Supercharged/Turbocharged The increase in air/fuel pressure above atmospheric pressure in the intake system caused by the action of a supercharger or turbocharger attached to an engine.

Garrett T25 non-intercooled on VQ35

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Old Oct 2, 2007 | 05:44 PM
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Garrett T25 non-intercooled on VQ35

It seems to me like there are a lot of people here that want to run 10 PSI, and be in the 10's in the 1/4 mi. I'll be the first to tell you, I don't have the knowledge or drive to shave 4 seconds off of a modern engine's stock 1/4 mile.

I have been doing some research to see if I could possibly custom-fit a turbo onto my VQ35. I would much prefer a supercharger, but the amount of fabrication required for that would be beyond my database of knowledge. I am pretty confident that my father and I have the mechanical know-how and trouble shooting abilities to tackle a small turbo project on my car. As I was doing my research, I figured that I would start by studying the factory VG30DET and the VE30DET setup, to get an idea of what I am looking to fabricate. As I was reading about the t-VG, I saw this...
The 3.0 L (2960 cc) VG30ET was available in early production with a single Garrett T3 turbocharger and a 7.8:1 compression ratio. The USDM version produced 200 hp and 227 ft.lbf. In 1987 it changed to a single Garrett T25 turbocharger and an 8.3:1 compression ratio to reduce turbo lag, and was bumped to 205 hp and 227 ft.lbf. No VG30ET was ever factory equipped with an intercooler as they featured low boost pressure for fast response.
This got me thinking, If I am only running on a max of 4-5psi, then that would aleviate a lot of my potential fabrication. So, my question would be these

1. The VG30DET has obviously stood the test of time, and it is still one of the most reliable motors ever made. Properly fabricated of course, could a 4-5 psi non-intercooled turbo setup work with no detriment with regards to heat buildup?

2. With such a low boost setting, are larger injectors still necessary if the Emanage U has a correction factor of +/- 20%?

3. I shouldn't be worried about maxing out my MAF voltage with such low boost should I?

4. With such low boost, a boost gague wouldn't be necessary, because I want a stock sleeper look to it. Correct me if I'm wrong.


Obviously I'll have to use a wastegate, BOV, and I'll get a turbotimer and Emange U, oil circulator.

But do I need to intercool 4-5 psi? I'm only looking for 40 or so HP at the wheels which is what I should expect. The same with injectors, fuel pump, MAF?

EDIT: and I'm also fairly certain that my stock 2.5 exhaust setup will be suffecient for this amount of boost?

Last edited by bwinter7; Oct 2, 2007 at 05:47 PM.
Old Oct 2, 2007 | 06:23 PM
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ok im sorry a t25 would not work on a vq35. YOu should look into something like a t3 for a decent mid and top end. A t25 may would spool at 1500 rpms and drop like a rock after 4500-5000. Yes if your going to run under say 6psi you may could get away with no intercooler. But im sure after you feel boost you will want to go up. Stock injectors may work for a while but I would get a fpr with a 1:1 ratio to help. A boost gauge is always a must to me just to moniter boost levels. If it start creeping up you will have no way to know other than the car may feel a little faster but if it 1 or 3 psi you maynot at them low levels!
Old Oct 2, 2007 | 06:54 PM
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Originally Posted by 95turbo gxe
ok im sorry a t25 would not work on a vq35. YOu should look into something like a t3 for a decent mid and top end. A t25 may would spool at 1500 rpms and drop like a rock after 4500-5000. Yes if your going to run under say 6psi you may could get away with no intercooler. But im sure after you feel boost you will want to go up. Stock injectors may work for a while but I would get a fpr with a 1:1 ratio to help. A boost gauge is always a must to me just to moniter boost levels. If it start creeping up you will have no way to know other than the car may feel a little faster but if it 1 or 3 psi you maynot at them low levels!
Got it, thanks for the suggestion. I just really didn't want a big, honkin turbo with the capacity for 30psi. I want something with the exact streetability of my current max. I think that 4-6 psi should be a good start. But I'm sure you're right about once I feel boost, I'll want more lol.

I will start looking for good quality fpr's, do you have any suggestions?
And about the boost gague, I will get one. It's not that hard, it's only vacuum. I guess I'll just have to find a stealth place to put it.

Now, I'm going to do some more research on how to make a manifold. I wonder if I could just port the stock headers a bit, weld in a 3 to 2 collector in front and route the exhaust that way.
Old Oct 2, 2007 | 07:03 PM
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This is what I'm thinking now, am I off to a good start?
T3/T4 57 Trim Garrett tc
38mm Wastegate
Custom turbo manifold (maybe mr. Catts can help me out here?)
bov
Bov flange
down pipe
Charge pipe from turbo to throttle body
aeromotive fpr
Emanage-u
Old Oct 2, 2007 | 07:03 PM
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From: oburg S.C.
Originally Posted by bwinter7
Got it, thanks for the suggestion. I just really didn't want a big, honkin turbo with the capacity for 30psi. I want something with the exact streetability of my current max. I think that 4-6 psi should be a good start. But I'm sure you're right about once I feel boost, I'll want more lol.

I will start looking for good quality fpr's, do you have any suggestions?
And about the boost gague, I will get one. It's not that hard, it's only vacuum. I guess I'll just have to find a stealth place to put it.

Now, I'm going to do some more research on how to make a manifold. I wonder if I could just port the stock headers a bit, weld in a 3 to 2 collector in front and route the exhaust that way.
on fpr i would go with no other than aroemotive thier about 120 on ebay and thier great I have one for three years now.
Old Oct 2, 2007 | 07:20 PM
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Originally Posted by 95turbo gxe
on fpr i would go with no other than aroemotive thier about 120 on ebay and thier great I have one for three years now.
So this model series, correct?
http://cgi.ebay.com/ebaymotors/Aerom...QQcmdZViewItem
Old Oct 2, 2007 | 07:23 PM
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From: oburg S.C.
Originally Posted by bwinter7
yep its a good one!
Old Oct 2, 2007 | 07:27 PM
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You're being so vague. You make it sound like the size of the turbo determines the PSI or something. Seems like you're off to an ok start, but before you delve any deeper into your plans I suggest some reading.
Old Oct 2, 2007 | 08:02 PM
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As a reference you could look up www.cartuning.ca (yes, .ca not .com They're a Canadian company) They make a base non-intercooled kit for the GM 3800 V6. I was thinking of this kit when I had a Grand Prix. You can read some of their faq's on whether or not its safe to run a turbo w/o intercooler ( it is to a degree) and get some ideas for you custom install.
Old Oct 3, 2007 | 09:48 AM
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Originally Posted by Tatanko
You're being so vague. You make it sound like the size of the turbo determines the PSI or something. Seems like you're off to an ok start, but before you delve any deeper into your plans I suggest some reading.
I'm sorry if I'm being vague. I know what I want to do in my head, but it's hard for me to properly explain what I'm thinking sometimes.

I am thinking that the size of the turbo is important, along with the placement of the turbo. I don't want a huge turbo that'll fully spool at 4k. I'm looking for more low-mid range, and after reading up on different garrett turbo's, I think that the T3/T4, for the lightweight T3 turbine wheel and the high-airflow characteristics of the T4 compressor. I am thinking that I want to keep a 57 trim, while going with a slightly smaller a/r, to help with boost at lower rpms.

If I don't select the right a/r ratio, once the turbo is at full boost, and rpm's, go up, that will create drag and effectively choke the engine at high rpms. If I choose a t3/t4 57T with a .63 a/r, that should give me what I'm looking for, right? If the turbine is at max rpm, will I have the same HP as stock at high rpms or less?

And jr schultz, I'll look into that once I get to work, thanks for the link.
Old Oct 3, 2007 | 05:28 PM
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OK now, I've been reading about the VQ35 altima turbo kit, as I'm sure the people who are reading this already know. I guess now I have made the decision to go F/I, with a sleeper look, no bodykit or loud rims, (but the nismo rims will be in my future ). I read in another post that an economical way to gain a few horses from the VQ35 is to remove the precats, and put 4th gen headers on them, but I will also need a 4th gen y-pipe.

Seeing as how I don't really want to change the rear manifolds, I don't suppose it would be possible to keep the stock rear manifold, and put a VQ30 front manifold on, and weld in an additional piece to connect to the stock y-pipe?

If I can do that, then I can almost certainly use a VQ30 turbo manifold, but then reading on this specific manifold, (http://www.importperformanceparts.ne...an-nissan.html), I cant use my original t3/t4 idea, I would have to use a T25, T25BB or a T28BB. I know that 95turbo GXE said that having a T25 trim would not work as well as I am anticipating, that the boost would drop severly in the upper-range rpm. Any suggestions?
Old Oct 4, 2007 | 05:09 AM
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I believe that you can buy an adapter plate for the t-25 trim to the t3/t4 on ebay somewhere. Just an idea but look at the turbo specialites turbo kit and see if it would be possible to buy just the piping as people have already bought that kit and love the piping but suggest a larger turbo.

Good luck with your build.
Old Oct 4, 2007 | 06:30 AM
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http://www.ztspeedandfab.com/Products/Turbo_Flanges.htm
Old Oct 4, 2007 | 09:05 AM
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Originally Posted by Blackmax1924
Just an idea but look at the turbo specialites turbo kit and see if it would be possible to buy just the piping as people have already bought that kit and love the piping but suggest a larger turbo.
I believe the person who bought and reviewed the kit discussed it with Turbo Specialties and they were willing to make huge discounts if you didn't buy a turbo and a few other small components with the kit.
Old Oct 4, 2007 | 09:42 AM
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http://www.importperformanceparts.ne...an-nissan.html

Can I use this manifold from a VQ30DE? Obviously I'll have to get an adapter flange (thanks kzoosho) to make it work.

If I can, then I think that I will start accumulating parts for this build.

And one more question (for now ) 95turbo GXE said that I could use my stock injectors for now, but would get a fpr w/ a 1:1 ratio to help. Would you think that just buying some 440cc injectors now could aleviate some problems down the road? And the EU will be able to correct for that, correct?
Old Oct 4, 2007 | 11:18 AM
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I would stick with your current. 440 could b too small if you want to upgrade on the future. The stock ones will work great with your current goals
Old Oct 4, 2007 | 11:19 AM
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Anyone???? I know it's only been 2 hours, but I want to start spending some money and getting my project on wheels!!!!
Old Oct 4, 2007 | 11:28 AM
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no buddy the motor mount will be in the way to hang it from the manifold
Old Oct 4, 2007 | 12:28 PM
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Originally Posted by bwinter7
http://www.importperformanceparts.ne...an-nissan.html

Can I use this manifold from a VQ30DE? Obviously I'll have to get an adapter flange (thanks kzoosho) to make it work.

If I can, then I think that I will start accumulating parts for this build.

And one more question (for now ) 95turbo GXE said that I could use my stock injectors for now, but would get a fpr w/ a 1:1 ratio to help. Would you think that just buying some 440cc injectors now could aleviate some problems down the road? And the EU will be able to correct for that, correct?
not a problem man. I got a flange from them on my turbo setup and love it. its a transitional flange so i dont have to weld a round pipe on to a square flange. heres my setup.
Old Oct 4, 2007 | 12:47 PM
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Ahhh, very nice, that pic helped me figure some things out.

I just talked to my local speed shop and they can make me a custom manifold for $250 with my existing setup, so that's one less thing I have to worry about for now, and I will keep my stock injectors until I want more boost.

Well, I've got my fuel pump, t3/t4 w/ piping and an intercooler, (I'm sure I'm going to want more boost eventually, so I should have it for when i want it) and EU on the way, I'm going to relocate my battery tonight, and I will have my manifold made monday, (its OK if I have them block off the exhaust port with something Until I'm ready to install the turbo, right?) If not, there's a local junkyard that has a 3.5 manifold that I'll give them instead of the one on my car. Thanks for the help people!!! I should be boosted in a couple of weeks (In a perfect world, but, I'm sure we all know how that goes lol)
Old Feb 27, 2009 | 07:01 PM
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must have not gone well
Old May 5, 2009 | 05:34 PM
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bwinter7's Avatar
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Originally Posted by timbrooks77
must have not gone well
No it didn't.

Over a year ago, I was driving on I90 when a guy made a u-turn with his child in the car. I hit him at about 60mph. When I woke up, It was 3 weeks later. I was told I shouldn't be alive, that the only part of the car not destroyed was where I was sitting. I broke my left femur, both ankles, 5 ribs, and left collar bone. I got away lucky, his 6-year-old child did not. I have had to live with the fact that even though it wasn't my fault, and there was nothing I could do about it, I took the life of a child, so no, the build didn't happen.

I finally learned to live with myself a year later. I don't know if I still feel the same need to go fast. I saw what happens at 60mph. The Max saved my life, but took someone elses. I will buy another maxima, but I only started driving again a few months ago. We'll see what happens.

-Brian
Old May 5, 2009 | 05:42 PM
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That is a sad story man. I dont even know what to say....
Old May 7, 2009 | 07:55 AM
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Wow B-

Sorry to hear what you went through. Good to see you still with us though.
Old May 7, 2009 | 12:32 PM
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sad man... Glad your still with us
Old May 8, 2009 | 11:12 AM
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Really sorry to hear that. Can't imagine what thats like to deal with.

I'm a firefighter in Ottawa, ON and I'd have to say that alot of people assume that if they are a good driver that they can be cautious enough to avoid a bad situation (not refering to you, just speaking in general). But sometimes things happen that you just can't avoid. Unfortunetly, that kind of thing happens to often.
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