Power limits by part
 

So. Intro thread done. Lurked for long enough.

I wanted to know what parts will need changing at when for my build, so i made this list. There is a lower and upper limit because, obviously, usage type affects life. Trackdays vs driving like your nan, etc

This is mainly so i can work out what power outputs are realistic, can set a budget, and start pulling the trigger on parts.

Would you veterans change anything? How off am i, country mile? Nail on head?

Thanks!



Part-----------------------Lower limit-------Upper limit

1.6 power, at wheels-------------------100
1.8 power, at wheels-------------------115
1.8 VVT power, at wheels--------------130

1.6 injectors-----------------140----------------150
6” (<1994) diff--------------100----------------175
1.6 clutch--------------------150----------------160
Cooling system--------------150----------------200
1.8 injectors-----------------170----------------180
1.8 clutch--------------------180----------------190
1.6/1.8 Conrods-------------225----------------250
5 speed gbox----------------225----------------275
Pistons (1.6?/1.8?)----------250----------------280
Fuel pump-------------------280----------------320
Oil pump---------------------300----------------350
6 speed gbox----------------325----------------400
7” (1994->) diff-------------350----------------400

EDIT: All in wheel HP!

There's your problem.

Pretty sure 1.8 Pistons can hold more than that

I guess it mostly depends on tire for drivetrain parts and tune for engine parts...

Axles let go around 400?
I know a few 1.6 rear ends on some 250hp cars too. Those things are weird. Some let go on stock power, some never die.
PPF's don't like a ton of power as well. Same with diff carriers.
Then there's the stock harmonic balancer.

Anyone have u-joint or drive shaft failures?

Thats pretty damning, ha.

Would you say that its accurate enough if done by the crank? Id assumed that everyone quoted wheel hp because of how dyno's work etc.

If i can get some better numbers ill update this, it could be a half decent resource. It took me ages to find it all...

Curly means that torque is the destructive force, not horsepower.

-Ryan

I really think pistons are stronger than they get credit for. It's just that very few people are dumb enough to install forged rods and leave the pistons stock. I put 25k street miles on my car at 332whp/303wtq before it was totaled and the stock pistons were still going strong.

I'd drop fuel pump down a bit, I think pretty much everyone over 250whp is running an aftermarket pump. I feel like mine is showing signs of struggling at 200whp. They're cheap and you don't want to find out that the stock one can't keep up when you're at peak power/boost.

The stock coils should probably join the list as well. Maybe 225whp-250whp.

Overall that's a good list.

Yeah if you've read around a bit on the forum, you'll realize it's "All in wheel FT/LBS!"

Some of the parts don't really need to be on the list either.

This can be calculated:

1.6 injectors-----------------140----------------150
1.8 injectors-----------------170----------------180

Who runs this little power...

1.6 clutch--------------------150----------------160

These are either glass or invincible. Replace it regardless.

6” (<1994) diff--------------100----------------175

This should be taken care of before/during turboing. Not based on power.

Cooling system--------------150----------------200

It is based a good bit on power. The more power you're making the more waste heat you're going to be putting into the coolant the more heat rejection capacity you need. Its also based on usage though. Some people can easily be running towards the upper limit of what the stock rods can take and be fine in their particular usage with the stock radiator and no re-route, IE they have no a/c, only see at most 3 seconds of boost at once, and live in the north.

^also dependent upon ambient temp/location in the world.

It matters if you are just doing a 10 second blast on the highway or a 25 minute session at the track.

TBF i guessed this one a bit. Sensible range? It seems so from what i have read, and i wanted to include it if just for completeness sake. Everything else is 1st dregree reserach from this forum.

I had another read of that link fooger, nice writeup. Nice to know how much HP i can afford...



Part-----------------------Lower limit-------Upper limit-----Unit (@wheel, unless rpm)

6” (<1994) diff---------------90----------------250---------lbs.ft
1.6 injectors-----------------140----------------150---------hp
1.6 clutch--------------------150----------------160---------lbs.ft
Cooling system (water)-----150----------------200---------hp
1.8 injectors-----------------170----------------180---------hp
1.8 clutch--------------------180----------------190---------lbs.ft
Ignition coils-----------------225----------------250---------hp
1.6/1.8 Conrods----------225/7500----------250/8000------lbs.ft/rpm
5 speed gbox----------------225----------------275---------lbs.ft
Cylinder head bolts----------Unknown, Above 250---------lbs.ft
Crank pulley/HB----------250/7500----------300/8000-----hp/rpm
Pistons (1.6?/1.8?)----------250----------------300---------lbs.ft
Fuel pump-------------------225----------------275----------hp
Oil pump------------------280/7500----------320/8000------hp/rpm
6 speed gbox----------------325----------------400----------lbs.ft
7” (1994>) diff--------------350----------------400----------lbs.ft

Half shafts---------------------Stronger than 7" diff
Propshaft-------------------Likely stronger than 7" diff
Crank/Block-----------------Unknown, above 500lbs.ft
Main bearing caps----------Unknown, above 500lbs.ft
Valve float(1.6?/1.8?)-------7500--------------8000---------rpm
Intake cam VVT--------------7400--------------7500---------rpm

PPF ?
Cooling system(oil) ?

1.8 axles break well before the diff, now what I dont know is if MSM axles break before the diff.

That is the first time i have seen mention of a VVT cam having an issue with high rpm... Has anyone experienced any sort of failure of the intake cam above 7500? Do we have any means to replace, reinforce, or otherwise rectify this issue?

Only reason I ask is because i will be using a VVT head on my next setup. i would like to address the issue ahead of time instead of having to fix it later

Its not above 7400rpm, its the area around 7400rpm. VVT head is totally cool with running 7500-7800 it just doesnt like the rpms near 7400ish because of harmonics. If you go searching back theres some old posts from many years ago on mnet about exactly what breaks. I know Sav told me when building my engine that the supretech valve springs took care of the issue entirely.

Ah, I got ya. Thanks for the quick update.
Andrew is building my engine as well, so this issue will be taken care of. I am still going to research failures for piece of mind.

My 93 is on 90k, I think its done about 20k of that boosted.

1.6 Viscous diff is quiet as a mouse.

5 spd box is kaput, dead, it is an ex-gearbox.

Just goes to show, er, something!

Question about cooling limitations. I am finishing a turbo build but havent addressed cooling yet. I am in the North East so outside temps shouldnt be above 60 for the next 5-6 months. Will I still have heating issues? Since it is the end of the season the car should only see 1 more autox before next year. Can I hold off until spring for street use? Car will have roughly 200 whp.

I broke my 1.6l diff in a parking garage no where near max TQ in 1st gear. So I think the 1.6L diff is just YMMV, be warned. lol.

These diffs seem a bit of a gamble! Theres gotta be some sort of random manufacturing oddity that makes the failures so sporadic. Or maybe they are super sensitive of not having their oil changed, i dunno. Ivw widened that range up, as well as a few other tweaks.

If anyone knows the limits of the half shafts, oil/coolant and the PPF, that will (should?) finish this off. Unless anyone knows different for anything else. Ive made my choices for power now.

Part-----------------------Lower limit-------Upper limit-----Unit (@wheel, unless rpm)

6” (<1994) diff---------------80----------------250---------lbs.ft
1.6 injectors-----------------140----------------150---------hp
1.6 clutch--------------------150----------------160---------lbs.ft
1.8 injectors-----------------170----------------180---------hp
1.8 clutch--------------------180----------------190---------lbs.ft
Ignition coils-----------------225----------------250---------hp
1.6/1.8 Conrods----------225/7500----------250/8000------lbs.ft/rpm
5 speed gbox----------------225----------------275---------lbs.ft
Cylinder head bolts----------Unknown, Above 250---------lbs.ft
Crank pulley/HB----------250/7500----------300/8000-----hp/rpm
Pistons (1.6?/1.8?)----------250----------------300---------lbs.ft
Fuel pump-------------------225----------------275----------hp
Oil pump------------------280/7500----------320/8000------hp/rpm
6 speed gbox----------------300----------------350----------lbs.ft
7” (1994>) diff--------------350----------------400----------lbs.ft
Propshaft-------------------Likely stronger than 7" diff
Crank/Block-----------------Unknown, above 500lbs.ft
Main bearing caps----------Unknown, above 500lbs.ft
Intake cam VVT--------------7400--------------7500---------rpm


Half shafts-------------------300?---------------???----------lbs.ft
PPF---------------------------???----------------???----------lbs.ft
Oil cooling reqd-------------???-----------------???----------hp
Reroute reqd----------------???-----------------???----------hp