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Old 06-14-2006, 12:05 PM   #21
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Quote:
Originally Posted by bandit
is there a Easy way to fix the LIM problem??
When you take it apart, measure the height and width of each head port, then compare it to the height and width of the LIM ports. Make them match. This will likely mean increasing the width and height of each port in the LIM by about a tenth of an inch. This amounts to a 10-15% flow restriction. This is assuming the L27 ports have the same issues the L67 Series 1 ports do. I think it'* a safe bet to assume so at this point, but measuring and posting your findings will be the key here.

S2 engines tend to be better matched from the factory. Dig up my old LIM porting topics and take a look.
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Old 06-14-2006, 12:05 PM   #22
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Quote:
Originally Posted by willwren
Gotta remember, Todd. You have a much higher flowing setup. An L27 isn't going to benefit that much from simply polishing head ports while removing very little material when he doesn't have a supercharger sitting up there stuffing air in, and his LIM outlet ports are actually smaller than the intake ports in the heads.

I seriously doubt if this type of work (as it'* described in this topic) would even be noticable without other supporting work done at the same time.

The port configuration differences between Series1 and Series2 are significant.
I agree they are very diffrent... On the LN3 and my L36 I noticed that the ports from the lower manifold could use some work...

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Old 06-14-2006, 12:18 PM   #23
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Quote:
Originally Posted by willwren
Gotta remember, Todd. You have a much higher flowing setup. An L27 isn't going to benefit that much from simply polishing head ports while removing very little material when he doesn't have a supercharger sitting up there stuffing air in, and his LIM outlet ports are actually smaller than the intake ports in the heads.

I seriously doubt if this type of work (as it'* described in this topic) would even be noticable without other supporting work done at the same time.

The port configuration differences between Series1 and Series2 are significant.
If we are just talking ports then sure, but to me, porting heads is doing the bowls, ports, runners etc...
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Old 06-15-2006, 04:18 AM   #24
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On some engines you can lose low end torque when opening up intake runners and ports. I'm not sure about the 3800. If it were me, I'd just swirl finish the combustion chambers and bolt on some roller rockers.
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Old 06-15-2006, 08:19 AM   #25
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Originally Posted by MACDRIVE
On some engines you can lose low end torque when opening up intake runners and ports. I'm not sure about the 3800. If it were me, I'd just swirl finish the combustion chambers and bolt on some roller rockers.
Whatever low end torque is lost, you just pick up dropping pulley sizes
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Old 06-15-2006, 09:34 AM   #26
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Quote:
Originally Posted by MACDRIVE
On some engines you can lose low end torque when opening up intake runners and ports. I'm not sure about the 3800. If it were me, I'd just swirl finish the combustion chambers and bolt on some roller rockers.
We already have roller rockers from the factory.
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Old 06-15-2006, 12:40 PM   #27
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Wilwren is correct. The biggest limitation on the Series 1 is the LIM; I compare it to trying to suck a Wendy'* frosty with a small straw. You can have the best ports in your heads, nevertheless, they will not build any energy and loose velocity due to the restriction and dead zones in the plenum. On the other hand, the Series 2 has a much better intake manifold and the entry in the port was design to keep the velocity and port energy more efficiently. There is no close compariosn in performance and/or flow between the Series 1 and 2 LIM'*.
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Old 06-19-2006, 03:25 AM   #28
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Quote:
Originally Posted by willwren
Quote:
Originally Posted by MACDRIVE
On some engines you can lose low end torque when opening up intake runners and ports. I'm not sure about the 3800. If it were me, I'd just swirl finish the combustion chambers and bolt on some roller rockers.
We already have roller rockers from the factory.
Don't you mean roller lifters? The 3800 comes from the factory with plain regular rockers right?
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Old 06-19-2006, 09:13 AM   #29
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Mac, the roller rockers started in 1993.
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Old 06-19-2006, 09:35 AM   #30
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Quote:
Originally Posted by willwren
Mac, the roller rockers started in 1993.

I was under the impression that the reason we're switching over to the Intense rockers is because the stock ones are not roller. Some how you guys left me out in the Nevada dessert without a map.

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