Currently building my 350z to hopefully make decent power on 94 octane. I believe I have all of the essentials ( built cp/carillo, 625+ arp studs, twin 6765 ctr's,, SFR turbo manifolds, big tomei cams, Hellcat pump etc..) The only thing I'm worried about is my cold side piping. My old setup was a greddy kit with some 60-1 tdo6sl2's, which made 600 on 16 psi but the IAT's was the limiting factor once raising boost above that.

My question is, does anyone know what kind of power the greddy 18G twin turbo intercooler is good for? After basically getting rid of all Greddy stuff off the car due to it all just being garbage I'm not too confident in it. Im hoping to hit somewhere around the 750-800whp, I realize its a good amount of power for pump gas and not easy to obtain.

Thanks for the help guys
Cheers,
Tanner

 

I already like where this is going ... I'll take this challenge on!

I think 750hp to 800hp is definately past the limit of pump gas...your ignition timing cant take too much past 22 to 24psi of boost before knocking.

except, I cannot find a gas station that has 94octane! Would you allow me to purchase 94octane fuel from the track?

I agree with your assessment of the greddy kit...my greddy kit is in the rearview mirror...for a reason.

Dare I share some (well-known) secrets that'll get you up into the 700s? hmmmmmmm

any other takers wanna take this challenge on? I know we got some FI builds going on right now!!!! Hey GreyZ!! lets do this!! Anyone in for a $20 buy-in, no holds bar dyno (Rally Group B type) shootout? We establish a few ground rules (dyno correction, fuel grade, etc.) and let ummm rip?


I would calculate the volume of the greddy intercooler and compare it to what Treadstone has for similar volume and dimensions and correlate it to one of their many available intercooler...my gumption is that the greddy IC is sufficient for for well into 1000hp

I'm running a treadstone 1235 (22"x12"x 4.5") and it's rated at 980hp and this IC is noticalble smaller than the greddy IC.

 

Im in Canada so we have pump 94 instead of 93, however there are only about 5 or so E85 pumps across the country that I know of, hence why I'm using 94.

I know of two cars for sure making 742whp and 750whp on pump 93. One with a 6870 and the other with twin 58's, so I believe with twin 67's and the supporting mods 750+ is definitely possible on 94.

Im not sure I follow you about the ignition timing issue after 23ish psi? I could understand if IAT's were high or something, but with a 8.5:1 compression I see no reason why knock values would go up until 30-40 psi. However I've been wrong before, I'm just curious if there was a specific reason VQ's have a problem above 23 or so psi, since so many other motors are fine at that level.

At 600whp my tuner explained that I had the lowest knock values he's ever seen, regardless of power, however that changed when the IAT's climbed. When we let the car sit and cool we could do 20psi pulls and make 630-640whp without knocking, however that wasn't reliable for consecutive pulls.

Also I agree that the Greddy intercooler is larger, though bigger isn't always better really applies to coolers. The Greddy flows left to right, at a length of 24" I believe, so it has a large amount of drag and probably a decent pressure drop, which I can only assume will account to higher IAT's. It is also a tube/fin design which flows less air then the bar/plate design like your Treadstone. Im not sure what your Treadstone design is like but I know the good ones flow bottom to top so that they have a larger cross section but since they only flow bottom to top its much shorter which results in less drag, less pressure drop, and more efficiency.

 

I hear ya! we have 91oct other than at the tracks.

I'm not doubting you, but do you they have social media accounts, dyno vids, build sheets? Just curious on what theyre builds are! From my experience, guys pushing above 600 to 650 are running E85 or a race gas and/or have 3.8 liter / 4.1liter strokers.

Valid point, I didnt factor in compression ratio nor a higher octane fuel. Some? most? pump gas guys are limited to 91octane ... but I dont see pump gas guys pushing too much past 20psi to 22psi / +/-600hp to 700hp ... I have to speculate that the engine starts to knock at this boost pressure, and cannot take any additional timing. I think it's safe to assume that a respectable blowers can make more than 22psi

I've never seen a 350z running mid to high 20s psi boost on pump gas. E85, yes. Race gas, yes ... Not seeing knock until 30 to 40psi with respectable timing is unheard of...those are 4cylinder boost pressures!

Here's the list of top 50 FI builds ...
https://my350z.com/forum/forced-indu...50-list-4.html

You dont see pump gas guys until the mid-20s (out of 50) and they are pushing mid-600s. So to think you'll see 700hp to 800hp on pump gas (albeit 94oct) is unrealistic. I dont think it's because guys are running out of blower, cant flow the intake/exhaust, or IATs ... I think it's the VQ, boosted will only take so much timing.


so many other 6 cylinder or 8 cylinder engines? or 4 cylinders?


I can see 20psi making 640hp just fine on 94octane with cooler temps.

Just curious - what tuning platform are you tuning with?


all valid points (IMO) on the IC, 24" sounds about right, I think it's 5" deep and 10" or 12" tall. I believe bar & plate are better and I've heard members of the tuning scene say this as well. Side to side vs. bottom to top can be discussed and each have their positives & negatives. I would take a bottom to top if it didnt go over the radiator, and the VQ plenum was like a LS plenum.

Yes - less drag, less pressure drop, and more efficient but less time to exchange heat (which is a higher IAT?) I see it as a balance of everything previously mentioned and because I'm running a OEM-like charge pipe (IC to TB) I took a horizontal flow. Also it would really bulge out of the hood.

 

Marks G35 done by dynasty, featured in Apex magazine. And Who I believe has the record of 750whp on 93 is silva350z on instagram. Those are just the two I personally know of.

I mean I'm only talking 6 cylinders but for instance, the 2j ofcourse, vr38's, Barra's, rb's, whatever that inline 6 that patrols have lol. Theres quite a few for sure. Not saying its even easy in those platforms, but its definitely been done.

AEM Infinity 8. Also theres going to be two meth injectors involved as well. Only had one with the previous setup.

 

Beall, why are VQs knocking? I'm not too familiar with boosted VQs but as a mechanic I would think that if you have the proper plugs, ignition, CR, and cool IATs you would be golden. Kinda makes me curious, maybe it's the fact that people refuse to upgrade the stock ignition system, and say it's ok? IMO the stock ignition isn't all that great for high power and you want something with multi spark capabilities.

 

Right on - those are stout builds. I would reference that top 50 FI builds too, if nothing more as trends with these engines ... and obviously gotta factor in that there are DEs mixed with HRs...

The 2j is a much better built engine and are guys pushing 30+ psi on pump or on e85? The VR is a much more technologically-advanced engine (as compared to the DE) and are GTR guys pushing 30+psi outside of methanol or E85? I dont know much about the nissin patrol or the RB series but I think inline 6 engines are generally speaking stronger as they have main-caps for each rod (meaning a 2jz has 7 end-caps, where our VQs have 4), the jz is an iron block that flows significantly better (ie one side in, one side out) where the VQ is not nearly as efficient.

You should share your experience with the AEM, I dont know that anyone runs that here.

A healthy dose of water methanol will def help keep temps down, charge cooler, and charge more stable. I love WMI.



If you ask me (and I'm far from an expert) any engine NA or FI (regardless of MBT) is going to knock at some point if you continue to advance timing. It's just the nature of the beast...you can't have 50 degrees of timing on a gasoline turbo'd engine and expect it to work right ... and when you factor in increase boost pressure/compression ratio, and different grades of octane it's just a sweet-spot of what the engine will take. Of the handful of FI ignition timing maps I've come across it's anywhere from 15 to 20 degrees at redline depending on the aforementioned factors and no two engines are the same.

Increase boost or compression ratio, expect to bring timing in.
Increase octane or decrease boost you advance timing out.



man? ... I guess I would want to see what's out there for upgrades are available. The 350/370/GTR coils are towards the top for joules output arent they? (I think the unit of measure is joules) - I've heard that the AEM coils are better but not sure how much better? I'm not sure how the ignition system stacks up to others on the OEM or Aftermarket side.

Multiple sparks as in two sparks at the same time or two sparks (one after another). Doesnt the hemi use two spark plugs? but it's for emissions?

 

From what I read in that other thread the 370 and GTR coils are better than the DEs. I was talking about something along the lines of MSD, a lot of folks use that for domestics and some imports? Granted COP systems are good but being able to tweak dwell times and 2 separate sparks can't be bad. You can always use a sprayer to chill the fuel and IC. One thing I've been wondering since I've been seeing all the hybrid set ups is would it be possible to mate the VQ37 bottom end to the DE top end and run it successfully?

 

I don't think it's possible to put the DE head on the HR bottom. They blocks are way to different. Besides that you want HR heads. Stock HR heads flow more than ported DE heads.

There is a guy who makes adapters for Audi R8 plugs and claims they are significantly stronger spark than the DE. I think they are like 58Kv and the De is 41Kv...
https://my350z.com/forum/engine-and-...k-in-a-vq.html

 

Good stuff gents subbed.

 

They flow better but I don't want to do a HR swap, I would want the stronger block with all the DE electrical components so it acts like stock lol.

 

I use the R8 plugs myself, and the response is definitely noticeable on the throttle. Albeit that I haven’t had the chance to drive it on high rpm for the boost to show the real difference.

Chasing 800whp myself, I can’t really give any insight since I use E85.

 

Remember the heads is where the power is made.

 

Certainly but one can't argue with the fact that A) it's not as important on a boosted car as it would be on a NA car, and B) putting a whole VQ37, HR or GTR engine in a 350Z is not an easy task. If anything it would be more worth it putting the GTR engine in there since it's the best out of the box. Ultimately it's the chase of something like this that creates new trends. For your average owner a DE is enough, I know it is for me, my goal is 500whp using the HKS kit. Shouldn't be too complicated lol.

 

nahhhhhh ... ignition timing is where powaaaaaaa is made!!!

alright, alright alright ... a little bit of everything makes power - you're only as strong as your weakest link!

If it's something I've learned (and doing as best as I can) is to make things simple and as least complicated as possible. Also reduce and eliminate as many electronic components as you can ... meaning if you can do everything with a single device (ie a standalone) than that's fewer things to fail.

​​​​​​​

 

Totally agree, I'm on this stupid little adventure right now trying to integrate a nDash to my car, why you may ask...
I don't want any extra gauges anywhere, I want this car to look relatively simple, like a factory plus if you will. The nDash will be able to read the dual widebands, IAT and boost all in one display. Simple and sophisticated I say lol.

 

If the ATI's are High, then that IC in not doing the Job.

Look at the the TreadStone site. They make a very good Product for a good price.

I'm Supercharged @ 20 psi, Stock motor, with a TreadStone Tr-1245 IC, My ATI's are 8-10* above ambient on a WOT 4th gear pull.

Also, you need to Log ATI's during the pull, as this is when it Matter. Not after the Fact. Ati's will climb when you back out of the throttle.

Get the proper IC for the Job, on pump gas you need to keep the ATI's Down, And car runs much better overall.

TimRod

 

Yes, ignition makes power but....it doesn't matter if you run 30* of timing or 35* of timing you can only get so much power out of 10cfm of air. Whats the old adage there is no replacement for displacement? 15cfm is always better than 10cfm of air.

 

I hear ya and agree!

Old adage: No replacement for displacement
New adage: No replacement for a turbo, tune, and variable cam-timing!

 

LOL