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Thread: Last Big Upgrade on the Sentra

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Posts: 11-20 of 27
2009-12-25 04:25:07
I think in general you're on the right track. I'd like to see a tubular manifold instead of the log manifold, but money is the issue?

If you're really gunna ball out with the 4" exhaust and go all the way to the rear bumper with it, I don't think you should need any oval pipe. There is no place under there where oval pipe will help. Save the money and don't use any oval pipe. If your budget is the issue, what ever you do, don't try to use 3.5" pipe as it costs much more than 4" pipe I believe. That being said, I've ran a 4" exhaust before on a BMW and I'll say I wouldn't attempt it on a B14 unless I absolutely had to. If I wanted to push the limits I might do it, but oh so many people make the 400-500 WHP numbers with a 3" exhaust. Yah it would be easier and everything would be "better" with a 4" exhaust but you should really ask yourself if that's going to be worth it for you.
2009-12-25 04:43:46
The oval pipe is for right under the engine. There is no way 4" regular pipe will fit under there without getting completely raped by speed bumps. 3.5" pipe is cheaper, but only by $20 per U-J bend and 5' section of pipe. Do you have any ideas on how to run the 4" under the engine without it scraping all the time? Maybe make some sort of skid plate that comes off of the crossmember? By getting rid of the oval I save about $300 because of the 5' pipe being $200 and the transitions being $30 a piece.

What exhaust manifold would you roll with? The revhard I am looking at is a mix of a shorty tubular and log manifold (for sale by SeenSense at the moment). I'd like a twin scroll but I can't find one that is under a $1000. I'm trying to stay under $2500 for this whole upgrade.

What are some good 740cc injectors? The Nismo ones?
2009-12-25 04:52:50
I didn't see you were on Progress coilovers before. I assume you're lower than the RM/AGX combos out there. If you were on RM/AGX I'd say you'd have plenty of room for 4" pipe under the engine but maybe not if you're lower. As for an oval pipe, I don't think you'll have the width between the cross-member and the lower oil pan. If it were me, I'd find some cheap 5" pipe from a truck bone yard and maybe use a press or hammer to square it off. I think a square is going to fit through that space better and give you the ground clearance. Then you can avoid paying for the transitions if you cut pizza slices out of the ends of the pipe and transition down to 4" that way. I'm just not sure how many tools you have available to you and how much time you want to put into it or how ghetto looking you'll accept. =]

Show us this manifold you're talking about. Link?

Nismo 740cc injectors are good, for sure. They're just expensive. But I've never priced injectors that size in side-feed configuration so I'm going to be no help there.
2009-12-25 05:02:13

The front end of the car is little higher than the rear, but the flex pipe on my downpipe from my original setup was always scraping on speed bumps. It may not have been tucked all the way up though. I can always flatten the pipe as I need to get it to fit.

What injectors would you go with if I were to get a top feed fuel rail? I'm looking to save money. Sidefeed injectors are around $600, if top feeds with a rail are less then I will do that.

I have a tig welder, plasma cutter, mig welder, BFH, along with any tool I need. I don't want it to look "ghetto," but if it needs to be done for it to fit then it needs to be done!
2009-12-25 05:18:24
If you're at all handy with those tools you can make the exhaust work and make it look good for a lot cheaper than buying oval pipes and transitions. Make your own. =]

Oh yah that manifold... It's better than a log, but not as good as a tubular manifold with a proper collector. If the price is right, then go with it.

For top feed fuel injectors you can't beat flow matched Siemens or Delphi for bang/buck. Get 8 and sell 4 of them or buy them from a place that sells 4 at a time like this: Acceleronics sells flow matched injectors

Here are your conversions:

70 lbs. per hour is 735cc
72 lbs. per hour is 756cc
75 lbs. per hour is 787.5cc
80 lbs. per hour is 840cc
2009-12-25 05:24:37
Will those injectors work well at 4bar? Those are really inexpensive! Are the Delphi better than the Siemens, or are the Siemens better? Will they require resistors? What kind of plug do they use? I can't seem to find a top feed fuel rail that will work with the Nismo AFPR. Would I need to get another unit? Custom Steel doesn't make the adapter for their fuel rail anymore...

That manifold is selling for $400, so if you know of one that is going to be absurdly better for that much or maybe up to $1000, post me a link .

Thanks for all your help!
2009-12-25 05:32:31
I wouldn't say Siemens or Delphi are any better than one another.
I know JGY (groan) made a top feed fuel rail that accepted the stock FPR at one point. I know because I saw one in person the other day. Maybe hunt down one of them?

I bet if you kept your eyes peeled you could find a decent tubular manifold for around $800 used... But that might take a while. I think this thing sold otherwise I'd have recommended it. =P
2009-12-25 05:57:36
Why are you sticking with 4 bar fuel pressure? Just get a top feed, and use a factory fpr.

I have used Siemens in the past and will on my current build. I like Racetronix, they have good service and I have dealt with them previously.

Here is an example of what I would get. 80 lb/hr High Impedance (no need for resistors)

Racetronix - 80 lb/hr D4 High-Z Fuel Injector MT

$50 per injector.

As for the fitting the 4" pipe under the car, I would use normal pipe and run a skid plate. You will regret doing something like hammering 5" pipe to fit. Worst idea evar.
2009-12-25 09:04:50
Do these style injectors come with connectors w/pigtails or what?

I remember the JGY rail, just have to get one without getting shafted I suppose.

I like those Sidewinder manifolds. What about the normal lovefab manifold for $999?
2009-12-25 09:10:32
Dude we can make you a twin scroll manifold for that much

You can pick up the injector clips at:

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