Robb235's Front Mount Turbo Build

[Robb235]

This is something that's been in the works for me for quite some time now, and I figure I'm far enough along that it's finally time to post a build a thread.

I'm working on putting together my first turbo build, and my '99 4Runner is the candidate. I started out with a '97 Limited as my first 4Runner, and it was supposed to be the one I turbo'd, but unfortunately it was totaled at Fort Benning when a staff sergeant was hot rodding his Dodge Ram in a parking lot, lost control, and plowed into my Green Machine.

I was originally inspired to try my hand at turbocharging after reading [MENTION=75824]Clownmeat[/MENTION] 's rear mount turbo thread here. I love my 4Runner, but the 5vz is just too underpowered for me. It struggles on mountain passes, and especially trying to tow a boat over a small mountain. I love the 5vzfe, it's super reliable, but it's just a dog when towing or climbing mountains.

Video of me towing the boat here (does anyone know how to plug the Youtube video directly into this post, instead of just posting a link?):
http://youtu.be/2oiXn3jQOqY

So then not too long ago, CXRacing came out with a set of front mount turbo manifolds for the 1st gen Tacomas. Here is the thread discussing CX's turbo kit. Liking the idea of a front mount better, I abandoned the rear mount idea for several reasons. First, I didn't like being dependent on an electric oil pump to scavenge turbo oil and return it back to the motor. I felt that if that pumped failed while I was away from home, or even close to home, that could cause a very bad day. Secondly, I would never feel comfortable with a turbo that close to the ground in case it flooded or something. Didn't want to risk burying it in mud or sucking up water.

The only other potential option for a front mount turbo manifold came from RTI here on the T4R board. They had made a post about producing and selling turbo manifolds, and I like the idea of supporting local vendors and fellow enthusiasts. But when I contacted them about buying a set, they didn't seem too enthusiastic about actually making and selling a set, so I scratched them off the list.

So back to CXRacing. I Googled them, and they seem to be hit or miss on the quality of their products. Some people seem to have no issues, while others have received manifolds that didn't fit, or required rearranging half the engine bay. Not wanting to be the first to try these manifolds, I followed a couple build threads over on the one of the Tacoma forums, mainly GioGuitarDude's, but also StAndrew's as well.

They seem to be having good results so far, so I'm now confident enough to go with CXRacing's manifolds and downpipe (the $600 kit on their site), but I'll be providing my own turbo, wastegate, intake, etc. since I do not trust their Chinese turbo or wastegate. I've also decided to skip the intercooler for now. My goal isn't to run 20+ psi or anything crazy. This is going to be somewhat of a budget build, so for now my plans are to keep boost at or below 7psi. I'll continue to post progress of my build to this thread, and also bounce around any ideas that come to mind.

Thanks.

 

[Robb235]

So in keeping with the "budget build" mindset, I picked up a used turbo for cheap off of Craigslist. It's a Garrett T3/T04E, 57 trim, 0.63 A/R. I feel like this turbo should provide a good amount of low end grunt, and plenty of midrange, but might be a bit inefficient at higher RPMs. But that's ok since I don't wind out the motor very often.

You can see in that last picture I had to get a 2.5" 4bolt to 3" vband adapter, since the CXRacing downpipe has a 3" vband connection. I got it from Treadstone Performance, who carry quite a bit of handy adapters like that.


For the wastegate, I picked up a Tial 44mm MVR wastegate. Again, I had to buy an adapter from Treadstone to adapt the vband on the wastegate, to the 2bolt flange on the exhaust manifold. It has a 4psi spring in it.

 

[Robb235]

Like I mentioned before, I'm electing to negate the intercooler, simply because I don't feel that I need it if boosting 7psi or below. I've plugged my info and specs into a couple of online turbo calculators, and I think that my Intake Air Temps will still be lower than the supercharged guys. I'll monitor my IATs to be sure.

Basically my intake setup is like this:

(Turbo Compressor) -> (2" to 3" 90° silicone elbow) -> (45° 3" exhaust bend) -> (3" straight silicone connector) -> (Spectre MAF tube) -> (3" to 2.75" 90° silicone elbow) -> (Throttle Body)

Now here's the cool part. The Spectre 3" MAF Tube (part number 9405) comes with these "calibration tubes" so that I can match the MAF diameter to what the OEM MAF tube diameter is. The calibration tubes come in 2.25", 2.5", 2.75", and if you run it with no tube, it's 3". It's important to keep the MAF diameter the same, or otherwise the computer will think it's inhaling less air (if you go with a larger diameter), or more air (if you use a smaller diameter tube), throwing off your AFRs. I'm pretty sure that the stock diameter MAF tube is 2.75", so that's the size insert I'll be going with.

I scored some green-top 315cc injectors out of a non-turbo Toyota Cressida (same motor as the non-turbo Supra), which flows about 31% more fuel than the stock 240cc injectors. I got lucky and found these at the local pull-a-part. Whoever got there before me took almost the entire top end of the motor, but left the fuel rail and injectors placed neatly to the side for me to pick up :-D

Now here's an idea I've been tossing around. I can't just toss in those 315cc injectors, because they're going to be larger than what the ECU is expecting, and will likely throw a "too rich" code. Too bad there's no good way to tune these ECUs. BUT! I was reading lilevo's Land Cruiser turbo build thread over on the ih8mud forum, and what he did was increase the MAF tube diameter by the same percentage as his injector size.

For example, let's say you increase the MAF tube by 30%. Now the ECU thinks the engine is inhaling 30% less air, and injects 30% less fuel than it normally would. Now add 30% larger injectors, and it brings you back to where you need to be.

In my case, the 315cc injectors are 31% larger than stock. To change the MAF tube from the stock 2.75" to 3" would be a change of 19%. The 31% increase from the injectors, minus the 19% increase MAF diameter still means that the computer would run 12% richer than expected, however, I feel that the ECU could adjust for that via the Long Term Fuel Trims.

Anyone follow what I'm saying? Comments? The only problem that I can see is that with the larger injectors and MAF tube, the computer would be calculating a lower load, and might advance timing. But how much (if any) I have no idea.

Or I could just leave the MAF tube alone (leave it at stock 2.75"), put on the 315cc injectors, and just start running E85, lol. Would need an upgraded fuel pump for E85. I'll probably need an upgraded fuel pump anyways though just for more fuel flow required by the turbo.

 

[Robb235]

I found a guy selling a 5vzfe oil pan on Craigslist local to me, so I bought it back in the summer. I then bought a bung, and drilled a 1" hole in the side of the pan with this guy:

I then took the pan and bung to work, and asked one of the shop guys to weld it up for me. I put a cap on it until I'm ready to hook up the turbo oil drain line.

Then came the hard part: swapping out oil pans. [MENTION=112280]Link817[/MENTION] invited me over to his place and walked me through taking out the diff and reinstalling it. He's a stand up guy and I really appreciate his help, and allowing me to make a huge mess after my front diff dumped gear oil all over his garage floor. That being said, if I ever have to remove that front diff again, I'll just take it to a shop next time and have them do it. It's just that much of a pain in the ass. Here's the thread about changing oil pans.

 

[Robb235]

I've had the parts for a DIY water/methanol injection kit for quite a while. Last weekend I finally got around to mounting the pump next to the washer fluid tank. I tapped the tank (which is leaking at the moment, need to fix that), ran the lines from the tank to the pump. That's as far as I've gotten for now. My wife ended up killing the battery in her car by leaving the lights on, so she took mine for the rest of the weekend. I drained the tank and removed the fitting to let everything dry out, and now I need to find some kind of sealant that resists methanol to keep this tank from leaking.

 

[Supermoney]

Sweet, can't wait for more details to be posted. That is the thing with the 3.4, very reliable and dependable workhorse, but just a tad bit too slow! Any reason to skip the intercooler? They are pretty cheap.

Also after you get all the kinks ironed out, do you plan to push this setup to see what the 3.4 can handle?

 

[Robb235]

Sweet, can't wait for more details to be posted. That is the thing with the 3.4, very reliable and dependable workhorse, but just a tad bit too slow! Any reason to skip the intercooler? They are pretty cheap.

Also after you get all the kinks ironed out, do you plan to push this setup to see what the 3.4 can handle?

For now I plan on keeping boost relatively low, around 7psi or less, so I don't really think an intercooler is needed. I'll monitor my IATs, but since I have the methanol injection as well, I think I can skip the intercooler. It really helps to simply things and not have as much piping and stuff going all over the place.

I don't really plan to push the limits of the 5vzfe. I just want something that has a little more power to do what I want, and tow things where I want to go. By no means am I going to make this an HP monster or drag race this thing.

 

[Robb235]

I ordered the manifolds yesterday from CXRacing's eBay store. They had been out of stock for the longest time, but they finally got them in yesterday. Can't wait for them to get here!!

:hungry:

 

[IBallEngineer]

You know the computer doesn't "inject" any air right? It can only adjust fuel trim based on the air flow, throttle opening, veh speed etc.

 

[Robb235]

You know the computer doesn't "inject" any air right? It can only adjust fuel trim based on the air flow, throttle opening, veh speed etc.

Huh? Inject air? Where did I say that? Of course the ECU doesn't inject air. It only measures what the motor draws in via the MAF sensor. The ECU is calibrated to a MAF tube of a specific diameter. If you increase that diameter, the ECU "thinks" the engine is inhaling less air than what it really is. If you decrease the MAF tube diameter, the ECU "thinks" it's inhaling more air than what it really is.

 

[IBallEngineer]

For example, let's say you increase the MAF tube by 30%. Now the ECU thinks the engine is inhaling 30% less air, and injects 30% less air than it normally would. Now add 30% larger injectors, and it brings you back to where you need to be.

In my case, the 315cc injectors are 31% larger than stock. To change the MAF tube from the stock 2.75" to 3" would be a change of 19%. The 31% increase from the injectors, minus the 19% increase MAF diameter still means that the computer would run 12% richer than expected, however, I feel that the ECU could adjust for that via the Long Term Fuel Trims.

.

I don't know where I got the idea you said that, maybe this post?

 

[1985taylor1925]

Oh, how I like this thread. This is exactly what I have been wanting to do for the past few years now, and for the same reasons as you. Im also not crazy about the idea of a rear mount turbo for the same reasons. And I used to drive my truck all over the mountains as Im from WY, and like you said the 3.4 really struggles on hills and at high elevations. Years ago I was towing two dirtbikes up hill in the Rockies at about 7k feet on a hot day, and my radiator cap literally blew off. I initially thought I had ruined my engine.

I also remember that thread from RTI about building, tuning, and possibly producing a front mount turbo. I was really disappointed when that thread just died off. If I ever do this in the future (after an engine and tranny rebuild), I will use this thread as a reference.

Nice find on the injectors. I know they are stupid expensive new. What did you end up paying for them at the salvage yard?

Also, this shows some of my ignorance but why do you need to install a different oil pan for this?

 

[Robb235]

I don't know where I got the idea you said that, maybe this post?

Oh, yeah, that definitely should have read "and injects 30% less fuel than it normally would". I went back and edited. My fingers went a little faster than my brain as I was typing it up.

 

[Robb235]

Nice find on the injectors. I know they are stupid expensive new. What did you end up paying for them at the salvage yard?

I think I ended up paying right around $50.

Also, this shows some of my ignorance but why do you need to install a different oil pan for this?

Not a bad question at all. My 4Runner is my daily driver, so I didn't want to risk ruining my oil pan with it on the truck. So I bought a second one, had the bung welded on and ready to go, and then just swapped oil pans when I was ready. I actually sold my old oil pan to GioGuitarDude on the Tacoma forum and he did the same thing, lol.

 

[steezemcqueen]

I would strongly recommend you reconsider a intercooler

 

[rcrick]

I agree with recommending the intercooler. Even if you are convinced you don't need it at low boost, having a lower intake temp will help you make more power on less boost.

 

[IBallEngineer]

For example, let's say you increase the MAF tube by 30%. Now the ECU thinks the engine is inhaling 30% less air, and injects 30% less fuel than it normally would. Now add 30% larger injectors, and it brings you back to where you need to be.

In my case, the 315cc injectors are 31% larger than stock. To change the MAF tube from the stock 2.75" to 3" would be a change of 19%. The 31% increase from the injectors, minus the 19% increase MAF diameter still means that the computer would run 12% richer than expected, however, I feel that the ECU could adjust for that via the Long Term Fuel Trims.

Anyone follow what I'm saying? Comments? The only problem that I can see is that with the larger injectors and MAF tube, the computer would be calculating a lower load, and might advance timing. But how much (if any) I have no idea.

Or I could just leave the MAF tube alone (leave it at stock 2.75"), put on the 315cc injectors, and just start running E85, lol. Would need an upgraded fuel pump for E85. I'll probably need an upgraded fuel pump anyways though just for more fuel flow required by the turbo.

OK, I have read this a few times, trying to follow the logic. I like to believe this stuff is simple logic, but it does require understanding of the principles involved and maybe I'm not fully dialed in. Let me be clear though, this is NOT a criticism, it is an attempt to understand. Because its not making sense, to me.

Let's start with the following statement.

"For example, let's say you increase the MAF tube by 30%. Now the ECU thinks the engine is inhaling 30% less air, and injects 30% less fuel than it normally would. Now add 30% larger injectors, and it brings you back to where you need to be."

Are you saying that because the OEM MAF is calculating the air flow based on a specific tube diameter that it won't detect the additional air flow? Will it just assume the airflow is what it would be if the tube diameter was unchanged? I just can't get my head around that. Because the air flow isn't a static thing, it is dynamic and I'm sure there will be some changes, I just don't know what that would be. I'd want more explanation before I made changes.

Second thing is the math here.

"In my case, the 315cc injectors are 31% larger than stock. To change the MAF tube from the stock 2.75" to 3" would be a change of 19%. The 31% increase from the injectors, minus the 19% increase MAF diameter still means that the computer would run 12% richer than expected, however, I feel that the ECU could adjust for that via the Long Term Fuel Trims."

Using the formula Pi X r2.

Radius of 3 is 1.5
1.5 x 1.5 = 2.25
2.25 x 3.14 rounds up to 7.07

Radius of 2.75 is 1.375
1.375 x 1.375 =1.89
1.89 x 3.14 rounds up to 5.94

The difference is 1.13

1.13 divided by 7.07 is 0.159, or 16%

I know I'm splitting hairs, but if we are going to be scientific about your approach, lets do it right. Now your airflow, assuming we are correct, is only 1/2 what the fuel flow is increased.

OK, lets figure it out now. :loco:

Edit, wow thats some wierd azz shite going on with the colors I used.

 

[I-4x4]

.

Are you saying that because the OEM MAF is calculating the air flow based on a specific tube diameter that it won't detect the additional air flow? Will it just assume the airflow is what it would be if the tube diameter was unchanged? I just can't get my head around that. Because the air flow isn't a static thing, it is dynamic and I'm sure there will be some changes, I just don't know what that would be. I'd want more explanation before I made changes.

The way I read what he was saying is that the larger diameter tubing will decrease the air flow rate. In theory, the larger tube would cause the ECU to reduce the amount of fuel injected to match the reduction in air flow (even though the volume of air is higher).

It is like putting a nozzle on a garden hose - higher flow rate from reduced diameter - just backwards.

Good catch on the math btw.

What I want to know is how the rate of airflow is effected by pressuring the system to 7 psi? In theory, wouldn't it reduce the airflow by comparison to the naturally aspirated system?

 

[JayRolla]

Tricking the maf is not a good idea. If you go to far the ecu could still think its in closed loop and at WOT you will be on a very high timing curve which could cause lots of detonation. This is why piggy back EMS suck. People will run e85 to try and combat that super high timing curve. Just swapping a larger intake will not give the motor more air. It frees the flow to the motor but dont increase the airflow like you think. To do what your talking about in our DSM's we had to swap a larger maf in that would increase the airflow, not just the intake.

You need to swap the entire maf to a unit that takes in more air to get your logic correct. We would add a later model maf to our DSM's which would compensate for larger injectors. Also our maf can only do a little correction. IF you put larger injectors in and dont tune the fuel trims your ecu could be stuck at 120% fuel trim and you get no correction anymore. The larger intake is not like a turbo where just larger will get your increased air flow. Your best bet is a full tuning system to get full advantage.

Also you 57 trim at low boost wont be inefficient at higher rpms. Ive pushed 50 trims to 30psi on a smaller motor and it pulled all the way.

 

[0xfded]

I believe his reasoning is this:

Fundamentally, the engine is going to draw as much air as it is being asked to draw, and capable of drawing. When you say "higher RPM please", you're telling the engine to draw more air and expect the ECU to mix in the right amount of fuel.

The MAF detects airflow (and assumes a bore area of pi * 2.75^2= 23.76 square inches) and the ECU uses that to determine how much fuel to send (and assumes stock injectors.)

When he increases the injector size by 31%, he's increasing the fuel that the ECU injects (in response to the airflow it assumes is coming through a stock intake) by 31%.

That throws the AF ratio off, so he increases the diameter of the MAF bore to pi * 3^2= 28.27, which is 19% larger. But the MAF doesn't know the bore is larger, so when it sees air going by, it doesn't know 19% more is passing through than usual. So it tells the ECU "you're getting 1 unit of air" when it's really getting 1.19 units, and the ECU says "I'm injecting 1 unit of fuel" when really it's injecting 1.31. The ECU will then detect that it's burning a bit rich, assume something is odd (like a squirrel nest in the air filter box), and correct for it via fuel trim.

It's pretty clever. I have no idea if it's going to work, but I'm eagerly watching this thread to see. It's a pleasingly simple solution.