HP limit of non turbo internals

[NOSLO2PT0]

I hate to ask this question as it sounds so noobish. But, I looked all over and didn't really find anything to my liking. I'm at a cross-road with my daily driver. I need a bottom end for it. Nothing special, just a simple 7 bolt 1G turbo car. Car will just be running 20psi on a 16G.

My question is...a local has a complete 6 bolt N/T longblock for sale. What is the max HP the stock piston ring-lands can take. What has anyone made HP wise on stock internals for a N/T motor?

If anyone can point out a few threads with this info, that would be great.

 

[92tsifwd]

It is more about at what amount of detonation will destroy the engine? One overboost was all my 1g 7 bolt n/t engine lasted for. It broke all four piston's ring glands & spun two rod bearings. Now if it were tunned for 25psi it may have lasted longer. My recamendation is to get it if it is a 6-bolt & put some good turbo pistons in it or better yet some forged ones.

 

[bastarddsm]

I have put 40k abusive miles on mine. I ran 25psi daily on e85 with 450cc injects and lots of timing. It has been detonated lots. I do everything that your not supposed to do, and it holds up. My car weighed 3300 with me in it, I trapped 107 like this. I figure thats about 350 crank hp.

I'm going back to the strip with a held closed wastes gate china gt 16g, 750cc inj, and E85, I'll let you know what happens.

 

[92tsifwd]

I have put 40k abusive miles on mine. I ran 25psi daily on e85 with 450cc injects and lots of timing. It has been detonated lots. I do everything that your not supposed to do, and it holds up. My car weighed 3300 with me in it, I trapped 107 like this. I figure thats about 350 crank hp.

I'm going back to the strip with a held closed wastes gate china gt 16g, 750cc inj, and E85, I'll let you know what happens.

Were you running a knock sencor with the turbo ECU? That will help. Also E85 if tunned properly, has a higher resistance to detonation than reguler pump. What was your injector duty cycle at with 450's, 119% at 25psi? E85 takes 33% more fuel then pump to make the same energy. With 107mph trap you should be in the 12's with traction.

 

[NOSLO2PT0]

I have put 40k abusive miles on mine. I ran 25psi daily on e85 with 450cc injects and lots of timing. It has been detonated lots. I do everything that your not supposed to do, and it holds up. My car weighed 3300 with me in it, I trapped 107 like this. I figure thats about 350 crank hp.

I'm also on the Chi-town board that you posted your results on. I wouldn't be too proud of them, so I'll leave that info out of here. The 40k miles of daily driving wasn't my main point of the thread. The point was to see how much HP a N/A bottom end can take. The results you posted in that other thread didn't give me much insight to the answer of my question.

I still would also love to see your duty cycles at 25psi with those 450's. Maybe it's time to get something real to tune the car with to improve upon those numbers?

 

[bastarddsm]

I'm also on the Chi-town board that you posted your results on. I wouldn't be too proud of them, so I'll leave that info out of here. The 40k miles of daily driving wasn't my main point of the thread. The point was to see how much HP a N/A bottom end can take. The results you posted in that other thread didn't give me much insight to the answer of my question.

I still would also love to see your duty cycles at 25psi with those 450's. Maybe it's time to get something real to tune the car with to improve upon those numbers?

That's irrelavent to this thread. but my idc were only 109% peak. I run 55psi base fuel pressure, that makes my 450's like 590's.


Anyway, the n/t internals are the same as a turbo. the crank and rods are identical. The factory tech manual shows it. The pistons are higher compression, but they are just as durable. I have not broken one ringland yet. And you can see, I don't treat them lightly.

 

[92tsifwd]

That's irrelavent to this thread. but my idc were only 109% peak. I run 55psi base fuel pressure, that makes my 450's like 590's.


Anyway, the n/t internals are the same as a turbo. the crank and rods are identical. The factory tech manual shows it. The pistons are higher compression, but they are just as durable. I have not broken one ringland yet. And you can see, I don't treat them lightly.

I can garantee the n/t pistons are not as durable! Would you like to look at one? N/T's have the piston ring glands very close to the top of the piston which makes them very weak in the event of detonation. The factory turbo pistons, the ring glands are alot lower & run more piston to wall clearance and a looser ring gap, not to mention lower compression, & the block has oil squirters & a oil cooler resalting in a cooler stronger piston that can take more power.

 

[NOSLO2PT0]

That's irrelavent to this thread. but my idc were only 109% peak. I run 55psi base fuel pressure, that makes my 450's like 590's.

Assuming you are running a turbo fpr, which gives you a base FP of 37psi, running 55psi base actually turns your 450's into 548cc injectors, not 590's. Not sure how you are doing the match, but the calculator can be found here:

RC Fuel Injection

Anything over 100% IDC is basically irrelevant. the ecu just calculates a number as to what the IDC should be. Basically you don't have enough injector, as they are staying wide open during the entire run.

*edit*

My numbers are a bit incorrect. The 450s were rated at 43psi. So increasing from 43 to 55psi, your injectors are only going to be 508cc. Far cry from the 590cc you believe them to be.

 

[->PrOjEcTGS<-]

The pistons are higher compression, but they are just as durable. I have not broken one ringland yet. And you can see, I don't treat them lightly.

Be careful. They are not as strong as turbo internals!

http://www.dsmtuners.com/forums/newbie-forum/303988-nt-4g63-pistons-2.html#post151588207

 

[JEFFREYCASTGSX]

There's a member on here making high 400whp on a n/t 6bolt, but he tunes for 0 knock, truth is the n/t pistons aren't pistons that are designed to be hit with the hard detonation of a boosted motor, and keep in mind that the n/t doesn't have oil squirters(aren't needed anyways). Basically a n/t block can do as much as a turbo, but the pistons are the weakpoint.

 

[jrohner]

I say throw it in your car and go. Just be careful and log it to make sure there isn't knock. 2G's have a pretty conservative timing map so you should be OK as long as you have the base timing set correctly. You can always back the timing down a couple degrees too if necessary.

 

[dsm-onster]

The rings lands ar definately closer together. Which leads to fractures with minor knock at mediocre HP levels. We've pushed an n/t block to about 18psi with a small 16g and as soon as we started seeing knock, crack crack crack crack. for piston crowns had cracks on the rims. The problem isn't really the pistons ability to handle cylinder pressure properly applied, but the spikes from knock WILL eat them even at 25-30lb/min.

One think I noted is that the wristpins in our n/t motor wasn't as thick. The outer diameter is the same but the inner diameter is larger, making the wrist pin weaker. But I'd get the block any way if the price is right. Because it has the 6bolt rods (all rods are the same n/t or t for their respective year). Just factor in the cost to get turbo pistons and punching out/in the wrist pins.