mgrotel

iTrader: (3)

omg! well thats what i get for assuming. wow, that thing lost a ton!

kacz07

iTrader: (15)

Ok, I stirred the pot, so let me expand.

1. The headers DEFINITELY improved power, despite the claims that the Cosworth and Injen would cause it to lose power. They prob would have made more power with the Mrev2/spacer combo, if I hadn't switched it out to the Cosworth.

If you remember, my original tune was with the Cosworth manifold, RT Tuning 3" MAF tube, and Megan long tubes. That pull was in 5th gear and you can see it drop off.

Original setup (SAE CF)


Injen/Cosworth/SG (Uncorrected CF)
This higher 2 lines were in 4th/5th gear, peak respective. The low was one of my old Mrev2/spacer runs. Almost 50whp at redline of 7800rpm!


Conclusion: SG headers made ~15whp (286 vs. 302 SAE corrected) on the Cosworth/Megan LTH setup. I wonder what would happen if I ported the Mrev2 and increased the spacer.


2. MAF housing DRASTICALLY affects driveability. I went from a 3" RT Tuning MAF setup--> Z1 MAF housing (which is more like 82mm)--> 3" GTM MAF housing--> Injen CAI (with MAF housing built in, likely OEM).

The Z1 drove the worst, with hot starts being a problem, as well as increased rpms when shifting. Nothing against the product, but it is not particularly great for NA application, at least in my case.

The problem was the revs would jump once I pressed the clutch down to shift. It improved slightly with the GTM MAF and has been ELIMINATED with the Injen/stock MAF housing. One of the reasons why I went with the Injen was to return the driveability back to stock. I didn't like the ghost blips.

3. Again, 1cockyz has stated that the stock MAF doesn't like a housing larger than 76mm. If you're interested in a custom intake with an ideal housing size, he recommends vmptuning.com.

Conclusions:

1. SG headers make power (286whp vs. 302whp SAE corrected w/ Cosworth setup) over Megan's with no tq losses. See dyno comparison.
2. Cosworth DOES make high rpm power. My graph mimics 1cockyz's posted above in the MD/Cosworth debate, but extends til redline.
3. MAF housing affects driveability
4. 1cockyz knows his crap.
5. Need to port Mrev2 and get a bigger spacer. If the headers improve the Cosworth by that much, surely, there is more power in the Mrev2/spacer combo.

I'm going to drive the crap out of my car in the meantime, but I'll be tinkering in the future.

kacz07

iTrader: (15)

+2. That's what I've been doing!

The car doesn't hesitate like it used to around 2500rpm w/ the big MAFs and Mrev2/spacer combo and pulls just as hard up top. It feels like the car begins to accelerate faster and faster as the revs rise. That was noted after the engine build w cams, not the manifold swap.

While driving speeds higher than 60mph, a downshift to 3rd (revs around 4.5-5k), the car takes off. Below 60mph, it's pretty mundane, although I can easily break the tires loose. Could just be my driving habits.

Voboy

iTrader: (58)

^- makes me wonder what happens if you tried a revup lower collector + your cams + 8K redline and then throw a spacer in the mix just to see what happens. good info here... that's crazy how there's a 50hp loss on the mrev2 compared to cosworth at the higher redline. is there a dyno around for the revup lower collector reving out to 7600+?

edit: found revup lower collector going to 7800. https://my350z.com/forum/8750067-post215.html
not as much of a gain as the cosworth with your cams though.

did you get retuned for each mod change and dyno?

Zazz93

iTrader: (2)

Nice!

Hey remember the 3 inch MAF requires your tuner to really do his homework. It changes the MAF's flow characteristics and calcs. Very similar to letting in unmetered air if not calculated correctly.

the_coupe

iTrader: (4)

dear lord. just went through all 18 pages. very informative to the least! and very much appreciated. im not goin all out like you did but still doing plenty (nonrev na build)...and all myself to top it off! will def keep my thread updated....

kacz07

iTrader: (15)

Yeah, not sure if I've seen a lot of literature on the driveability of the larger MAFs other than hot start issues.

I know Vince has put a lot of hours into tuning my car to max power, so maybe he or another tuner can comment on the difficulties in getting that MAF tuned.

kacz07

iTrader: (15)

Doing it all yourself is awesome. Wish I could've done the same. I definitely overdid my build. Probably would've gotten the same numbers with cams and springs. Good luck with your build!

mgrotel

iTrader: (3)

id really like to see a dyno with the sg headers and the mrev2/spacer to see what that looks like above 6200rpm. but it appears the headers were what was hurting your top end. congrats. guess ill be getting rid of my megan shorties after all. thank you sir

KA24DE

That manifold is a piece of ****. You can make the excuse that it extends the powerband (like AdamZ1 does) but the truth is you are losing more power than you are gaining. I Would put money down that majority of that gain is from the headers, and only 2-5whp (if even) can be attributed to the manifold itself.

Of course, this is your build, and you'll do whatever you want. Good luck.

jmccarty

That's a bit of a statement. The Cosworth manifold works great on mine and many others. What specifically did you find wrong with it?

0jiggy0

iTrader: (13)

I think he's referring to the fact that the dyno shows it loses power everywhere except way up to.

kacz07

iTrader: (15)

KA, I'm not arguing about lost power with the Cosworth in the lower powerband. Like I said, I put it in there because I like the looks of it. With the new headers it only JUST beats out the Mrev2/spacer combo I had on before and that comes with the power to redline. Had I kept the Mrev2/spacer combo, I'm sure I would've made more power if I had it tuned. Being that that manifold is off, I'd like to make the proper port/polish to make even more power, then do the same for the Cosworth.

The headers will definitely support more power and likely allowed the Cosworth to at least compete with previous Mrev2/spacer numbers. The Megan's are a good piece for the stock redline, but really suffer above 6500rpm.

For both Mrev2/revup and Cosworth manifold, especially the Cosworth, more power is in the hands of the machinist. Internally, it's a more complex piece.

the_coupe

iTrader: (4)

we'll see how my port matched intake manifold/port matched and modified lower plenum and polished/ported tb area of the upper plenum will respond

Z1 Performance

iTrader: (564)

good to see the numbers going in the right direction

I wish I could comment on what was needed tuning wise with the MAF housing. Jermaine from TXS had done all my last series of tunes when I still used a MAF (since I used the UTEC then). Since then, I no longer use a MAF at all as I converted to MAP sensor when I went Haltech/cable throttle body. Might react differently on a revup/non with you being able to alter both cams (UTEC couldn't adjust for cam timing at all obviously).

The Cosworth, as I have said, makes power exactly where they designed it to make power - up top. It's not a low to mid range manifold, it's a top end manifold, which needs rpm to shine, and needs the right cam/header combo to make it worthwhile. I have said many times why I went with it on my car...I needed something, as I no longer had my previous intake manifold/spacer setup available after trying to get the ITB's to work. So, rather than acquire another stock setup/spacer, and pay my machinist to spend the time to port, polish like he had done my original setup, I tried something new (Cosworth), and was happy with the net changes so it's stayed. Yes, I gave up low end power for top end, and I am ok with that. To some extent that was "fixed" with my 4.3 final drive change from the 3.9. Mine is still not nearly as snappy down low/mid range as it once was, but it pulls much better up top than my original setup, and that was a trade I was willing to live with. Others might not be ok with that. It trades low to mid rpm grunt for top end, no question about it, which makes it not for everyone by any means, but for the right setup, if you want sustained, top end power, it works without question. It all just depends where you want your engine to make it's power, and what the rest of the setup is built around. I'd love to try the SG long tubes on mine to see the net changes as well but my next changes will be focused around trying to introduce some sort of idle control motor into the setup, as I dont have one currently

enjoy the car, glad to see the #'s

mgrotel

iTrader: (3)

i have something very similar. what size spacer and what headers are you going with?

kacz07

iTrader: (15)

With supporting mods, I think there's at least 10whp to be gained from increasing the volume of the plenum and smoothing out the surface. You guys both have the right idea.

http://xbcustoms.com/Rob/intakedyno.htm

Among others, take a look at the custom plenum porting results from Sexyrob's intake dyno test. 3, 5, and 6 are telling of the gains in peak power and the shift in peak.

the_coupe

iTrader: (4)

AFE stage2 intake, MD 5/16 iso-thermal plenum spacer kit along with MR long tubes and ypipe to my custom single 3" apexi exhaust. heads should be done this weekend as far as the porting. then gotta port the intake mani and lower plenum.

i like the cosworth manifold, dont like how big of a loss the lower half of the powerband gets....although....previously mentioned numerous time.....it gives gains in top end....way top. i want power all throughout the powerband, but mainly bottom/mid range areas.

*Boose*

iTrader: (3)

Ugh, just go back to the stock manifold.

KA24DE

I agree. Even the stock Revup manifold is better than that.
https://my350z.com/forum/na-builds/4...argarge-4.html