Fuel wise i'm set and was wondering if anyone knew
what the stock connecting rods can handle before they
snap. I was reading on gm's site that they experienced
catastophic failure at 288 hp at about 4400 rpms.
So I'm wondering if it can survive being properly tuned
between 235 to 250 hp safely???? Or should i go easy on
her till i can find internals (WAY down the line). Opinions
comments advice or any comment at all welcome
The problem with GM's numbers is that the 283 hp breaking point was at the crank. I highly doubt that you'd be measuring your hp after any future upgrades with crank hp, rather than wheel horsepower, so you somewhat have to guess what the lack of efficiency is on your drivetrain between the wheels and crank. Also, with 283 chp being the breaking point, that doesnt mean that 282 chp would be fine for a daily driver, Id probably set a little bit more of a conservative distance from the breaking point.
that makes no sense. It had a vilonet failure at 288 crank hp
isnt suncavi and hypsy at like 300 whp on stock blocks. 288 is something like 240 230 whp BS most cars make that at like 5 psi.
"
Kick azz is my boost hero!!! 
"
GM's numbers were way off cause yes there are a few on the org with stock blocks and hitting 300+ whp
just build it and run it till it blows
The one, the only, ME.
Quote:
that makes no sense. It had a vilonet failure at 288 crank hp isnt suncavi and hypsy at like 300 whp on stock blocks. 288 is something like 240 230 whp BS most cars make that at like 5 psi.
GM got that 288 on strait nitrous... and a dry system at that... boost is nearly as stressful as nitrous.. that explosion that it makes in the cylinder puts extreme strain on the connecting rods.
tune it right and dont beat the ever living @!#$ out of it and you will be fine.. ii wouldnt try and push over 275whp.. people have done it, but i wouldnt risk it.
Thats basically why my target was 235-250 whp.
I want to get good numbers but have it run reliable for
a year or maybe 2. I know this is a contradiction
in terms but hey i can hope. I was hoping to dip
into the 13's a decent amount.
Anyone else with any tips/ideas/experience.
i cant go into detail yet cause im not fully satisfied but the motor will hold up to at least 302WHP
i aint got a clue to what that is at the crank...guessing 350 or so. but thats the mark ive got so far. but again....no details!
I used to race cars, now I race myself.
5K PB: 24:50
10K PB: 54:26
you cant put a exact number on a breaking point on a motor. Many things can have a great deal of the turn out on your motor. Like how much wear there is, how well you maintain it, how you tune it, and so on and so forth. Basically dont expect it to take much cause it a strong motor but it wasnt designed to be boosted without some over haulin. just think of it this way would you rather push its limits and blow the motor to hell or would you rather build it up and know what it can take with the proper tuning. thats how i look at it
id rather keep playing till i find some explosive limits. thats half the fun of racing....not knowing if you've got the stronger car or the most reliable
I used to race cars, now I race myself.
5K PB: 24:50
10K PB: 54:26
John H [Cavalierkid wrote:]Quote:
that makes no sense. It had a vilonet failure at 288 crank hp isnt suncavi and hypsy at like 300 whp on stock blocks. 288 is something like 240 230 whp BS most cars make that at like 5 psi.
GM got that 288 on strait nitrous... and a dry system at that... boost is nearly as stressful as nitrous.. that explosion that it makes in the cylinder puts extreme strain on the connecting rods.
tune it right and dont beat the ever living @!#$ out of it and you will be fine.. ii wouldnt try and push over 275whp.. people have done it, but i wouldnt risk it.
This is true. Truly on boost no one really knows what the breaking point is yet. 300 crank horse power can be done.
FU Tuning
As John H and ^he said, they were nitrous.
But here was a tid bit I see nobody mentioned. The numbers were GROSS not NET since these #s had no type of accesory on them. So in reality you are looking at lower #s NET about 20HP less then the theoritical 283HP on nitrous.
So be careful either way.
>>>For Sale? Clicky!<<<
-----The orginal Mr.Goodwrench on the JBO since 11/99-----
ooooo well then. now that I think of it has ANYONE blown a properly tuned stock motor. I think even us orgsters underestimate this motor. also whats the first thing to upgrade on the motor its the rods right. there the first to go.
"
Kick azz is my boost hero!!! "
This is why i I was asking your opinions
wanted to see how everyone was standing up
to what amount of punishment. And as far
as i can tell my 235-250 mark sounds like a
fairly good target from everything i hear.
My $.02:
In the Eco, as on most of the engines in this segment, the weak point is the powdered metal con rods. It's been our experience that 300 HP (engine) is a safe limit. 'Safe Limit' meaning: run it as high as that, but do not exceed.
We are typically conservative in what we state as safe limits, for, as mentioned in this thread, there are many external factors that we cannot control (detonation, excessive RPM, poor tuning, etc etc) that can all affect this threshold. Nonetheless, this 300HP mark has proved to be a dependable number for some years now. Some tuners can tiptoe very effectively and exceed it, but they have the instincts and knowledge to do so. On the other hand, some overconfident brutal types can break an anvil! It's all in the execution.
Yes, GM's numbers were achieved using Nitrous as compared to boost, so they will be skewed low to some degree. The essential difference between Nitrous and boost are the way they produce power increases:
1. Nitrous is sudden in its application, whereas boost is progressive. Instant pressure rises are harder on parts than gradual ones.
2. Nitrous achieves most of its power gain via increases in cylinder pressure, whereas boost increases power more by increasing the length of the power cycle, thereby achieving 'work' on the crankshaft for a longer period of crankshaft rotation.
Always remember, the combustion event is not so much an 'explosion' as a controlled burn. It moves away from the point of ignition at the spark plug, and 'burns' throughout the entire air-fuel charge until it reaches the piston, which is when cylinder pressure falls away, and effective power production on that cycle begins to ebb. The denser charge of the boosted engine takes longer to burn than the much faster pressure rise of the nitrous engine. They both increase power, but in substantially different ways.
Bill Hahn Jr.
Hahn RaceCraft
World's Quickest and Fastest Street J-Bodies
Turbocharging GM FWD's since 1988
www.turbosystem.com
^^^the legend has spoken.
I would not call 300hp "safe" by any means -- that is pushing it -- really pushing it -- it really depends on how much you need a running car i would say 250 and under you could consider safe but it all depends on your tune of course i would definently suggest to keep an eye on a pyrometer if you are going to run that much boost -- make sure the engine is not running too hot -- also make sure the car has a good tune on either a wideband or dyno -- the engine temp in some cases is more important then your air/fuel ratio -- meaning you can still cook your pistons on a 10.5 - 11.5:1 air fuel ratio
04 ecotec LS Sport wrote:I would not call 300hp "safe" by any means -- that is pushing it -- really pushing it -- it really depends on how much you need a running car i would say 250 and under you could consider safe but it all depends on your tune of course i would definently suggest to keep an eye on a pyrometer if you are going to run that much boost -- make sure the engine is not running too hot -- also make sure the car has a good tune on either a wideband or dyno -- the engine temp in some cases is more important then your air/fuel ratio -- meaning you can still cook your pistons on a 10.5 - 11.5:1 air fuel ratio
Truly no one can say. The limits have not really tested.
Bill made a very good post. Set-up is always going to play a factor. When I say set-up I mean, parts, tune everything!!!
FU Tuning
Yeah i understand this which is why i'm
being conservative with my target of 235-250.
I have gotten alot more responses to this
question than i expected and alot off good opinions
and advice.
Feel free to post more.
And to those that have already posted
Thanks
