1st and goal

iTrader: (6)

Last week I went to the dyno and tweaked the tune slightly to accomodate for the "Hedders" as Hedman spells them.

I went with 1 3/4 long tubes, they are made by Hedman and sold through BRP Hot rods.

The motor is from a 98 Z/28 and has an LS6 intake manifold and comp cams camshaft, springs and pushrods. Otherwise the motor is stock. Tranny is a 4L60E w/ Vigilante t/c.

I did three baseline dyno pulls with exhaust manifolds and the first one was 322 @ 5850, the next pull was 312 and after letting the car cool I backed it up with another 322 RWHP pull.

On to the "Hedder" dyno pulls

On the first pull we only spun it up to 5700 and it made 338, we tweaked the tune a bit and it ran it up to 6200ish and it made 355.9 RWHP @ 6150 and torque went up from 273.8 to 304 @ the same 6150 rpm. Peak torque was 327 @ 5200, the previous peak torque was 303 @ 5200

I backed up the 355RWHP run with another 355 RWHP pull and spun it up to 6500. HP remained at 355, it flatlined from 6150-6500 @ 355.





Of course with new found power a trip to my local track (New England Dragway) was required so off I went last night to make a couple of passes

My previous best was 12.730 @ 106.39, other pases that day was 12.781 @ 106.14, 12.794 @ 105.92 and 12.757 @ 105.55. Sixty foot times ranged from 1.821 - 1.848 on the above passes.

With the increase in power my sixty foot times improved to 1.782 1.792 and 1.755.

First pass I cut a .080 light and my sixty foot was 1.782, 7.842 @ 88.03 in the eight and then I bounced off the rev limiter a couple of times and as I ran thought the lights I looked up and saw 12.330 (well actually I only saw the 33) but you get the gist... so it was a 12.330 @ 109.60, next pass I red light by a c/h (.004) and sixty footed to a 1.792 and ran 12.384 @ 109.26 with again bouncing off the rev limited on the 2-3 shift. I decided to give it one more shot before I left and cut a 1.755 sixty foot (.102 light) and ran 7.790 @ 88.62 and again as I go through the lights I crouch down and lookup and saw a "25" , drive around and get my slip and it's a 12.256 @ 109.96 with again bouncing off the rev limiter twice before it shifted into third. My buddy has the laptop with EFI live so at the time I was stuck and couldnt' make any changes.

Bottom line I picked 34 RWHP, 30 RWTQ on the dyno and a solid 3+ mph and almost a half second at the track.

These "Hedders" are by far one of the best investments I made as far as dollar vs. performance gain.

Marc

dman

iTrader: (5)

sweet, nice gains. got pics of the car? don't see too many 73 Z's anymore

ryanvv355

iTrader: (17)

Good numbers man, congrats!

1st and goal

iTrader: (6)

http://s258.photobucket.com/albums/h...urrent=027.flv

Thanks guys, above is a link to a burn that will make you proud and below are some pics

cacmanjr

iTrader: (14)

Great looking car there. Runs well too. What are the cam and converter specs?

ryanvv355

iTrader: (17)

Where you running those times on a street tire?

1st and goal

iTrader: (6)

The cam is a Comp Cams cam Part # 54-428-11
Specs are:
Dur @ 050 228/230
Duration 281 / 283
Lift 571 / 573

The converter is a Vigilante and is around 2400 stall, I'll probably take it out over the winter and send it back to loosen it up a c/h.

Tires are Mickey Thompson 255/50/16s
Those are my full time tires....too lazy to change them

Oh, one more thing....this was a numbers matching car before I got ahold of it, but if you look at my main page, you can see from my "redneck / de-redneckification" pics that I have improved the car in overall appearance and driveability from when I first got it three years ago. My original old school small block ran a best off 13.8 @ 98 mph

http://www.cardomain.com/ride/2532279

cacmanjr

iTrader: (14)

Thanks for the information. I though that the set up would be more radical than that. I am glad to see that it is not.

69 Ghost

Can you comment on the fit of the headers? I did not go with them but decided on Stainless Works instead and they have been on backorder for 3 weeks already.

1st and goal

iTrader: (6)

I was very impressed with the headers, they fit in great. The drivers side went right in with no issues. I removed the plugs and bam it bolted right up. For the pass side I had to remove the starter (and of course the plugs) and it also slid right in. Due to the A/C box that I still have that side was a bit more of a pain in the *** due to tight clearance to get at some of the bolts / rear spark plug (Tip of the day, when I had the headers just laying in there loose, I installed the spark plug and then lifted the headers and bolted it up).

Here are some more pics.

I would definatly reccomend these "Hedders"

















I've got more in my photobucket album at:

http://s258.photobucket.com/albums/hh250/marc73z/

1st and goal

iTrader: (6)

One more

alocker

iTrader: (10)

Those hedders look great but my concern is the slip fit collectors. Do they leak at all??

Nice times for a mild LS.

1st and goal

iTrader: (6)

Thanks..... Nope

1st and goal

iTrader: (6)

I was able to scan my timeslips

Stu Cool

iTrader: (13)

Very impressive! What gear ratio are you running? Also how are the street manners for that cam? What about the rest of your exhaust, were you running with headers open or closed?

Pat

1st and goal

iTrader: (6)

Uncle Pat, Thanks

Rear end gears are a mystery, I'm guessing 3.42 as it cruises at 2200-2300 @ 72 mph. I was told 4:10 when I bought the car three years ago and I've never taken the cover off to check (on my to do list).

Street manners are good, good midrange and overall power.

I was running through the exhaust 1 3/4 long tubes w/ 3" collector then merged to a 2½ exhaust w/ Flowmaster mufflers.

Marc

Awesomeperfmachine

Nice Car!
I assume you used the BRP motor mounts? If not may I ask what you did use?
Also, how much for a set of these?

1st and goal

iTrader: (6)

Hello, yes I used BRP motor mounts.

I got in on the pre-order price - $599

1st and goal

iTrader: (6)

I got a couple more passes in at the track last night.

First pass - had a crappy launch 1.86 sixty foot and ended up 12.561 @ 108.91.

Got back in the lanes and did a mean burn and launched harder and cut a 1.799 sixty foot and cut a 12.311 @ 110.42

Good pass and physched that I had a solid 110 mph run

Last pass before I packed it in was a 12.266 @ 110.37

During my track sessions I spanked two Mustangs and an import.

So close to a new best ET but yet so far away.

All in all a good night, not sure if there's much left in the ways of improvement. Hoping to get up on a Saturday or Sunday test and tune and hope that a better prepped track will allow me to come out of the hole a little harder.

The track closes at the end of October so I've only got a little bit of time left but I'll keep giving it hell and keep you guys posted on my progress

So as far as improvements go from the "Hedders" I'm still at almost a half second improvement but now I'm to a solid 4 mph improvement with the headers (previous best mph was 106.39 and new best last night was 110.42)

Thanks to BRP and Hedman for making a great set of "Hedders"

fast

iTrader: (24)

early 2nd gens are sweet
sharp car ya got