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Marius850R

Upgrade N/A Cams , Only Intake Cam Or Upgrade Both Int/Ex On My 850 T5-R

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Hey just installed my N/A intake cam , i was wonder to get more performance out of them , can i advance or retard one of them , i kept my turbo exhaust cam , when installed both are on timing marks .

any suggestions ???

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Hey just installed my N/A intake cam , i was wonder to get more performance out of them , can i advance or retard one of them , i kept my turbo exhaust cam , when installed both are on timing marks .

any suggestions ???

Double post huh? Retard for high end gain and advance for low end gain. Have you read this thread yet? Read the first page.

Edited by Johann
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Double post huh? Retard for high end gain and advance for low end gain. Have you read this thread yet? Read the first page.

my bad .... i read this tread since i started the tread ! i was more looking for what people set their cams ( as degrees on intake and exhaust ) and for who installed just like me only intake cam and still have the exhaust turbo , what degres they use with best results ....

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I bet with an R manifold and a nice sized turbine wheel you're in the 1.1:1 range...

While I agree with your assessment of EBR overall (and btw it would appear trbicks tech discussion is leaking over here somehow.:lol:), the above is oversimplifying to some degree.

A low ebr can also just mean both the cold side and hot side are equally undersized, or that exhaust flow throught the port is crappy enough that all of the pressure drop is across the port/valve seat. In other words those modifications might make EBR closer to 1:1, but power output might stay the same or even drop. That is the wierd thing.

It's a value that needs to be evaluated systemically and not as a single attribute...

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While I agree with your assessment of EBR overall (and btw it would appear trbicks tech discussion is leaking over here somehow.:lol:), the above is oversimplifying to some degree.

A low ebr can also just mean both the cold side and hot side are equally undersized, or that exhaust flow throught the port is crappy enough that all of the pressure drop is across the port/valve seat. In other words those modifications might make EBR closer to 1:1, but power output might stay the same or even drop. That is the wierd thing.

It's a value that needs to be evaluated systemically and not as a single attribute...

Yeah that was a super simplistic explanation, I doubt it really happens exactly like that in the chamber. But it explains the concept of reversion pretty well.

From having the valves out and hitting these ports around the seat on a couple heads with a die grinder, I think you are right on the money with the valve/port idea.

As far as power dropping, I think that would really depend on whether there's reversion going on, and the improvement in exhaust side flow overall should produce some power gains at the same boost levels without even bringing EBR into the equation.

The 18T is about between a 60 trim T3 and Super 60 T3 I think, and at 15 psi in an 850 it should be absolutely in the meatiness of the compressor map.

What this EBR number makes me wonder is if the angle-outlet housing design makes the post-turbine flow good enough that it can really keep the manifold pressure in check. The wastegate port is pretty large and completely unshrouded, the turbine housing outlet is about 3" inside diameter (or a little larger). I really think that turbine housing is an overlooked gem to a lot of folks :)

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As far as power dropping, I think that would really depend on whether there's reversion going on, and the improvement in exhaust side flow overall should produce some power gains at the same boost levels without even bringing EBR into the equation.

I am saying there's a good chance it won't, actually.

The concern is effective VE. VE is reduced when exhaust gases with low O2 content take up space fresh intake air could have. This is charge dilution and reversion is only one cause of it, and turbine backpressure is only one cause for reversion. Not only that but changing the housing or wheel will actually change the hotside's efficiency, maybe for good, maybe for bad. Certain wheels work better with certain housing A/R's and bigger is not always more efficent, and if you are going to talk about EBR you need to include turbine efficiency in the equation. Add to that the boost curve will change in a way that may, or may not, compliment the engine's natural VE.

IMO to get to 1:1 EBR with an 18t or whatever, you'd just have a laggy turbo that's still only maybe cabable of 300whp. The potentialy hasn't increased, all you did was reduce some thermal stress and trade it for some lag. It's a mismatch.

I am saying there's a good chance it will, actually.

The concern is effective VE. VE is reduced when exhaust gases with low O2 content take up space fresh intake air could have. This is charge dilution and reversion is only one cause of it, and turbine backpressure is only one cause for reversion. Not only that but changing the housing or wheel will actually change the hotside's efficiency, maybe for good, maybe for bad. Certain wheels work better with certain housing A/R's and bigger is not always more efficent, and if you are going to talk about EBR you need to include turbine efficiency in the equation. Add to that the boost curve will change in a way that may, or may not, compliment the engine's natural VE.

IMO to get to 1:1 EBR with an 18t or whatever, you'd just have a laggy turbo that's still only maybe cabable of 300whp. The potentialy hasn't increased, all you did was reduce some thermal stress and trade it for some lag. It's a mismatch.

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my bad .... i read this tread since i started the tread ! i was more looking for what people set their cams ( as degrees on intake and exhaust ) and for who installed just like me only intake cam and still have the exhaust turbo , what degres they use with best results ....

My mistake, I didn't mean for that to come off cock like. Did you read that pdf that lookforjoe has from QBM? I think someone posted a link for it somewhere on here. I know it wasn't for NA cams, but QBM said that they found the best gains between 2 and 3 degrees advance on both I and E cams. I have the file in an email if you want it.

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I've been putting off playing with the cams for some time now but finally had a chance to do it yesterday.

I'm running both intake and exhaust NA cams and didn't actually check the cam timing when I installed them with the 35r, Nira etc.. I simply used the same settings that they were set to when the motor was built. I vaguely recall telling them to retard the cams for more top end.

Checking with the QBM tool, the intake cam was at +4 and the exhaust cam -2. I left the intake cam and simply advanced the exhaust cam to +3 or +4 degrees. WOW. The off boost throttle response is improved 10X. The AFRs are now a bit leaner but are still safe from what I could see. It has been raining this afternoon so I couldn't do any full boost pulls, but will be doing so the first chance I get. I'll also be doing some logging to see more whats happening with everything.

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I've been putting off playing with the cams for some time now but finally had a chance to do it yesterday.

I'm running both intake and exhaust NA cams and didn't actually check the cam timing when I installed them with the 35r, Nira etc.. I simply used the same settings that they were set to when the motor was built. I vaguely recall telling them to retard the cams for more top end.

Checking with the QBM tool, the intake cam was at +4 and the exhaust cam -2. I left the intake cam and simply advanced the exhaust cam to +3 or +4 degrees. WOW. The off boost throttle response is improved 10X. The AFRs are now a bit leaner but are still safe from what I could see. It has been raining this afternoon so I couldn't do any full boost pulls, but will be doing so the first chance I get. I'll also be doing some logging to see more whats happening with everything.

i am only running the intake n/a + 4 degrees and pretty happy tomorow i will advance my exhaust and see the difference ...

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I've been putting off playing with the cams for some time now but finally had a chance to do it yesterday.

I'm running both intake and exhaust NA cams and didn't actually check the cam timing when I installed them with the 35r, Nira etc.. I simply used the same settings that they were set to when the motor was built. I vaguely recall telling them to retard the cams for more top end.

Checking with the QBM tool, the intake cam was at +4 and the exhaust cam -2. I left the intake cam and simply advanced the exhaust cam to +3 or +4 degrees. WOW. The off boost throttle response is improved 10X. The AFRs are now a bit leaner but are still safe from what I could see. It has been raining this afternoon so I couldn't do any full boost pulls, but will be doing so the first chance I get. I'll also be doing some logging to see more whats happening with everything.

Curious to hear your results. I'm running +4º Exh 0º int. I'll advance my intake if your results are positive. What about egt's? Does the 35r flow similar to my 20g?

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Curious to hear your results. I'm running +4º Exh 0º int. I'll advance my intake if your results are positive. What about egt's? Does the 35r flow similar to my 20g?

I think the 35r flows a bit more.

35R002.jpg

I don't have egt right now but am waiting to hear back on a price of the Nira EGT probe.

I planned on retarding the intake cam a bit to see what happens, but I need to test out the current configuration before I make any more changes.

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I've been putting off playing with the cams for some time now but finally had a chance to do it yesterday.

I'm running both intake and exhaust NA cams and didn't actually check the cam timing when I installed them with the 35r, Nira etc.. I simply used the same settings that they were set to when the motor was built. I vaguely recall telling them to retard the cams for more top end.

Checking with the QBM tool, the intake cam was at +4 and the exhaust cam -2. I left the intake cam and simply advanced the exhaust cam to +3 or +4 degrees. WOW. The off boost throttle response is improved 10X. The AFRs are now a bit leaner but are still safe from what I could see. It has been raining this afternoon so I couldn't do any full boost pulls, but will be doing so the first chance I get. I'll also be doing some logging to see more whats happening with everything.

That's awesome. I can't wait to hear more of your results when you can push it. Did you use NA sprockets or swap your turbo sprockets onto the NA cams? Does having both cams adjusted to +4ish concentrate the power band in the low end? I'm going to be getting my cams in the mail soon, got all my new tools and the timing belt kit will be ordered soon so I get the motor in time to take off the valve cover.

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I think the 35r flows a bit more.

35R002.jpg

I don't have egt right now but am waiting to hear back on a price of the Nira EGT probe.

Just a little.....

:lol::lol: :lol:

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