would it be best to just use the stock GT headers and separate the cat from this eBay item and do the steps you said above? Sorry for so many questions, just wanna gauge the level of effort before plunging into buying something

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[K4fxd]

It's the GT350 heads that you can move the studs. So never mind.

 

[engineermike]

The kicker is that ford diagrams seem to show that the 7g has the 5.0 pattern on the passengers side and 5.2 pattern on the drivers side.

 

[jqn2049]

The kicker is that ford diagrams seem to show that the 7g has the 5.0 pattern on the passengers side and 5.2 pattern on the drivers side.

Maybe some Frankenstein build might work where you use gt500 header on driver side with cat and stock gt header on passenger side with gt500 cat welded on like you said

 

[K4fxd]

Looks like the easiest thing to do is buy a left side 1st gen manifold.

 

[engineermike]

Looks like the easiest thing to do is buy a left side 1st gen manifold.

I thought that as well but I’m almost certain the 2-bolt flange is clocked 90 out from the 5.2.

 

[K4fxd]

I thought that as well but I’m almost certain the 2-bolt flange is clocked 90 out from the 5.2.

I'd make an adapter. I hate welding to stainless unless I have a proper shop and welders. TIG and back purge. I know it's just a matter of time till it cracks.

 

[jqn2049]

@engineermike just circling back on this, if i got the gt500 catalytic converters (whether from that ebay link or used); if i were not able to do the install steps you outlined, can I just remove the catalytic converters from the gt500 pipes and weld them onto my GT?

 

[engineermike]

I don’t see why not. The upstream side is actually bigger so it should weld up without issue. The downstream side might require a pair of these:

https://www.adlerspeed.com/products...-turbo-exhaust-reducer-connector-adapter-pipe

 

[jqn2049]

@engineermike thanks! Just wanna say thanks for all the help. Reading your threads has really taught me a lot on catalytic converters in general. I’ll probably stick with the stock cats for now and take it easy on the car.
Fwiw for any California owners, called numerous shops in my area and they said they can do it, but highly recommend not to and that smog tests in the area are so strict/detailed that I’d have to continuously remove the gt500 cats and put the stocks back on every year regardless. They also mentioned that the only cats that fail seem to be extreme abuse (back to back pulls without cooldown, WOT for longer than 10 seconds, road racing). As long as owners don’t do dumb stuff with the car, cats should last for a long time.

 

[engineermike]

@jqn2049 there are some tuning tricks I can show you that can help preserve them as well. The entry fee is only about $300 for pcmtec.

 

[jqn2049]

@engineermike id rather stay on the stock whipple tune for now thanks. question I had for you is have you had to do smog testing since you've put in the gt500 cats? Or what's your plan when that day comes? From what shops have told me, that would not pass smog, so would you just put your stock cats back on?

 

[engineermike]

So basically I believe the issue with stock cats is thermal shock. The whipple tune at low rpm runs very low timing and lean A/F ratio, which is a recipe for rapid heat-up and thermal shock. Every failed cat I've looked at had cracked ceramic substrate. Ceramic doesn't crack from high temps, but rather from stress which can only come during uneven heating/thermal stress. All I do is richen the A/F up at low rpm, lower the cat overtemp temp setpoint, and possibly lower the min A/F ratio during cat protect conditions. It's only safer.

On emissions checks, my region does a PCM DTC scan and visual inspection regarding cats. Mine passes both with no issue and no tuning "tricks". On the visual part, there's no way an inspector knows, visually, the difference between a GT500 cat and a GT cat. They've looked right at them and took no issue.

 

[K4fxd]

have you had to do smog testing since you've put in the gt500 cats? Or what's your plan when that day comes? From what shops have told me, that would not pass smog,

How is the shop going to know? If some sharp dude sees the welded on flange all you do is claim stock replacement.

 

[jqn2049]

How is the shop going to know? If some sharp dude sees the welded on flange all you do is claim stock replacement.

How is the shop going to know? If some sharp dude sees the welded on flange all you do is claim stock replacement.

I was more so wondering if it would throw a code or something

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