Any fitment issues with the Mishimoto Oil Cooler?

You will have fitment issues with any upright square setrab core oil cooler in the intake duct unless you side mount the kid in front of a wheel. MAYBE the JacksonRacing long bar oil cooler can fit, but it's not something that I've tested.

I was looking on Harrop’s website at pulleys? Which ones are for our kit? I have a 95mm and 85mm pulley. The 85mm pulley makes the belt considerably easier to get on. I would imagine moving smaller would require a belt change. Does anyone have experience?

My 85mm hits 12ish psi. I believe Harrop runs a 65mm on their 2.1l time attack car. I’m assuming the 65mm maxes out the supercharger. What would be the optimum psi/size pulley? I understand that if speeds are too slow or fast then it is out of its efficiency range. Where is peak efficiency?

It seems that the 85mm is on the border of what should be done on 91. I pretty much am only running E85 now. Power is of course better, but I’m convinced the car doesn’t like 91. I’m going to do a second direct injector seal replacement with spark plug replacement this summer to optimize my engine health, but 91 might be too hot for 12 psi at sustained levels. If I was just using e85 then I would consider also slightly increasing boost if there was a sweet spot for efficiency.

On a stock engine I would be concerned with rod longevity on a smaller pulley, especially if targeting E85. I'm sure there must be compressor maps around for this blower, but consider that Cosworth overspin the smaller blower without seeming to hit any efficiency issues so long as the cooling is good enough, as this kit is.

Thanks. The question is what is considered small or what is considered a high boost pulley. 350hp and, more so the associated torque, is the limit. Supercharges tend to push less torque than turbos overall and less torque down low, so that changes things a bit. What is reasonable for the street is different than what is reasonable for the track. Many guys are running dual maps so they are less aggressive on the track. Some argue that the rods are weak, but it was the tune/detonation or oil starvation that actually led to rod failure. This is why some are pushing over 400whp on stock internals.

Flirting with the limits of the loads on the rods is not my goal, but I feel like 12psi isn’t near the safe limits on dedicated e85 motors for street use. It seems like most are looking at 20psi or more for a high boost pulley. Does that mean 14-15 is fine? Also, would 15 psi be a more ideal place for the supercharger to be at its stride or peak efficiency?

All I'll say is that given that Cosworth have analysed and therefore the strength of the rods:
The weakest link in the engine is the connecting rod which can bend if too much torque is applied too quickly. They can also break as it is a cast item. We have had the standard con rods analysed by Cosworth and agree with them that 280bhp is about the safe limit. That's not to say they can't withstand more, it just becomes a lottery.
We use BHP over here, not WHP. Their smaller pulley boosts power up to 300BHP and they won't guarantee it will survive. I know of a Harrop car that destroyed a rod at after swapping to a smaller pulley. Individual cylinder pressure tuning is somewhat key.

Horsepower is often quoted but torque is what breaks stuff. What is the torque level?

Perhaps this is better:
https://res.cloudinary.com/lagbv048w...sure_Chart.png

Perhaps your faith in my abilities is higher than it should be. What are we looking at?


Are these values for a stock car? Are the cylinder pressure lines not as complete in cylinders #2, #3 and #4 like it is for #1 because the lines are identical or not critical? FSF limit means what? How was it determined? How was the "max torque and power limit" line determined? What does it mean because the units are in pressure and not hp/tq? It seems the limits rise (non-linearly) with rpm, which favors supercharger curves more than turbo curves. There is a buckle limit of 105 psi from 5500-7000 rpms, which is flat/fixed, but it is the buckle limit of the rods or of what? Why doesn't that limit extend across the rpm range because the limit should be there at all rpms, and hitting that limit would be easier to achieve in some respects at lower rpms when piston speeds are lower.

The main thing to look at is the Buckle Limit (curved line with no points), which is the safe pressure threshold of the rods. Ignore the Cyl 1-4 data as that is kit specific, but the curved line is the threshold to stay below to avoid risking the rods bending and breaking.

That's really awesome information, thank you. I need to ask though, how do we translate that into something a mere mortal can measure?

I mixed up the buckle limit and the max torque/hp limit, and I referred to the limit as 105psi when the units are in bar, but still, the chart seems to say the limit is 95 bar at 2000 rpms. 95 bar x 14 psi/bar which is like 1400 psi. I don’t know how to convert that to torque.

Torque and psi can’t be converted.

Something like this [Clicky]
Each cylinder will run differently (as shown in the graph), using per cylinder timing and fuelling compensations will be key to keeping them below the buckle threshold if the kit is capable of producing more cylinder pressure. This is also why a torque limit is variable by RPM but theoretically you could make similar torque both being safe (all cylinders making max safe pressure) or risking damage (1 cylinder above the threshold producing more power, others below max safe power).

Obviously knock causes spikes in pressure and that is why it is so devastating. I'm told that so long as the corrections are below -3-4 deg on our ECU it should be OK.

Unfortunately, none of that gets us to tangible numbers that we can use like 'don't go over 275wtq at 6k and 225wtq at 3k' or something.

Going back to the supercharger....

http://www.eaton.com/us/en-us/catalo...tvs-r1320.html

I always thought it was interesting that the 1320 says it is for 3.0-4.5L engines. Cosworth uses a smaller supercharger of course, but here you said this:

https://www.ft86club.com/forums/show...48&postcount=9

Were you saying its map is larger, covering a larger range of boost, so it is unlikely that someone would be outside of its efficiency range? I'm trying to determine where the supercharger is at its peak according to this compressor map as it relates to psi. It looks like it does hit a peak around 11,000 rpms at 1.6 bar or 23 psi, and it looks like it doesn't really even get moving until 6,000 rpms at 1.3 bar or 18 psi (this is supercharger rotations). I'm not really sure if any of that is correct:

https://www.eaton.com/content/dam/ea...-R1320-map.jpg

Edit: in looking back at this I’m pretty sure I got the scale messed up. 1.6 bar is probably an absolute value, so it is probably saying 0.6 bar or like 9psi of boost is the sweet spot, which is why the kit comes with that sized pulley, or maybe outlet pressure doesn’t equal gauge pressure. I don’t know. The Eaton TVS 900 compressor map is below. Similar boost profiles. Higher flow on the 1320’s side, so it will obviously outflow the 900. I suppose someone would have to calculate desired horsepower and calculate the airflow necessary to meet that power then look at the map to find out where the boost will be at that flow rate.

https://www.eaton.com/content/dam/ea...s-R900-map.jpg