darren_dallas

I was hoping someone could help me with two questions:

1. I had HRE 540R wheels installed today (or tried to at least) and found out the standard lug bolts for the AMG wheels were too short for the new HRE wheels. Does anyone know how long of a lug bolt I need to buy and where I might purchase them? From the Mercedes dealer? O'Reilly?

2. I had my car dyno'd today since I'm having mods installed tomorrow. My best pull was 391 hp and 432 torque at 107 degrees in the bay (and pretty darn humid in Dallas today). Would the heat be killing my hp this much? 391 is about 20-23 lower than the averages I've heard on here. I hope someone confirms that the heat and humidity would lower it by 20 hp or so.

Thanks in advance for your help.

medici78

I'm looking at your sig. Osborn racing? Never heard of them. FIll us in.
Anyway, did you have a fan on and the hood open during the dyno run?

darren_dallas

The hood was open, but no fan. I asked them about a fan and they gave me some fluff response that didn't make sense.

Osborn Racing is a small custom outfit I had make some headers and pulley for me. They said they've done some stuff for other local MB'ers so we'll see. They install both for me tomorrow when my wife and I drive up to Arkansas. The price was great which is why I went for them, but I don't want to tell you they're the BOMB yet since I haven't got the installed. Aske me next week and I'll let you know. The price was incredible though for both parts installed...$3k

houston

We'll find out soon enough.... Sometimes it's worth the EXTRA few to get something you know that is reputable and confirmed by many others... but there's nothing wrong with saving!!! best of luck!

Gregs210

Hi, the other half of your question is a little more complicated, if that's possible.

While all MBs other than the G use a 5x112 lug pattern, since they use bolts instead of studs/nuts you often run into this situation. (The other problem is that some cars use 12M lug bolts and some use 14M, and the ball seats aren't the same; that's an FYI for anyone else reading this thread.) At any rate, unless you are lucky enough to come across someone with this EXACT combo, no one's really going to be able to tell you which bolts to buy, but here's how you can figure it out yourself.

Take one of your stock wheels off the car and then drop one of your lug bolts in a lug hole. Stuff a paper towel down in on top of it so it will hold it, be sure to leave some paper towel out of the hole so you can easily get it out. Now from the inside mounting edge, measure how far the bolt threads extend through the wheel; it will probably be about 3/4 inch or so.

Now do the same with one of your lug bolts and one of the new wheels; if your lug bolts aren't even visible in the HREs, it will be more difficult. Hopefully you'll be able to see them almost protruding and then you just have to figure out the distance from the end of the bolt to the mounting edge of the wheel (the inside edge) and then add that number to the first measurement you took on your stock wheels.

Still with me? There's one more step. Since you now know how much longer your new bolts need to be, you need only measure your bolts and then add the new length. The trick is that it's not the *overall* length of the bolt, but just the length under the ball seat.

Now that you have the measurement, you can find the right ones all over the web. An awesome source is www.prestigewheel.com; they're a little more expensive, but top quality. They have graphic representations that show you the measurements very clearly.

Sadly, your MBZ dealer might have the bolts, but they'd have no idea how to look them up. Every tire shop I tried when I was going through this was similarly unhelpful. It was a nice trial by fire...

Good luck and enjoy the ride,
Greg

darren_dallas

Thanks Greg that does help. I know lug bolts are 14mm and I just need about another .25" worth of thread when using a ball seat type of bolt. A cone seat should work just fine I believe.

darren_dallas

You're right Houston. In this case I had the wife bringing the hammer down so I had to get creative.

medici78

$3k, assuming they're made well, is a steal. Let us knnow, I'm sure a lot of folks here would love to have the same deal!
As for no fan, that might be a factor, as its not dissipating the heat the way most people dyno. However, leaving the hood open might have helped a little.

Rafal

German company H & R makes racing suspension kits, springs and Track Spacers.
Every spacer, 5, 10, 15 or 20mm will requires a longer than stock bolt to give you a minimum 6.5 turns of the thread. A little too long does not matter, you have a through and through thread in the hub! I use spacers and longer bolts on all my cars to widen the track, especially on the rear axle.
Contact H & R , www.hrsprings.com, who will give you their local agent in you area to supply you with the exact length and head shape bolt you need.

lee2375

All HRE wheels come with new lug bolts. I'd call the place you bought them.

DerekFSU

No fan for the dyno? That's nuts. That engine needs air and is expecting 100 mph winds coming into it for cooling purposes when you are going 100mph on the dyno. I think that will definitely hurt your performance but I do not know how much.

darren_dallas

Sounds like I need to have it dyno'd somewhere else where they use fan. Thanks for all the input.

Schiznick

I would question anyone who does not use additional cooling when running a car on a dyno.

The other factor is what kind of dyno was it? Hard to compare numbers from different locations, temps, humidity and dyno's.

Good luck

DerekFSU

Dallas, I forgot to mention that I had similar numbers before my mods. Off the spray, I currently have abour 430 rwph and 470 lb/ft.

housclass

the real dyno is the race track! it all boils down to the quickest car, not horsepower...my $.02 cents worth!

example...derek is making the same dyno numbers i am but he's running 11.60's...me 12.0's...every dyno and dyno situation is different.

take it to the motorplex and run it just before the sun goes down.

good luck with the mods and let us know how it turned out!

darren_dallas

Ok, drove back from Little Rock to Dallas last night with the new mods. Due to Traffic I couldn't really test if off the line and I wanted to drive a while and let the computer get used to the new air flow.

After about 30 minutes of driving I decided to punch it. We were already going 80 and when I floored the gas both of our heads (my wife and mine) got slammed on the headrest and my body was planted on the seat. The force felt similar to punching it at 30 mph before the mods. My wife looked at me with a big grin and said 'Oh yeah'.

I'll try some off the line starts and rolling from 30mph stuff later this week when I get back from my business trip in Chicago. I'll also go back to the same place and get it dyno'd again so I have baseline numbers to work from.

Also, the supercharger makes this sweet noise now with the air rushing in and the headers give it a nice growl. Just sounds sweet!

Now, where's my local Saleen owner?!