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hi everyone I'm new to Pontiac solstice forum I just bought my 2007 Pontiac GXP about 2 weeks ago and I have the GM turbo upgrade,hard pipe, and intercooler sitting in my garage bought these items two months prior to the car was wanting to know what boost and max horsepower the stock internals can make...looked around couldn't find a straight up answer thanks :)
 

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wanting to know what boost and max horsepower the stock internals can make...looked around couldn't find a straight up answer thanks :)
'Cos there isn't a "straight up answer". There is no real hard limit, just a roll off of reliability. Having said that though, the general answer is thought to be that the stock internals can handle up to about 400hp at the crank. As with any figure though, this is NOT a guarantee and YMMV.
 

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Welcome to the forum! There are several members here running at several different levels of power, but from what I've gathered, it seems the LNF will run pretty steady to around 400WHP before needing heavier internals. I'm not an LNF owner so I could e wrong, but I'm sure someone else will chime in!
 

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Ha, TS beat me to it, I guess it 400 crank, not wheel.
 

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OK
TS is correct of course . .

For what its worth.

There was a running production change on the rods. Look for the thread on sintered rods for the 2.0. There is a concern that the later rods are less robust than the earlier rods.

There are a lot of cars running around with 300 - 325 WHP that are apparently as reliable as the stock 2.0 cars.

There are a number of cars in the 390 - 400 WHP range out there. Several of those have had issues with the syncros which is believed to be a result of the high horespower. Dave has stated that he believes that 400 WHP is the limit for a reliable 5 speed transmission.

The GMPP tune provides less peak torque for the automatic cars than for the 5 speed cars. There are a number of assumptions as to why this is the case, but there is also confusion. Some say that the auto is better able to deal with higher HP values than the 5 speed, but wonder why the factory limited torque. My personal opinion, and its only an opinion, is that it has more to do with shift quality and firmware in the transmission than its ability to handle the added power.

There is a body of people who believe that the axels are ok up to 400 WHP but that figures above that can lead to failures.

Resist at all cost mucking with the rod controlling boost. There are a number of posts looking at this as a road to power but most have either gone back to stock or given up on this path.

The best power mod is the GMPP tune or tune of your choice. Considerable "free" power to be had.

The only mod other than a tune that is proven to add actual HP is a high flow cat. By all means, get one.
 

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hi everyone I'm new to Pontiac solstice forum I just bought my 2007 Pontiac GXP about 2 weeks ago and I have the GM turbo upgrade,hard pipe, and intercooler sitting in my garage bought these items two months prior to the car was wanting to know what boost and max horsepower the stock internals can make...looked around couldn't find a straight up answer thanks :)
You don't want to run without a cat as I've heard/read that it will make the car smell like raw gas... I believe 25psi is the most boost, it can handle 30psi (or so I've read) but anything over 25psi is marginal without much of a return. If someone reads this with more experience, go ahead and correct me!
 

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Like the others said around 400.
On the stock turbo you don't want to push boost boost to high because it will be out of its efficacy range and just cause excess amounts of heat.
I am running the Hahn s20g on my stock long block at about 24psi without issue.
 

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To add to what Rob said.

This video does a good job of explaining the powered metal rods versus the forged rods and why they went to powered metal.


The guy in the video made my day. In 1984 a group I was with at Pontiac talked about snapping connecting rods like he talks about in this video. I know that the Tech Center had people working on it for years; they could get them to snap but were distorting the bore. That was the last I heard before I retired in 2000 and it looks like they perfected the cracking of them.

I do know that the testing that would have done on them would push the envelope and they're not going to break running with the GM tune.

The switch to powered metal would have never been done if they didn't perform as well as the earlier rods; because if they fail GM has to fix the engine and a blown rod means a new engine.

With that said if I were to put money into the engine to get 350+ hp I would change the rods.
 

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I believe all 2.0 LNF engines came with forged rods. The change to powdered was for the 2.4 engine IIRC.

If that is incorrect please let us know.
 

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I believe all 2.0 LNF engines came with forged rods. The change to powdered was for the 2.4 engine IIRC.

If that is incorrect please let us know.
I can only find that same change discussed too. Nothing about the LNF.

Here's another take on different rod types, suggesting the sintered rods are actually pretty good (see from 2:40 mark where the sintered rod is introduced):

(This was from the thread: http://www.solsticeforum.com/forum/f64/factory-le5-connecting-rods-please-read-66445/ )
 

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GM notes the pistons in the LNF should be changed at over 300 whp and that is the first recommended engine internal change. There are a lot of people over that with the stock pistons, but there has been the odd failure as well.


And I agree with the last couple threads above, the LNF has forged rods, the LE5 changed to the powdered rods.
 

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So did the early LE5 have forged rods before they went to powdered?
 

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I'll take forged over powdered metal any day. Why set your limits to close to stock if you are looking to build hp? Ford 7.3 guys hate powdered metal rods because they suck once you get a little past stock hp numbers and they are the first things to break. I like the reference he made to the 6.0. That serves as a better boat anchor than a motor unless you want to drop about 3-5 grand into the motor just to make it run.
 
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