First take into consideration that my track is at 4000’ elevation. I plan to go a to a sea level track this summer. Well maybe, if I can figure out what is up with my clutch (I’ll explain later).

Well I went to the track a year ago and my best 60’ was a 2.375 but that only happened once. I couldn’t do anything else but a 2.4 or worse. My best time was a 15.387 @ 94.2mph.

That was with:
y-pipe
popcharger intake
UDP
MEVI
custom catback exhaust

Weight reduction:
passenger seat
rear seat
spare tire
jack
floor mats
1/4 tank gas
stock wheels in front


This year I went to the track again with the exact same setup however with the MEVI extrude honed and I forgot to take the spare tire and jack out, and unfortunately my clutch slips everytime I shift quickly. It’s really bad from 1st to 2nd, and then not as bad from 2nd to 3rd. So what I am ending up having to do shift slower so the clutch won’t slip. What I mean by slipping is when I shift the RPM’s go down slowly until the clutch catches instead of just dropping to the RPM’s and catching like it normally would. So this has slowed me down which sucks because I think the outcome would be better. Anyhow this year I yielded a 60’ of 2.289 as my best with a 15.33 @ 93.4mph and now I’m consistently getting 2.3 60’s. Now I know what you’re thinking that I only got .05 faster. Again you have to remember that I have to shift differently because of my slipping clutch which is wasting time. I am convinced that if I could shift normally that my best run this year would have been a 15.2 or better and that I would be running 15.3’s consistently. I’m just really irritated because I just got a new clutch a year ago. I’m going to be really upset if this one is already going bad.

The slip reads as follows if I can remember correctly, I’ll update this when I know for sure. I don’t have it with me but I believe it was:

60' 2.289
330' 6.49
1/8 9.94
mph 72.32
1000' 12.87
1/4 15.337
mph 93.42

All in all I am happy I got it. It feels better down low and great up top. Now just to work on getting the JWT ECU upgrade.

 

Dynos? I hate elevation I'm at 5400'.

http://www.nhra.com/tech_specs/altitude.html

 

wow 15.3? that sounds pretty high, i didnt know elevation matterd that much

 

Unfortunately there is no DYNO shops around my area. When I go to the lower sea level track this summer I'm going to see if I can find a dyno shop there and make an appointment before heading over to the track.

 

So your running the MEVI with out the upgraded ECU?

 

how much did it cost you to get it extrude honed?

 

Before/after dyno plots would have been tons more helpful.

Did you really lose a little on trap speed too? I know your clutch is slipping somewhat...get that fixed!
lol

 

You have no idea how badly I would like to get a dyno but the closest one is anywhere from 2-3 hours away. So it's not the most convenient thing. When I do make the trip we'll be able to at least somewhat get an idea and compare to others. While that won't be entirely accurate it wll give us an idea.

Yes I have the MEVI without the ECU. But hopefully for only a few more months.

As for my trap speed that 94 I got was the only time I had done that. Everything must have been just right on that run. Most of the traps that day were 92. This time most were 93.

Extrude Honing isn't cheap but I didn't mind. It was $600. I wanted to see what I would yield. Besides it's nice to be different every now and then. Although the 00VI would be cheaper I still like my MEVI. And it will give a little more research for those that are inquiring.

 

One thing, maybe you had time constraints or conflicting schedules, but seems like money isn't an issue, just curious, wouldn't $600 be better spent partially on a dyno? My dyno is about 1.5 hours away, and i find the time to go between mods. ..

 

I would love to see a before and after dyno...but you already extrude honed it...

was there an immediate difference in the "butt dyno" though...or did the improvements just show up in your track times...??

 

do you have the dates and times of both of your best runs with mevi and with EH mevi ? i would like to do some research with the info, just post here, usually the info is on the timeslip

 

I believe the MEVI run was March, 13th 2004 at about 2:00 in the afternoon. The EH'd MEVI run was April 9th 2005 at about 12:00 noon.

To me it felt a lot better down low and up top. Obviously it's not a dramatic increase because it's probably only around 7-10 hp and tq but it does feel well from 5500 to redline and really well between 5500-6000.

 

IMO, in this situation not much can be told from your track results and a dyno comparison is not possible so I guess we will never know.

 

that might be right, i was thinking that if the 60 foots matched up i might could track down the weather to take a look at relative hp. hacim105 what town is this track in, one thing i forgot to ask.

mike are you sure those numbers are right for your max ? lol just kidding the turbo is looking great .. 260 hp must be nice !!

 

where can someone get there manifold extrude honed

 

laylow1988, I'd wait to see actual gains before I went and did it.

 

It was in fallon, NV.

Well I hope to get my clutch fixed if that is truly the problem. I found out the other day that my slave cylinder had a rip in the boot. So I'm thinking it had something to do with that because everything was fine but then I swapped in a SS clutch line and everything seemed to be fine even with my USIM. It slipped a few times. Then I swapped in my EH'd MEVI and it will slip everytime when trying to shift quickly, up at redline that is. I know that's beating on my engine but I've been trying to see if anything has changed. So I get my new slave cylinder tomorrow and I'll probably on Thursday so hopefully there will be soe good results. Otherwise I'm going to be pissed.

Sorry that the comparisons aren't very good. I was mostly happy and wanted to tell everyone that I got my MEVI extrude honed. When I get more conclusive info and evidence I'll post more info. I believe my friend might be getting a MEVI so if he does I'll ask if I can borrow it for dyno purposes.

 

sounds good if you can remember send me a pm when you get new results

 

interesting info

 

oh elevation matters for him probably a lil less than a second the track i race at around 5000ft above sea level and na cars see losses of a second or more

 

Check out my 2nd post in this thread

the correction factors for his track are there ...

 

Get that clutch fixed and go back to the track.

IMO, it's a waste to run at the track when your car isn't in the same shape it was in when you last tested it.

 

Fallon, NV - MEVI RUN - March, 13th 2004
TEMP: 68F
BP: 30.3
HUMIDITY: 17%
ALT: 3963
Calculated Relative Horsepower: 88.5%
Calculated Dynamometer Correction Factor: 1.131
------------------------------------------------
Fallon, NV - " EXTRUDE HONE" MEVI RUN - April 9th 2005

TEMP: 48F
BP: 29.91
HUMIDITY: 41%
ALT: 3963
Calculated Relative Horsepower: 89.0%
Calculated Dynamometer Correction Factor: 1.124

about the relative HP calculator:

Air density is affected by the temperature and humidity of the air. On a hot day, or at high altitude, or on a moist day, the air is less dense. A reduction in air density reduces the amount of oxygen available for combustion and therefore reduces the engine horsepower and torque. This calculator shows you how much the air conditions on any given day will alter the horsepower of a normally aspirated internal combustion engine. For example, at 85 degrees F, 30.14 Inches Hg (mercury) barometer reading, 40% relative humidity and 5000 feet altitude, the engine only produces about 81.1% of the rated horsepower. info from relative hp website

 

About a 0.5% difference as far as conditions, just need to get the clutch fixed.

 

How did you work around the butterfly valves and makeing the inside diameter larger???

 

They have some way of blocking off that area so it doesn't get extrude honed. I talked to one of the engineers (I think) and he said that I could get the butterfly area open also but it wouldn't help much plus I'd have to modify the rod that sits holds the butterflies and then find bigger butterflies to better enclose the opening. They will even open up your throttle body area if you want them to. And I don't believe any of that costs extra. Not that this will inspire you to get it down but that might be something that those who will get their MEVI or USIM extrude honed might be happy about.

 

get things fixed up on that max , im eager to see how well you do your next time out. hey you mentioned 600, they told me 650 i wonder if they have went down in price since they gave me the quote, i have the usim.

do you recommend replacing any other parts on the car when doing the swap ?

 

It is a shame you couldn't do a before and after dyno. I think that EHing the MEVI would help with the low end loss and give some more top end.

 

I'm sorry I checked my CC statement and it was $650.

h2ksPig: I know I don't have a dyno but it does feel like I have the power back that was lost and extra on top. Obviously it's just a butt dyno and I could be tricking myself because I want it to feel that way but I was driving around with my USIM for 3 weeks and from one to the other it doesn't feel like it did before where it lost power down low. It feels like the USIM down lower, perhaps even a little better. I'm going to try and fix my clutch problem and get back to the track. However, there isn't another test n tune at the track until may. So we'll see how things go.