Thinking About Going Sc Ess Or Harrop?

[pbonsalb]

Originally Posted by FogCityM3

One thing that I've been contemplating in addressing one of the "weaknesses" of the S65 on the track is that to keep up with the mid and rear engined cars, it could use more torque coming out of corners, particularly some 3rd gear corners where downshifting into 2nd is impractical but the engine could use a little more "oomph". Strokers and a shorter geared diff are two options but can perhaps see where a Harrop-type design might present some advantages. The combination of a front-engine rear-drive setup to "dive bomb" in the corners while having more torque coming out (provided you have right grip) and similar predictable feel on the top end would probably be unbeatable.

The torque tradeoff is only on the low end. If you are writing that there are some 3000-4000 rpm corners, then you are right. I am sure there are no 2000 rpm corners. But the Harrop can't hang with the ESS650 on the top end.

Its a compromise. The Harrop is the better lazy shifter daily driver supercharger. The ESS650 is better for the active driver.

I think Regular Guy did a dyno plot of an ESS625 against the Harrop. I think he even calculated the power under the curve to see which made more overall.

[pbonsalb]

Originally Posted by steven_s

Any news regarding stage 2/3? Would love to see what that brings to the table.

Also whats with everyone running ~8psi. I figured with higher compression there'd be more in the 10-12psi range?

12:1 CR port injection on pump gas is not boost friendly. Have to keep the boost low. Centrifugal is limited by design in the midrange which helps reduce likelihood of knock, and it is by design higher at peak rpm, where knock is not as much an issue due to lower cylinder pressures. So the centrifugal can have a higher peak boost than the positive displacement blower. Neither will be 10-12 psi safely on these motors, however. 10 psi would be the upper end and I am not sure any kit maker wants to warranty stock motors at that boost.

At some point, the factory rods are maxed out, but I do not think that is why the kit makers run low boost.

[81bear]

OP - This may help with your decision... Specifically post #1089

http://www.m3post.com/forums/showthr...ess625&page=50

[FogCityM3]

Yes, this would be more in the 3,000-5,000 rpm shifts in 3rd gear specifically, where downshifting can lose time or can result in reduced smoothness particularly in off camber turns with late apexes. In theory one should be able to downshift, but it depends on the track and whether being smoother is faster (usually the case). A few members, one of whom tracks avidly, had his standard ESS/Evolve type supercharger (can't remember brand) removed and kept it N/A because that power on the very top wasn't useful on the track and sure enough his laps times went down immediately. The top end power, heat soak, and extra weight provided no benefit at the track.

Of course if you want to run airstrips and drag races, overall power wins, but as for myself looking at what will work best on a track, where I personally have far more fun, that extra torque on the low end, high control at the limit, and ability to dive bomb corners I think would result in a potent track weapon.


QUOTE=pbonsalb;18251383]The torque tradeoff is only on the low end. If you are writing that there are some 3000-4000 rpm corners, then you are right. I am sure there are no 2000 rpm corners. But the Harrop can't hang with the ESS650 on the top end.

Its a compromise. The Harrop is the better lazy shifter daily driver supercharger. The ESS650 is better for the active driver.

I think Regular Guy did a dyno plot of an ESS625 against the Harrop. I think he even calculated the power under the curve to see which made more overall.[/QUOTE]

[Longboarder]

The powerband of the ESS 600+ kit is a mirror that of a Ferrari 458 Italia. Accordingly, I get very little wheel spin and therefore I get to use all the power. First gear starts spinning around 5,000 rpm and second gear starts to spin around 7,500 and third gear starts spinning around 8,400 (my rev limit is 8,600). I just have to be smart about which gear I am in. It's a much more rewarding experience to me than a turbo car. As I have said many times on this forum, I prefer the power delivery characteristics of my ESS 650 M3 then my 911 Turbo S which makes 750-800 HP. And if I could only choose one, it would be the ESS M3.

Reliability over 30,000 miles has been, well, perfect.

[Sered]

Originally Posted by Longboarder

The powerband of the ESS 600+ kit is a mirror that of a Ferrari 458 Italia. Accordingly, I get very little wheel spin and therefore I get to use all the power. First gear starts spinning around 5,000 rpm and second gear starts to spin around 7,500 and third gear starts spinning around 8,400 (my rev limit is 8,600). I just have to be smart about which gear I am in. It's a much more rewarding experience to me than a turbo car. As I have said many times on this forum, I prefer the power delivery characteristics of my ESS 650 M3 then my 911 Turbo S which makes 750-800 HP. And if I could only choose one, it would be the ESS M3.

Reliability over 30,000 miles has been, well, perfect.

You need some better tires if you're spinning in second You need to try these puppies out. As for first, I can scarcely build any boost in 1st it ends so quickly. Also possible I'm getting belt slip because the motor is wanting to spin up so fast.

But I'm in agreement with LB. The powerband with the centri kits is just enhanced all around; after 3k rpm it's essentially adding 100-150ft-lbs of extra torque flat all the way to redline. Has a powerband similar to a motorcycle.

[Longboarder]

Originally Posted by Sered

You need some better tires if you're spinning in second You need to try these puppies out. As for first, I can scarcely build any boost in 1st it ends so quickly. Also possible I'm getting belt slip because the motor is wanting to spin up so fast.

Tires are important I agree. But I'm keeping the stock comp package wheels (2 sets) for the sleeper look so I'm limited with the tires I can run. I have 275 PSS for my daily tires and 275 NT05's for my track tires.

Both of these tires are terrific. I've tried a few. I think I will be able to get closer to redline in 1st and remove wheel spin in 2nd and 3rd entirely once I get the soild subframe bushings installed. There's just so much deflection it's difficult for the car to effectively transfer power particularly at over 600 HP.

[whats77inaname]

Originally Posted by BobS

Go with a kit that has local support and good local support. Trust me.

What shop in the North East / NY area knows the Harrop? Who is authorized to install it, has the software, and can trouble shoot if you have a issue? I know there are plenty of shops very familiar with the ESS kit. As already mentioned, you will be able to buy a 625-650 kit for less than the base harrop that has less power. Ess has the ability to set readiness and pass emissions, does harrop? If yes, has anyone actually passed with it? As the M3 ages, your going to have to pass state inspection.

You need to ask all these questions when you add 200HP to your stock m3. Ess is easily upgraded, it has a good name so resale wouldn't be hard if you part out down the road and its reliable. I'm extremely pleased with my ESS kit, good luck with your decision.

You had the Evolve kit at one point. What happened that moved you over to ESS?

[rocket_science]

Originally Posted by Sered

You need some better tires if you're spinning in second You need to try these puppies out. As for first, I can scarcely build any boost in 1st it ends so quickly. Also possible I'm getting belt slip because the motor is wanting to spin up so fast.

But I'm in agreement with LB. The powerband with the centri kits is just enhanced all around; after 3k rpm it's essentially adding 100-150ft-lbs of extra torque flat all the way to redline. Has a powerband similar to a motorcycle.

Ok, so.... Are you serious about the 315's? If so, how are you fitting these??
What wheels/offset, body modification, suspension?

I am running 295/35/18 and these barely tuck on my 10.5 TE37 SLs (et20).

I would kill to fit 315s!

[Lone Star M3]

Originally Posted by rocket_science

Ok, so.... Are you serious about the 315's? If so, how are you fitting these??
What wheels/offset, body modification, suspension?

I am running 295/35/18 and these barely tuck on my 10.5 TE37 SLs (et20).

I would kill to fit 315s!

You can fit 315's no problem with a minimum of a et33 offset. Some tires run wider than others so take that into consideration.

[rocket_science]

Originally Posted by essdb1

You can fit 315's no problem with a minimum of a et33 offset. Some tires run wider than others so take that into consideration.

So when you say minimum of et33, you mean in the direction of et34, not et32 right?

[Lone Star M3]

Originally Posted by rocket_science

So when you say minimum of et33, you mean in the direction of et34, not et32 right?

Yes Sir!

[Joe S]

I have the Harrop kit and couldn't be happier , the sound is awesome and turns lots of heads! The fitment is immaculate and looks OEM! I was stopped by police once and even they were impressed!

[Sered]

Originally Posted by rocket_science

Ok, so.... Are you serious about the 315's? If so, how are you fitting these??
What wheels/offset, body modification, suspension?

I am running 295/35/18 and these barely tuck on my 10.5 TE37 SLs (et20).

I would kill to fit 315s!

When I fit my 295 PSS tires on my VMRs (19x11+25), there was a mild bit of rubbing on the inner wheel well against the liner on the frame. On the TE37SLs I went up to a 18x11+34 so that I could run a wider tire. The rubbing on the inner wheel well was more severe, so I had it trimmed in a crescent shape around where it was rubbing. This gave me the clearance I needed to prevent any rubbing. The trim sits off the frame a few mm and the trim is a few mm thick itself; trimming that gave it plenty of room.

On the +34 offset, there is pretty much no more room to go inward. The tire is ALMOST touching the shock, I can't fit much more than a few index cards back there and when fully unloaded the tire touches the subframe 'ear' that connects to the X-brace (there's plenty of clearance when fully loaded though).

I think one could go wider, but not much wider. It'd have to be done with a more aggressive offset and some inner fender work.

FWIW, these 315s are significantly wider than my 295 PSS tires were (more than 20mm I'm sure), so it's possible they run wide. The tires are amazing though, they grip extremely well (a 200TW item on the level of RS3s and AD08Rs) and significantly outperform R888s in bad weather.

[rocket_science]

Originally Posted by Sered

When I fit my 295 PSS tires on my VMRs (19x11+25), there was a mild bit of rubbing on the inner wheel well against the liner on the frame. On the TE37SLs I went up to a 18x11+34 so that I could run a wider tire. The rubbing on the inner wheel well was more severe, so I had it trimmed in a crescent shape around where it was rubbing. This gave me the clearance I needed to prevent any rubbing. The trim sits off the frame a few mm and the trim is a few mm thick itself; trimming that gave it plenty of room.

On the +34 offset, there is pretty much no more room to go inward. The tire is ALMOST touching the shock, I can't fit much more than a few index cards back there and when fully unloaded the tire touches the subframe 'ear' that connects to the X-brace (there's plenty of clearance when fully loaded though).

I think one could go wider, but not much wider. It'd have to be done with a more aggressive offset and some inner fender work.

FWIW, these 315s are significantly wider than my 295 PSS tires were (more than 20mm I'm sure), so it's possible they run wide. The tires are amazing though, they grip extremely well (a 200TW item on the level of RS3s and AD08Rs) and significantly outperform R888s in bad weather.

Thanks for the info!

So doing the math here... I'm on the te37sl 18x10.5 et20... You have the 11 so that equates to .25 (6.35 mm) wider on the inside and outside... But yours are 14mm further in to the car...
So on the outside I am only 7.65mm further out than you (14 - 6.35) and on the inside, you are 20.35mm further in than me (14 + 6.35)!

So out of curiosity, how close are you on the outside edge? Are you a hair away from rubbing the lip? What I'm thinking is why not run like a 5mm space to give yourself some room on the inside?

[Sered]

Originally Posted by rocket_science

Thanks for the info!

So doing the math here... I'm on the te37sl 18x10.5 et20... You have the 11 so that equates to .25 (6.35 mm) wider on the inside and outside... But yours are 14mm further in to the car...
So on the outside I am only 7.65mm further out than you (14 - 6.35) and on the inside, you are 20.35mm further in than me (14 + 6.35)!

So out of curiosity, how close are you on the outside edge? Are you a hair away from rubbing the lip? What I'm thinking is why not run like a 5mm space to give yourself some room on the inside?

I've got a good 5mm of space. I haven't had time to mess with it as I would want to make sure I wasn't rubbing on the fender itself. It would definitely look more sexy for sure