why do guys with front mount turbos talk about how it's not worth running headers cause the bigger tube hurt spooling

I know you want a good free flowing exhaust after the turbo but what about before the turbo

 

thanx Nealoc, now im in the market for a muffler. was thinking about one of them dynomax bullet types. but i dont kno if they will lower volume that much.

t6378tp, I think the 2.5 piping that i have is fine, however eventually I will be wrapping the piping from the cat all the way to the turbo. This will drastically improve the spool since it will keep the exhaust heat inside the piping and therefore increase velocity and volume. There's a thread in the transam/camaro forums strictly about rear mount turbos' and ALL of the people that wrapped their exhaust piping from the front to the back, got drastic improvements, spool up came in alot sooner and more power was noticeable on everyone that did it.

 

A larger diameter exhaust manifold will reduce velocity causing the turbo to spool slower.

 

oh i thought you were talking about after the turbo.

before the turbo you have to strike a balance between velocity and backpressure. backpressure is always bad for power production, but the pressure differential between before and after the turbo is what imparts energy to the turbine wheels and spools up the turbo. so you don't want too much backpressure or it will lower your power output, but you need that high pressure differential to spool.

i have no idea what would be optimal on a rear mount car.

 

does anyone have the formula for calulating air velocity and volume I know if a search and ask around and find it but if some-1 already knows it would make things easier

 

With exhaust gas velocity you want the exhaust gasses to stay as hot as possible BUT without being restricted in flow. As your exhaust cools down the molecules become less energized and move more slowly. This is why people don't run 5 inch catbacks.

The diameter of the stock size of the exhaust side of the header is fine, if you added them all up it would probably be larger than 3" anyways, the big dogs don't even use larger header sizes (that I am aware of). The main concern is equal length runners. This makes a serious power difference on in power on forced induction and decreases spool time. I saw a tuning experiment turbo honda making about 440 on 26psi on a log style turbo manifold, he switched to an equal lenght manifold and made over 40 more hp on the same exact setup.

 

Some do. But we're talking about overkill on 1000+ WHP Supras and turbo-diesels and what not. Continue on

 

is there a starter-kit in the future?

 

The problem with anything in kit form (even basics) in the Maxima community is that everyone here is cheap and rarely keeps their word and ponies up the cash later when they say they are interested in something. This gives very little incentive, even to those not looking at profit, to do anything in more than single quantity. So my guess: no.

 

What you need:

t3/t4 turbo
correct flanges
welder
oil lines/ pump
370cc+ fuel injectors
tuning

Basically thats all street is running correct?

Oh and BTW very impressive numbers! I read the other thread and it looks like its doing very well considering the effort to make it to boost. Lots of props man, it seems to be working very well! Im sure your giving up some spool but the fab costs and under hood temps are sacrifices that need to be made :P

~Alex

 

Thanx, yea my problem is only at the 60' since thats where im not boosting. the secret is in a high stall TC. if I could just come off the line with at least 1psi or at least 0 vacum, that will drastically improve my launch and 1st half ot the 1/4.

as for my setup. i have a T04B turbo, the scavange pump, used nitrous line for turbo oil feed, thick ss line for return into the pump. then regular tranny fluid hose from pump to front valve cover, check valve on feed, charge pipe was bought for 30 bucks (three 7' long pieces then i cut myself), i used radiator hoses as couplers and also for turns (90degree's).

The car is running awsome. I am loving it. i just need that high stall. i mean the lag is not THAT bad, I will always have bad 60' with the rims i had. 50lb each with tires!!! I will go back with the 22" slicks mounted on the sawblades (37lb total) and see what i run. i predict high/mid 13's.

 

streetz do you plan to dyno again

 

Nope, no plans to dyno anytime soon. unless we get another dyno day ($40 bucks for dyno), 1/4 times is what counts to me, and i tune the car myself so no need for dyno.

 

Do you have pics of the finished setup?
Is the turbo supported by the pipes only?

 

The turbo is supported by the exhaust outlet. I have pics on the first page of this thread where u see the pipe coming out the turbo and towards the stock tip location. thats the finish setup. I got good strong hangers on that pipe.

 

streetz do you think that you have about the same clearance as a front mount turbo setup.

how much lower does the charge pipe hang than the exhaust pipe

 

THeres a kit from Korea I believe for the VQ25 that I know a member had on his, and from what I heard it was a nice little kit. Doesnt push the uber boost so many on here dream of, but for everyday driving I think it would be perfect, and Ive been toying with the idea of trying it myself..............

 

got any more info on it? or a link?

 

I only found it once, and its not sold here in the states. He was from Korea and brought it back. Maybe someone from the NJ area will know who Im talking about and have better info than I do.

 

UPDATE: Well today makes 2 months with my setup and here is what has gone down during this time.

Oil problem I had, now solved!
I have installed a turbo timer from ebay to leave my scavange pump running 2 minutes after the car turns off, this has completely eliminated oil from my charge pipe. I was leaving the pump run about 40 seconds after car was turned off, but it was not enough to remove all the oil from the lines, so over night or parked for long time, oil was leak thru the seals and go into the charge pipe. so im happy about that.

No more lag
After tuning below 3k RPM and also above 3k, the car actually dosnt have that much of a lag at all. Boost still starts developing at around 3k, but since i tuned below 3k to close to stoich or slightly richer, the car gets to 3k ALOT quicker than when my o2's were blown. so the lag is not even noticeable, it pulls very smooth. I have ordered header wrap and will be wrapping my entire catback, this will drastically improve how quick the turbo spools up (proven by everyone that has wrapped catback on rear mount turbo). I already painted the pipe so now i just need to wrap it and paint it again to protect it.

The auto
My auto is still holding on strong. No signs or any complaints from it at all. Ofcourse if im pushing it like at 60% throttle without the drop resistor being activated, then yea it will slip between the shifts (already in boost), but thats because the drop resistor is not being activated. My plan is to move the switch i have so that instead of the drop resistor getting disconnected at 70% throttle, ill have it like at 40% throttle. This way the tranny wont slip at part throttle and have instant shift, and also help prolong the life of my tranny.

Future plans
Well, for now. I am not going to increase the boost. I am really happy on how it performs at 7.5psi, which means I wont be doing meth injection anytime soon. I need to change my timing chain tensioner because I think i am due for it. 140K miles, and I am also getting a slight rattling noise from inside the timing cover near the back exactly where the tensioner is located.
I also plan to cover my charge pipe with a thermo shield like how i30krab had(or has) on his supercharger piping. When i pop the hood and touch the pipe coming up to the engine bay and into the maf. it is EXTREMLY hot because of the engine bay's temperatures. How ever, if i touch the piping below the car or even close to the turbo, is it not hot at all, even after a run. So im thinking that the air is cool going down the pipe, but when it goes up into the engine bay it warms up. hopefully by wrapping it, i can lower temps a lil bit (might not notice it but still worth doing)....

well this concludes my updates and plans. thanx for reading. pz

 

good luck with your project, the best thing to hear is your happy with the results

 

Awsome job!
Oh not to highjack at all, but the turbo kit I was refering to was made for the Samsung SM5, which is basicly the I30\Maxima made by Samsung, and uses the VQ25.
They even have a website you can buy parts from if you can read Korean. (Still looking for the turbo kit though)
www.sm5club.com

 

Quick question about the tensioner issue. Are you using Dino oil or synthetic? I'd bet you the whole car that if youre running synth, and you changed to Dino, the rattle will go away. (Ask me how I know that trick )

 

Never should one run a turbo setup engine with dino oil, always synthetic. Remember the turbo itself gets pretty hot due to direct contact with the exhaust gasses (which can EASILY go over 1000*F). Proof being, when this RMT was assembled, he changed the oil shortly after (dino castrol gtx) and it literaly came out like water. Replaced with Mobil1 and the oil is holding up just fine right now. Dino oil can handle the engine's temperatures, but not those of the turbo itself- general concensus.

And even IF switching back to dino oil fixed it, this doesnt fix the fact he might have a tentioner thats on its way out. It's like adding thicker oil on motors with bad piston rings. It covers the problem up, but it doesnt fix it, its still there. Dino or synthetic oil it should not be making noise... so its getting changed

 

Great, and your helping me!

 

I was going to... until you did that double post, what a n00b j/k lol of course meng

 

Wow what a ride, thanks for meeting up with me. I finally got the chance to see your ride in person, very very clean indeed. Man I remember when we were all stock and now nobody's playing any more. Now I can say almost the whole crew has their car seriously modified.

Seriously I was more surprised of how quick the tranny was shifting. I've driven in a few tuned Auto's and never seen an auto just keep pulling after shifts as hard as yours. Having that TC lock up switch must really help. Anyways good look on your future mods it's only going to get better from now on. lol

 

We take our autos seriously these days

 

Yeap.


12345

 

I third that - and you ain't seed nuttin' yet........ Heh.

 

the souf shall rise again

 

Do you have any engine bay pics?

 

Nothing special under the hood, lol. Just look at any picture of a 4th gen engine bay with an 00VI and an Injen CAI. Its not really an injen CAI, thats the charge pipe that comes up front infront of the tranny up to the TB, lol. Oh yea, and picture a spaggetti of miscelenious green, white, red, black, and more green wires all over the place, bundles up in white electrical tape. That's his engine bay pretty much

 

This is a general idea of how my car is running right now. The opponent is a Evo IX with two step limiter set at 4k rpm, and a basic computer reflash. From his launch he gets me real good, the entire run I was at around his rear door. I kept on locking and unlocking the TC to see if it made any difference, which was a mistake because u gotta leave it locked the entire run to get benefit from it. we had several other runs with similar results. then from a roll, but i left my shifter in 1st and hit limiter couple times so he got me by a few cars and i never caught up, from the launch from a roll we were really even though.

http://videos.streetfire.net/video/1...f30145c689.htm

 

nice, great job with the car

so whe r u going back to the track

 

Looks like you're finally getting it where it needs to be. Can't wait to see it with the tweaks you have planned.

 

UPDATE, Well like I mentioned before. I finally wrapped my exhaust piping with header wrap. i basically wrapped the entire Bpipe. as for results, wow, definitely worth it. It feels like i got slightly more power now, in 1st gear i spin more than before (normally i would just chrip them when boost came in), and the turbo is more responsive. spools up really quick. also spools up maybe a couple hundred rpms sooner.

 

Is your BOV doing well? I'm trying to figure out which one to go with, and from my research, the turboxs is pretty much the loudest, and i love BOV sound so louder=better. Wondering if it lasts though.

 

i love it. get it if u like it loud. its loud as ****. iv made lil kids on the sidewalk jump LOL. and i dont see how it would go bad, its just a valve that is controlled by vacum or pressure. nothing really to it, with the right tools you can probably even build ur own lol. simple design.

 

yes i know im newbie but im ok with it...... i have decided to do this rear turbo setup on my max. ive begun ordering parts via ebay (gotta love ebay) not too exspensive to do this setup.any updates on fuel delivery?? nevermind the fuel delivery Q i read wut u did sry