Dyno results are IN!!! not that impressive by hybridZ standa

[Guest bastaad525]

FINALLY got a chance to take the new setup down to the dyno... and got some kinda interesting results. Well first I'll list the results from the last dyno pull I did, though it's kinda useless for comparison I guess because it was done at a different shop, but I'm looking more at where the peaks are occuring not the actual numbers anyways.

 

First run:

140.5 RWHP @ 5300RPM

151.4 ftlbs tq @ 4300RPM

 

Last run (out of 4 total):

146.9 RWHP @ 5400RPM

161.4 ftlbs tq @ 4300RPM

 

This was from my '80 280ZX, with rebuilt engine, bored out .060 over (giving rougly 2.9L) stock N42 except for stainless polished valves, stock cam, K&N intake, big bore TB, 3-2-1 headers, free flow can and muffler, regular bend piping, MSD ignition and coil, stock efi with addition of adjustable FPR

 

It's interesting to note that the torque curve varied about 14 ftlbs from 2500RPM to the 4300RPM peak, and fell off rapidly after 4500rpm, down to 138ft lbs at 5500.

 

Okay now todays tests. This is with the same engine, but in a '72 240Z, running a mild cam (480 lift 270 duration on STOCK springs by the way...) and rebuilt Ztherapy SU's with SM needles. Only other difference is the exhaust, as on the 240 I didn't need to run a cat. Same muffler, but I also added a glasspack to lower the noise level a bit.

 

First run:

158.6 RWHP @ 5750RPM

153.1 ftlbs tq @ 4750RPM (both peaks up about 400rpms)

 

This was with the carbs set to run as close to stoichometric mixture as possible throughout a large part of the rev range (previously tuned on a smog shops exhaust gas machine). Actually scratch that, I had set it 1/4 turn richer from that setting already, between the time I tuned them at the smog place and the time I went to the dyno. I richened it up another 1/4 for the second run and got:

 

161.6 RWHP @ 5500RPM (down 250)

158.3 ftlbs tq @ 5000RPM (UP 250...??)

 

Richened it up another 1/4 (3/4 total from stoich) and got:

 

159.6 RWHP @ 5500RPM

159.8 ftlbs tq @ 5000RPM

 

Hmmm which is better??? Slightly lower torque and slightly higher hp?? or the other way around.

 

The great thing is the torque curve... much more flat and even then it was at the other shop, only varying about 7 ft lbs from 2100 to about 5400RPM... that's a pretty wide usable band! The WEIRD thing is... since when do L28's peak torque and HP numbers darn near match??? Every L6 I know of that's been dynoed has always had a higher torque than HP number. Anyways... I only got enough time to mess with the mixture between runs, in a couple weeks I'll go back and fiddle with the timing and hopefully get a couple more HP out of it. Oh by the way the place I got todays results from is up in the desert, approx 2000 ft above sea level... the shop guy said it would probably equal about 4% loss.

[David K]

hey those are sweet numbers for RW power! hey next time you go dyno, shoot me an email.

[Drax240z]

Hey those are pretty good numbers! A significant improvement over stock for sure, and not a huge list of modifications. I bet the biggest performance mod you did was moving that engine from the zx to the z though! Nothing like shedding a few hundred pounds to gain everywhere...

[David K]

Originally posted by Drax240z:

I bet the biggest performance mod you did was moving that engine from the zx to the z though!

[Guest bastaad525]

Sure David I'll keep you in mind... hopefully gonna go back in a couple of weeks and tinker with the timing. The shop I went to is out in Lancaster though so it is a bit of a drive from you.... heck it's quite a bit of a drive from me!! The guy is really cool though and his prices are great. It pretty much boils down to either $20 a pull or $100 an hour depending on what you're doing, and unlike most shops I know this guy has NO problem letting you tinker with the car yourself between pulls.

[Guest bastaad525]

So any of you guru's can advise me as to which is the better setting?

 

161.6 HP @ 5500

158.3 TQ @ 5000

 

or

 

159.6 HP @ 5500

159.8 TQ @ 5000

 

The HP and torque peaks also fall off a bit faster with the second setting, differing by about 4 or 5 hp and ft lbs by the 6500RPM redline.

I know it's kinda splitting hairs but when every tenth counts... hairs add up

 

Also keep in mind that the third setting is a little richer, but that was tuned at 2000ft, so I'm assuming it would actually fall back closer to the second setting when I got back home (not sure of the elevation but pretty close to sea lvl)?

[Drax240z]

I'd run with whichever gives you the largest area under your torque curve. Also take a look at what is happening lower in the rev range... unless its a pure track car, you'll be spending some time around 3k too...

[Guest bastaad525]

hmmm well yeah the third setting with 159 and 159 gives a little bit broader of a torque curve too. As far as at lower RPM well they only tested it from 2200 to 6k-6.5k, and between 2-3k it is nearly identical between the two settings. I thought of that too because i do drive in the city 90% of the time so I dont want a slug at low rpms. It actually did get a little more sluggish off the line ... darn SM needles run way too rich at idle, so anyways I bumped the timing up about 4 degrees and am listening very intently for any ping... I have a feeling I'm still right on the edge for that. The 4 degrees did help it off the line some though, so hopefully I can keep it that way.

[Mike C]

Nice combo. My guess is the numbers you are talking about are within the error range of the dyno. Basically too close to call.