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92 or 102mm Throttle Body on 521ci stroked 496 Merc with Raylar Cool Cap intake

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92 or 102mm Throttle Body on 521ci stroked 496 Merc with Raylar Cool Cap intake

Old 03-02-2014, 04:19 AM
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Originally Posted by GPM
How are you getting intake manifold psi, on an N/A motor ?
From the ECU with Rinda Diacom software.

http://www.rinda.com/marine/diacommarine.htm

Last edited by Rage; 03-02-2014 at 04:21 AM.
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Old 03-02-2014, 05:07 AM
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Cant remember off hand but I think the 206 is .64 ish - I am still interested in the "new" cam too.

Have you called Raylar and talked to Larry? Coincidentally, he was always the brains behind all this stuff and can probably rattle off data on all these combinations by memory. I just remembered something else too, you will need to pull the intake and port/machine the snout. I think the opening is only 85MM. They offer a newer bigger intake now too once you get up to the bigger TB's.
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Old 03-02-2014, 09:28 AM
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[QUOTE=Rage;4083057]From the ECU with Rinda Diacom software.

PSI usually refers to Boost, could you be talking vacuum by chance ?
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Old 03-02-2014, 10:42 AM
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GPM, It's measuring absolute pressure. If the pink line is observed baro, then It's pulling about 1" vacuum at the end of the pull indicating there is a small restriction. The only issue with jumping to a 102mm tbody, is you may end up with a lean hole during tip in throttle transition. If you have the ability to adjust your accell enrichment tables you can tune around it. Also, as someone else mentioned, if the intake opening is smaller then the Tbody you'll have to open it up too.
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Old 03-02-2014, 01:17 PM
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Thanks Hax, it had me a little confused reading psi.
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Old 03-02-2014, 03:10 PM
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Originally Posted by Keith Atlanta
Cant remember off hand but I think the 206 is .64 ish - I am still interested in the "new" cam too.

Have you called Raylar and talked to Larry? Coincidentally, he was always the brains behind all this stuff and can probably rattle off data on all these combinations by memory. I just remembered something else too, you will need to pull the intake and port/machine the snout. I think the opening is only 85MM. They offer a newer bigger intake now too once you get up to the bigger TB's.
Thanks.

I exchanged a couple emails with Larry. He mentioned that stroked 496's can use a bigger TB. Raylar's current offering is 92mm max then they put twins on the top of the manifold which will not work for me do to clearance issues with the hatch. So far it looks like the 92mm gains would not be worth it over my current 892cfm ported TB.

Does anyone know if there are CFM numbers available for the 92mm and 102mm LS engine throttle bodies? I have generic TB CFM numbers from the Performance Trends Engine Analyzer software but not sure how accurate those are.

I believe that the stock TB mount does not have enough metal to install a 102mm TB and would have to be cut off and replaced. Given this complexity is why I am looking for reliable info on what HP increase it would net for my engine to decide if it is worth it.

Last edited by Rage; 03-02-2014 at 03:32 PM.
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Old 03-02-2014, 03:16 PM
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Originally Posted by HaxbySpeed
GPM, It's measuring absolute pressure. If the pink line is observed baro, then It's pulling about 1" vacuum at the end of the pull indicating there is a small restriction. The only issue with jumping to a 102mm tbody, is you may end up with a lean hole during tip in throttle transition. If you have the ability to adjust your accell enrichment tables you can tune around it. Also, as someone else mentioned, if the intake opening is smaller then the Tbody you'll have to open it up too.
Very important info on the possible lean hole during tip in throttle position. Thanks. I am running the Merc PCM555 so that would require a visit to Dustin Whipple to sort out the fuel tables if a problem. I was hoping to just add some fuel pressure to handle the change.
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Old 03-02-2014, 03:35 PM
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So there is a benefit? Interesting. What is your red line set at?
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Old 03-02-2014, 08:36 PM
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Originally Posted by Keith Atlanta
So there is a benefit? Interesting. What is your red line set at?
For a stroked motor there apparently is a benefit. Is yours stroked? My red line is 6000 rpm, my power peak is 5300-5400 rpm but my best speeds have been at 5800 rpm with labbed 28P Bravo. Working on dialing in a BBlades labbed 30P Bravo to run at 5400 rpm but need to refresh the engine first before grinding any more metal.
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Old 03-02-2014, 08:52 PM
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Refresh? How many hours on that thing?

(No, I am not stroked, .030 over with a little porting to the Raylar heads. I stopped the dyno at 5800. It was still making power and still pulling. LOL, I didnt like the dyno room experience - kinda stressful)
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