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Adding a turbo/intercooler to my '95 Pathfinder


2milehi
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Sorry champ, didnt read the whole thread. just skimmed and assumed you dropped the DETT in it. Must of read something in another thread about the DETT swap? And what i was trying to ask about the MS ecu.. is it an easy ecu to tune, or does the amount of stuffing around with the ignition and fuel maps make you want to jump infront of a bus?

 

No problem - there is another doing the DETT thing and he just got it running a few weeks ago.

 

With the MegaSquirt, there is a lot you can do which means there is the potential to screw up. There is a learning curve and A LOT of support from forums to get you going. But once you learn how to tune, it does get a lot easier. Go to msefi.com and surf around, but the best teacher is experience. And with the low cost of a MegaSquirt, you don't need a lot of money to get a stand alone controller.

 

This is my third Megasquirt install and it took me about 2 hours with the Pf to get a decent tune that will idle and support 6 pound of boost.

Edited by 2milehi
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What an uphill climb to figure out what injectors I am going to use. And they were under my nose all this time. So I flowed both the stock Pf injector and the injector that came in a '90s 2.5 Subaru. The stock one flowed 180 cc/min and the Subie one flowed 265 cc/min. I bumped up fuel pressure from 40 psi to 50 psi. That will make the Subie injectors flow almost 300 cc/min and that should be good for 260 hp at the crank. Now to find 2 more injectors since the Subie came with four. Since the intake is off, it got a good cleaning and I get a better understanding of the hidden vacuum circuits.

IMGP2544.jpg

 

IMGP2545.jpg

 

Mean time I need to figure out how the Walbro pump fits in place of the factory one.

IMGP2543.jpg

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It looks as though the factory pump is larger than the Wahlbro. I have been researching pumps for mine, and it appears that the factory pump is a 45gph pump. While that rating may be slightly less than the Wahlbro, it may be enough for 300-350HP. I will be making a WOT run with mine with a fuel pressure guage on it and monitor pressure reading. If I have no pressure drop at WOT, I will mo st likely save my money and keep the stock pump. Is the factory pump really that much larger, or does it just look like it in your pic?

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So 45 gph calculates to 170 lph which is about a third less than the Walbro. Forty five gph calculates to 350 hp. IMO I would measure what comes out of the return while the engine is running. At idle not much fuel is used and the alternator is charging giving you more power at the pump. It should take 1 minute 20 seconds to fill that gallon container. And yes the factory fuel pump is a lot larger looking than the Walbro. Hope it fits.

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  • 3 weeks later...

Sorry I have been out of the country for 2 weeks and prior to that I had a week long out of state convention. I got back last night and I am still a little jet laggy. I did get some bigger injectors (370 cc/min) and just installed them. I will test them tomorrow.

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Here's a naive question... is there any "unbalancing" effect from having a turbo on only one side of a V engine? I guess having the turbo someone disrupts the exhaust stream, but presumably this has minimal effect on combustion in those cylinders...?

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Here's a naive question... is there any "unbalancing" effect from having a turbo on only one side of a V engine? I guess having the turbo someone disrupts the exhaust stream, but presumably this has minimal effect on combustion in those cylinders...?

 

Both banks of exhaust collect in to one outlet before the turbo, so all six cylinders do work.

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Both banks of exhaust collect in to one outlet before the turbo, so all six cylinders do work.

That is correct. In the below pic you can see that the left side of the turbo mounting flange is from the driver's side exhaust manifold. The right side of the flange is connected to a cross-over pipe that connects to the passenger side manifold.

 

IMGP2439.jpg

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That is correct. In the below pic you can see that the left side of the turbo mounting flange is from the driver's side exhaust manifold. The right side of the flange is connected to a cross-over pipe that connects to the passenger side manifold.

 

IMGP2439.jpg

 

Ah, I see, so the "up pipe" (pic was posted a while ago in this thread) connects to a pipe from the passenger exhaust down below the engine I guess?

Edited by sewebster
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Injectors are in and I have bolted everything back together. The 370 injectors are now flowing 410 cc/min at the higher pressure. A couple of hoses tore when taking the top part of the manifold off. I'll be trying my damnest to get the Pf running this weekend. I need to tweek the fuel map by reducing fuel flow to 44% of where it is now.

 

Man - nothing like a vacation and rental property to get in the way of progress. ;)

Edited by 2milehi
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I had to change the pigtails for the new injectors. I really try not to cut into the factory wiring harness, but I didn't have much of a choice.

IMGP2786.jpg

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I turned up the boost by adjusting the waste gate arm. Got to 11 psi with more headroom based on duty cycle :D

Nissan11PSI.png

 

I'll need to add a boost controller to get more boost. The Pf runs awesome.

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should make a good base map for others to follow suit and post it up since your kinda pioneering the way, i may dip back in to f/i engines again and the vg has a ton of potentual, that turbo is way to small i can say that must, ditch the divider in the manifold it will help with spool-time, a little larger bar and plate type fmic would make a big difference and needed for a larger turbo ie t3/t4 .68 ar or a gt 35, pathfinder would probibly work better with a efan swap and make for routing up pipe and inter cooler piping in front of the engine, if a person were to make up a fuel rail system to run top feed injectors we could run 450cc "Bluetop" DSM injectors, hell they can be bought for 45 a set or free from the JY lol they are also a high impedence inj., my hat goes off to you sir you have opened the eye of many, you may wanna think about putting together a MS ecu to market that has a base map on it, as i know for fact a few of my older friends have made a @!*% ton of money with ecu/tuning

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I used the stock intake manifold. I will make another post on a DIY MegaSquirt and post all info.

Edited by 2milehi
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I turned up the boost by adjusting the waste gate arm. Got to 11 psi with more headroom based on duty cycle :D

Nissan11PSI.png

 

I'll need to add a boost controller to get more boost. The Pf runs awesome.

 

How come the rpm rises so slowly (seems like it anyway) when you open the throttle? Can you explain the bottom six traces? I don't know the acronyms...

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How come the rpm rises so slowly (seems like it anyway) when you open the throttle? Can you explain the bottom six traces? I don't know the acronyms...

 

The graph is stretched out to better see what is going on.

 

Acronyms

TP - Throttle Position

AFR(WBO2) - Air to Fuel Ratio from a WideBand sensor/controller

PW - Pulse Width of injector in milliseconds

CLT - Coolant Temperature

MAT - Manifold Air Temperature

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alot of tuning to be done by that data log session, are you using any knock monitoring device if not i'm certain you could up the boost and gain alot of power and get the rpm more in line with working boost pressures, are you doing this tuning on the street or a dyno?

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