You thought the I5 was strong??

[prj]

550 chp is a lot of power on a stock internalled 2.2L

rods are done before that

It will do 550hp on race gas with stock rods easy all day long.
The key ingredient here really is very high octane race gas. I think you can make even 800hp from an I5 on race gas and stock rods. On race gas the main danger comes from metal fatigue and failure due to high RPM, rather specific output on the I5.

[my2000apb]

over 400 whp gets pretty scary on pot metal rods

[prj]

over 400 whp gets pretty scary on pot metal rods

Have you considered the fact that after tuning about 80 project cars on I5 engines I do know what I am talking about?

[my2000apb]

Have you considered the fact that after tuning about 80 project cars on I5 engines I do know what I am talking about?

yes i understand that, you also have to understand there is only so much magic computer tuning can do to the strength of the connecting rod

[prj]

yes i understand that, you also have to understand there is only so much magic computer tuning can do to the strength of the connecting rod

You are throwing statements left and right without delving into anything.

Horsepower is meaningless.
The stock rods fail mostly for two reasons:
1. Bending due to detonation.
2. Breaking due to high RPM.

Nothing else. On pump fuel, I have tuned PLENTY of cars to 600nm, some of them running for 2 years on pump fuel of varying quality (alternating 95 RON and 98 RON when engine was tuned on 98 RON) and absolutely not a single failure.

Now let's do some math. 600nm at 7000 rpm is 590hp.
This is on pump fuel. On race fuel or E85 I am happy running 750nm through these rods.
Again, let's do the math - 737 hp.

Your statement about "magic computer tuning" is insulting. Maybe you should go back to carburetors instead? I actually take great pride in the fact that I have a very good understanding of the otto engine regardless of the management system used.

[my2000apb]

motoronic or standalone?

[prj]

motoronic or standalone?

All of those cars on motronic, if you are asking about that.
Btw, my first post was directed at the OP and the article in the OP.

[my2000apb]

the magic computer comment was not meant to be insulting, im sorry if it was. im jsut not totally convinced as ive seen plenty of them and i mean plenty of them loose rods ~400whp, youre probly a better tuner for sure from teh sounds of it, but you gotta admit lots and lots have popped lower than that on chip tunes

[prj]

the magic computer comment was not meant to be insulting, im sorry if it was. im jsut not totally convinced as ive seen plenty of them and i mean plenty of them loose rods ~400whp, youre probly a better tuner for sure from teh sounds of it, but you gotta admit lots and lots have popped lower than that on chip tunes

I have seen holes in the block on stock turbos. Completely bent rods on RS2 turbos, but does that mean it is a problem with the engine?

Any engine is going to let go, if you dump tons of boost, advanced timing and no fuel in there.
Like spraying dry nitrous without fuel increase for example. BOOM.

All this talk about rods is because people think that buying some chip off of eBay or the internet and then sticking it into their car which is probably not even close to the same configuration and has fuel pressure tapering or other issues is a great idea.

About 1 in 10 cars I tune does not have any issues. The rest all require repairs and fixing of problems first. Now imagine what happens if the owner is not aware of those issues, plops in a couple chips for 25+ psi, and his car goes lean as hell at full boost.
Again, BOOM, bent rods, and so on.

The only actual problem with the rods is, if you fit a big turbo there, and raise the rev limiter to 7500 rpm or so, then after 20 years in service they get tired, and they can just snap due to the fact that you start using the car at high RPM.
Of course if you are not using race gas, then the rod needs to be able to take some detonation. Now the stock rods with a real time map can take detonation even at 600nm. That's about 28-30 psi btw on a stock head.

[my2000apb]

oh yes i understand that for sure, the more you turn the wick up, the more things that werent issues before are now major issues

i was more jsut skeptical as the norm limit in america is ~400whp before its a ticking time bomb, and you number was a bit higher

not meaning to bash, was more jsut surprised by it

[prj]

The point is, you are talking about power, but it's not power that matters.
It is the PCP (peak cylinder pressure), which you could say is torque.

Most power curves are spike then taper on the I5.
if you run it more linear, and limit the torque, then you can even run a GT30R, still make those 400 whp, and not have a ticking time bomb.

But you will need to stop at about 26-27 psi, and just hold it.
Whereas with upgraded rods you could easily run 32 taper 30.

[prj]

Btw, my number was in regards to the first post.
Where they ran a stock engine and looked how long it will go until it lets go.

They had a very controlled environment, with basically a completely flat torque curve after it's on boost and also race gas on which the engine never knocks.
This is not representative of what people would ever run on the street. So you can't at all compare the numbers between 118 race gas and pump gas.

I also think that it is a very good idea to stop at 500chp(400whp)/600nm at the crank on the I5 on stock internals. Anything over that is eventually asking for trouble.
But for laboratory purposes with a straight torque curve and race fuel, this is for sure not even close to the limit of what the I5 can do.

[my2000apb]

goodpoint

[banedd]

Thing is, that motor made 1203hp or 251.66hp/l with 118 octane race gas on stock internals with gapped rings. A 20v I5 will easily eclipse 553hp (the equivalent hp for 2.2L motor) using 118 octane gas and completely stock internals. In fact, with a set of connecting rods thrown in, a 20v I5 will make 800+hp running 118 octane gas without even sweating!

The LS is a good, strong motor that GM has been perfecting for 50+ years. It has a huge displacement advantage over the little I5 so it's not that surprising to see it make 1,200hp.

[banedd]

I agree with prj. Most people blow their motors up because they don't know what they are doing and because they run them with zero safety margin with regards to timing and fuel delivery. 118 octane gas makes a massive difference as it virtually eliminates knock completely. I've seen a completely stock 10v Audi block with 7A 20v head on it make over 500whp in an Audi 5000 running 112 octane race gas on a dyno. Conversely, I've seen a 20vt grenade at 380whp due to lean run conditions and too much ignition advance but that can hardly be blamed on the internals of the motor.