hey everyone, im hoping that i can get some opinions and advice from you in the next few days.

my mod list so far is:

kleeman k2 flash, pulley, headers, and downpipe
VRP CF airbox, python intake tubes and X-pipe
Fedor Dezyn 82mm TB and midsection exhaust
Custom made heat exchanger by Bell intercoolers (30"x6"x3.25")
Johnson CM30 pump and split cooling circuit

i have a custom tune day setup on september 28 and i need to choose a larger pulley. im using the kleeman 168mm now and im not sure if i should go with a 180mm pulley (ASP) or a 190mm (FD). i have to make this decision over the next few days as i need time to order the part, wait for it to arrive, and have it installed before the tuning day.

i know that the 180mm is an improvement with proper cooling, and that there are several members here that can attest to that. the main question i have is:

will it be more beneficial to go with the 190mm or is it overkill?
will it allow me to make more boost which in turn will make me more hp and tq?

Any advice would be very much appreciated.
thanks!

 

Go with the new 300mm (11.8" diameter) that will soon be coming out...haha.

 

The big problem with an extra-large pulley is its influence on efficiency of the SC. Increasing the SC RPM over the carefully engineered OEM efficiency value in parity with engine air-volume consumption will inevitably result in an exponential detuning the SC efficiency. In other words, there's a point where it makes so much extra heat relative to boost, that the resulting increase in IAT will retarded timing enough to counter-act any increase in boost. (regardless of altitude)

At a lower virtual altitude, increased IAT will lead to detonation sooner, hence the ECU's compensation of retarded timing. Therefore, the altitude at which you reside should be accounted for in your decision of pulley size. If you live at sea level, my advice would be to consider the smaller pulley, where as 3500+ft, you may want to look at the 190mm. Although IAT may not be largely influenced by altitude vs. pulley size, engine longevity will be a factor as you approach its stress yield. In other words, the M113 motor will produce more power at sea level relative to a motor at altitude (obviously), and you may want to consider a smaller pulley at lower altitude or a larger pulley at high altitude in order to safely avoid the engine's stress yield. Afterall, the closer you flirt with the stress yield of the system, the more risk you take in lowering engine life and reliability.

Larger pulley = increased IAT. Therefore, cooling system upgrades will be invaluable and required. Headers will also decrease the relative boost (seen pre-combustion) due to an increase in exhaust scavenging, resulting in less boost and therefore; advanced timing and more power. I would strongly advise upgraded cooling and headers (as you have done) - assuming you can achieve a tune that is capable of supporting these variables.

I am personally of the opinion that the 190mm pulley reaches too far out of the SC's efficiency bubble and is not worth the boost vs. heat that results. But if you are at a higher altitude and cooler climate, maybe you should go for it. But I think you are very closely approaching the limits of how far you should take it. How much do you trust your tuner?!?!

Good luck, I look forward to your results!

 

thanks so much for the info.

i live in the vancouver, bc area so im at or below sea level with a cooler climate.
based on that, do u think the 190 is ok? i think our temps are similar although we get less snow here and our winters are not as harsh. i want to make the most i can with my one shot at a custom tune. the pulley is the final piece to my puzzle.

i do not know if i will get this chance again. i wish there was some hard data out on the 190mm because id hate to go 180mm now and then find out a few weeks later that i should have gone 190mm.

as for the tuner, i trust him. he is the same person that tuned bassn_07 's car and we all know that on the dyno and at the track, his car is a beast!

 

tylersphile, excellent post.

jikjak, if it were me, I'd go with the proven results of the 180mm, instead of being a "pioneer" with the 190mm... and whatever resulting experiences that may bring (good or bad). YMMV.

 

I say go for the 190mm! People said the same thing that all you needed was a 172mm and anything bigger is not needed. Be the trend setter and pioneer .

 

I think people are looking at MM increase for power and % of pulley size increase. Not a lot of difference from a 180mm to a 190 MM % wise.

Do the math first and stop thinking in MM increase. 168MM to 178Mm is a lot larger % increase top spin the blower than a 180MM to 190MM..

 

DOes anybody make a 185 that way you can go 1/2 way.

JikJak your car is already a beast... so adding a 180 should be plenty. Can't wait to hear the supercharger whine when you pass me at 120mph again. It was sick last time the whole front of your car was lifted up!

 

Vancouver eh? That's where my car grew up! I just brought it back from there in april 09...

Side note: When I bought it (in Vancouver) I had a chance to drive around for a few days before heading up to 3500 ft in Calgary - and WOW there is a big difference in output in the two locations. My 178mm & mods bring my car back to just a little above sea level output levels at altitude... (but at the compromise of high IATs)

Check out this Compressor Map Thread and spend a few minutes to learn how to read it. It looks hard, but it's really pretty simple. The characteristics of this map will be remarkably similar to that of our M112 blower. Plot where you think you are now and where you want to go and keep an eye on IATs. Notice IAT exponential relationship to volume.

I'm hypothosizing you won't see a large difference in output between the two. Sure you'll see a little more power, but at the cost of a lot of extra stresses introduced to engine components and accessories.

IF you go for it, you should seriously consider FURTHER upgrading your cooling system. Nice work with the split IC system and HE upgrade, but the CM30 may fall short with a 190mm. You're capable of dissipate the heat appropriately, but the collection of it could be improved upon. Shy of upgrading the intercooler, I would do everything in my power to increase the volume of coolant moving through the system. CM90? Renntech's custom pump?... I would love to see a belt driven pump incorporated into a system... hmmmm...

Cheers!

 

i'd keep kleemann pulley over asp pulley....

 

if i lived near the tuner it would be easy to choose 190mm and if that didnt work for me then i can switch to 180 late and then drive over for a new tune.

unfortunately i dont have that luxury so i really have to be careful. i do want to roll the dice and go with the 190mm though. i just need to find out more before deciding.

 

Thx!

And just to further clarify the issue with the 190mm...

Lets assume with an OEM pulley, the compressor output temperatures (pre-intercooler) may be 195*F (for argument sake). The factory cooling is capable of pulling 35-40*away, bringing it down to a reasonable 155-160*.
Install a 180mm pulley and compressor output temperatures may be, say 210*F. An upgraded cooling system may bring it down 50 degrees to 160.
Now put a 190mm pulley on there and your compressor output temperatures will climb dramatically to, say 230*F. The cooling system no has to drop intake charge air temps down 70* to compensate (double the OEM designed specifications)! So the weak link is the ability to remove that heat, and as you know, our cars aren't very good at that even with an OEM set up.

Assuming you can increase the cooling capacity of the system, I would recommend you go ***** to the wall with the 190mm, but you may find it is very difficult to pull that extra temperature away. And if the cooling system fails at achieving proper intake temps, your ECU will pull timing to compensate.

That, to me, is the biggest issue you face. Solve the cooling problem, and you're laughing. It is a difficult bottle-neck to overcome in my opinion...

But on the other hand, you DO live in a good climate with reasonable temps to start with...

Let me know if you go through with it - I'll drive down and buy you a round of beers...

 

185mm would be a nice option to have!

i didnt realize the whole front end went up, how high did it go? hehe

 

thanks for the map. ive seen that before and i forgot about it.
its hard to make sense of it though but ill try my best to!

if the cm30 doesnt flow enough then ill definitely try a stronger flowing pump.
apparently its just about the same as oem but more reliable.

 

keeping the kleeman 168mm is definitely not an option.
i did the cooling and arranged the tune to make more power so i have to change to the larger pulley.

 

thanks!
heat is definitely the biggest problem i can run into.
i wonder if my cooling setup is good enough, and if not, would a rear mounted reservoir and a stronger pump do the job?

 

Most likely not. If you go with the 190mm you should have someone fabricate some SLR type coolers, if you want to do it right. They'll make your S/C more efficent with the 190mm, bring temps down, and increase air flow.

 

Just ADD 82mm TB, headers and port heads.. Then you can run 190, be cooler and make less boost. Then you have an efficiant, powerfull engine..

Now that is settled, I can sell my used 180 to the next buyer..

 

He already has 82mm and headers just not the porting.

Anyone tried a nitrous loop on the intercooler or maybe methanol injection ?

 

ASP 180mm seems to keep proving itself!

 

At what PSI would you recommend moving up in size? I'm sure he needs more boost just for the fact that he's still running a 168mm pulley, the question is how much more???? Data log your car Terence and see how low of boost you're running.

 

I wish i had one. If the 180 gives about 12-13lbs can our cars readily handle another 1-1.5lbs of boost?

 

I would say unless you are running custom intercoolers you are heading for heartache. The back end of the FI system is barely up to spec for the OEM pulley and very marginal for a larger one, for a 190 its beyond its means.

190mm and custom SLR type intercoolers should be a sweet match although look at the SLR ... their pulley is not that large - certainly not a 190mm unit.

So I would search for more efficiency rather than increase inefficiency.

 

ya, it would be nice to have some custom intercoolers, or better yet the actual SLR ones.

 

You could do it Terence, all you need to do is purchase a modified hood . Once you do that you should have enough room to make it worth while or pay 8k for the Kleeman setup. I once considered it but the mod fund didn't allow it . Does anyone know if the intercoolers below the SC would have to be modified or left alone?