450Z update

[450Z]

I know I don't post here as much as I could, but here is an update of my 450Z project.Since I got the car back from the paint shop (06 Dodge R/T mango) I've run in 2 autocrosses and one track event in the wet. The car is very strong in every way, although after the first event I found that the right front shock is "toast". I don't believe that I have bottomed it out. Still sorting some things out.The VH45DE engine is running very strong especially since I got Elwesso's NICO ECU in it. It revs like my old L30 engine, yet has tons of power everywhere in the power band. Many people have a hard time believing that this engine came out of a big Nissan sedan! Still trying to find the best compromise of sound/back pressure for the engine.I now have to make the roll over bar and then tackle how I'm going to integrate the stock wiring into my aftermarket fuse box. After which I'll throw in the an interior.My hope is to have it street ready for the Z Car Convention in Cleveland this year. Mid Ohio track should be fun.............http://www.cardomain.com/ride/563982Thanks for all of the info you guys have been posting here, it's been a great help.

[mtcookson]

Still trying to find the best compromise of sound/back pressure for the engine.

That's easy... loud and none!

Really though, you could setup a relatively quiet exhaust system for cruising then get some electric cutouts for racing situations to open up the exhaust for maximum performance.

[craigztoyz]

Looks great, like the color, more pics of new paint please.

Open pipes, kill torque, as you have no backpressure, but accelerates quicker. I know some say no to backpressure, but you need a certain amount.

Glad to hear the engine is holding up, and thanx for helping my decision on a wes ecu.

[450Z]

Looks great, like the color, more pics of new paint please.

Open pipes, kill torque, as you have no backpressure, but accelerates quicker. I know some say no to backpressure, but you need a certain amount.

Glad to hear the engine is holding up, and thanx for helping my decision on a wes ecu.

The problems I have with pics of the car, is that I can't seem to get a good one that really catches the true color of the car. The videos are fairly good though. As for the torque issue, your right. I'll do some more experimenting with the suprtrapps as the stock cams will not work too well with open exhaust. The difference between the stock ecu and the Wes ecu is very noticeable.

[Mettler]

Nice man, I've been keeping an eye on your videos for a while... the car sounds so nice, looks like it goes great too!

Ugh... 'backpressure'

What you want is an exhaust system designed for optimal flow, using roughly the correct diameters to keep the exhaust gases moving fast as they cool down.

On mine I go for an initial 3" collector section, before reducing to 2.1/2" as the exhaust gases cool. Gotta keep those gases moving fast so they can exit the exhaust system rapidly without building up too much 'backpressure' against the engine.

The more power robbing pressure in the pipes, the more work the motor has to do to push the gases out.

Pic here

[maxnix]

That's easy... loud and none!

Really though, you could setup a relatively quiet exhaust system for cruising then get some electric cutouts for racing situations to open up the exhaust for maximum performance.

Actually, you can have fairly quiet and no significant back pressure also as the OEM exhaust attests.

[450Z]

Actually, you can have fairly quiet and no significant back pressure also as the OEM exhaust attests.

I agree, but I do not have allot of room for cats, resonators and muflers under this small car.BTW I uploaded some engine bay pics on my CarDomain site.

[450Z]

My concern is at what point will the ECU go lean because of lack of back pressure in the exhaust. I'm sure that with the stock cams it will be occurring. I guess I need to find a way to measure the mixture as I'm running, to make sure I do not damage the engine.

Ugh... 'backpressure'What you want is an exhaust system designed for optimal flow, using roughly the correct diameters to keep the exhaust gases moving fast as they cool down.The more power robbing pressure in the pipes, the more work the motor has to do to push the gases out.Pic here

[Q45tech]

Back pressure is only valid considering reversion during overlap and stock cams have 28 > 8 above 4600 rpm so immaterial.

Stock ecu has a 10 - 10.5:1 AF [to cool pistons] above 5500-6,000 rpm so a long ways to 12.5 A/F.

As I remember [10 year ago] oem back pressure at O2 sensor peaked at 9-10psi [277 " H2O] with all exhaust installed............leaving < 20HP worth of reduced output due to dual cats x 2 and entire exhaust.

[ultrapulse]

Thats worth knowing. I was alos going to say that with the std ecu tune, like all cars, you'd be pretty lucky (or unlucky) to have that much of a dramatic change to the mixture to lean out dangerously. My z32 TT was on a dyno recently and ran around 10.5-11.0 AFR, and it has gutted cats and a big cat back system. I think the ECU peak 'richness' is aiming for around 10.2-10.5 at full-noise.Basically most stock cars run such a rich tune that you need not worry.

[Carl H]

generally speaking nissan na cars target low 11's under full throttle and turbo cars target low 10's, lots of power to be had by a proper fuel tune.

[SuperHatch]

To add to what Carl said...

If Nissan tuned the ECU properly, a change in exhaust backpressure will have ZERO effect on AFR. Any increase in VE will result in more air flow through the MAF, the ECU will hit higher load cells, and will add more fuel to compensate. That is if the ECU hasn't already hit the highest load cells, then you would see a leaning of the AFR.

[450Z]

That what has me a little concerned. How do I know if I have maxed the Nissan engine map? On my last lapping day the engine was running hot (~230) and I though I heard the engine pinging. Was it temp related or rpm load dependent. I was running the engine hard in the 4000 to 7200 rpm range for about 20 minutes, was playing "cat and mouse"with a new Z06 on race tires.

That is if the ECU hasn't already hit the highest load cells, then you would see a leaning of the AFR.

[maxnix]

Need more air or a higher capacity radiator. What are you running?

[450Z]

I've ducted the entire front of the car so all of the air goes through the rad. It's an aluminum Griffon rad that the stock car races use, so capacity is not a problem. I spoke to one of the local rad shop owners who races a dirt modified. He believes that I need a higher capacity cooling fan system as the engine bay is so full that the air flow through the rad might be restricted. I had a 2000cfm 16" flexalite unit and now will be installing a 2500cfm system with twin fans. Hope to run it tomorrow and then back at the track on Thursday for a true test.

Need more air or a higher capacity radiator. What are you running?

[450Z]

forgot to include the engine bay pic.............

[nat0Z]

exhaust.........mmm....sounds flappy. (not flaming).may i suggest, maybe you should try 2 smaller resi's up front 10-12" long max, and another pair(same length) or into one large single @ back, this would get rid of the flappy flap noise your getting. But still keeping it loud and throaty at same time, without the flow restrictions of mufflers, tarp types.You can still mantain the silencing system you currently have for the diff dB you need at a given track.

Each time in my experience the 2-inline resi sytem lowers the note twice instead of once & then silenced, so you still get a fair ol rumble when you provoke it with a few revs and a bit on the right foot. this has been the case on a few examples, of 4's sixes and eights that i have 'played with'

How long are your front resis?as they look quite 'long' in the pics on your domain site. I would try just adding the 2 rear resis first up and seing how you like it, may not have to change the fr ones. but note and pitch of exhaust IS a personal thing i must say.

Just a suggestion,

nat0

[WizardBlack]

forgot to include the engine bay pic.............

What is your spacing like between the engine and the sides? Looking for info on this for my own '77 280Z project.

[450Z]

They are both about 16" long.I may have room at the back for 2 10" long res.I'll see what I can find here for a 2.5" tube. Seems I did not have allot of selection and that's why I ended up with these two.The sound is really starting to annoy me, but I'm running out of time to do this before the Z Car Convention in Cleveland, Sept30. Still hope to get the interior back in.If you want to here it at the latest event, I should have it uploaded to YouTube tonight. Just search for 450Z and StLAC

[450Z]

The engine fits very tight. I have about 1/2" between the engine and the strut tower on either side. My CarDomain site has a few pics that may help as well: http://www.cardomain.com/ride/563982/3

What is your spacing like between the engine and the sides? Looking for info on this for my own '77 280Z project.

[450Z]

Video is now up:http://ca.youtube.com/watch?v=ym4YSnwuU5gLets hope I can fix this to make the VH45DE proud.