Questions about turboing a 4.0 OHV

I have a ‘98 Explorer Sport with the 160HP 4.0 OHV motor & 5R55E trans, and I’d like to get the engine to produce more power. Since there doesn’t seem to be any int/exh valves on the shelf anywhere for the OHV 4.0 other than 1.71/1.36, I don’t see any meaningful way to build power without FI.

I’d simply like it to be stronger in the 0-5,000 RPM range, with emphasis towards the lower end/midrange, since I really don’t even make a habit of letting it go above 4,000 RPM. I don’t want to put together something that demands forged pistons, better rod bolts, or a better trans right now (if ever).

The plan would be to retain stock manifolds, and weld up a y-pipe with the turbo somewhere under the hood. I’d then run the downpipe to connect to the catback. I understand running an oil line, upgrading injectors and getting a tune is necessary.

Questions: Can I get away with using something like a 16G with an internal wastegate & be reasonably close to my goals? I like the idea of a 6-8 PSI internal wastegate since its built in, no mess, no fuss, & seem to go for $5-600 new.

Draw through the MAF or blow through it?

Will I need to upgrade the fuel pump & FPR?

Have I missed anything?

 

[turbo cat]

boosting the 4.0 ohv is fun they are quite strong and hold up well. As for turbo sizing you may want to map out the compressor maps by using a turbo calculator. Your truck is a EEC V so you have SCT/Tweecer/sniper/moates to choose from when it comes down to tuning. A larger pump and injectors will also be necesary if you want it done right. using the stock manifolds will be fine. post up the pics as you go.

 

[377Z]

Thanks for the reply.

Based on 7 PSI & guessing a VE of 80%, I would need about 30-35 lb/min air at 5,000 RPM. I can live with the low side since I typically don't wind the crap out of it.

I looked around some more and based on displacement & RPM range I think a turbo off of a GN would suit the 4.0 pretty well (I haven't found a compressor map for a stock GN turbo yet). I have a line on a couple local good used ones for pretty good prices, and this is the route I will be going.

Fortunately I already have Moates stuff for this, but I'm not the best with this stuff so I may pay someone to do it. Either way that's a looong ways off, I don't even have the turbo in hand (should be picking it up this weekend).

It will be slow going since I'll typically only get a day per week to work on it, and it has to compete with the maintenance issues with my DD. My first choice of turbos (super clean with no endplay, runout, or smoke) does not come with the exhaust elbow & wastegate flapper, so I'll have to scrounge that up (preferred) or go external. I'll need to get an idea of what elbows I'll need to plumb up the exhaust; I really hope I won't have to resort to just t-boning stuff together, but I really need to get in there and have a look. I'll need to figure out where to get the oil supply, and where to plumb the return, too.

Anyways, I'll try to snap off a couple pics of at least the turbo and the truck on Saturday.

 

[turbo cat]

There is a guy here using a GN turbo on his 4.0 and he has pushed it to 18lbs of boost reliably. There is plenty of room on an exploder to route a crossover pipe.

 

[377Z]

Picked up the turbo Saturday. Great condition with no endplay/runout, but missing the stock exhaust elbow. Will need to scrounge one of those, but I finally have my snail.

Naturally the camera battery was dead, pics this weekend.

 

[turbo cat]

what turbo is it?

 

[377Z]

Its a GN turbo. Very clean and the price was right, but still need to scrounge a stock exhaust elbow & wastegate.

I snapped a couple pics but I can't seem to post them (don't know where to host).

 

[Dennis F]

Its a GN turbo. Very clean and the price was right, but still need to scrounge a stock exhaust elbow & wastegate.

I snapped a couple pics but I can't seem to post them (don't know where to host).

I use photobucket to host pictures and other media.

For the GN stuff, I believe I have a wastegate in the garage if you still need it and I would also look around GN forums. I use www.turbobuick.com for my needs. I know I do not have the elbow as I had to use it on my 6152 upgrade.

 

[377Z]

I use photobucket to host pictures and other media.

For the GN stuff, I believe I have a wastegate in the garage if you still need it and I would also look around GN forums. I use www.turbobuick.com for my needs. I know I do not have the elbow as I had to use it on my 6152 upgrade.

I'll look into photobucket; gotta do it from home though since its blocked at work.

I do need a wastegate and elbow; what would you let the wastegate go for? I actually got the turbo from a guy local to me through turbobuick.com, he suggested placing a post in the want ads for the elbow, I just haven't got around to it yet.

 

[377Z]

Here it is, sorry for the delay.

Here it is on top of the Pacific Green Ex Sport it will eventually be going on.

Edit: they don't show up for me, don't know why. Here is the url for the album:

http://s692.photobucket.com/albums/vv282/377Z/

 

[jordan1948]

I take it this thread has somewhat.......died I guess you could say. Anyways I have a question about putting a turbo on the 4.0. Is there any special computer conections or do you just have to modify your intake and exhaust. Just a noob trying to understand.

 

[l8psiExplorer]

Hello I am the guy that they are talking about that has the GN turbo on a ohv 4.0l with a 5 spd sport. here is some pic of my Turbo Explorer Sport

 

[Limited02]

377Z-To post the pictures, you need to put the cursor over the image, you'll see "IMG Code." Copy that link and just paste it into the reply box where you type. It should show up then. Good luck on your turbo project!!!

 

[slammed98z]

here is my turbo 4.0 not as clean as one posted above but works. 270k motor on 10 lbs daily driven...

My setup is stock manifolds swapped from drivers to passenger side, passengers to driver. custom y pipe infront of engine. gm-4 turbo. ebay fmic. yada yada yada. if you need any help with the whole thing just e-mail me.

 

[Limited02]

Slammed98Z-Do you have any track times? And didn't you have a different set of wheels a while back? Bullets or something?

 

[slammed98z]

Slammed98Z-Do you have any track times? And didn't you have a different set of wheels a while back? Bullets or something?

no track times yet.... gotta get a clutch and a tune.... nope its always had these wheels on it.

 

[377Z]

Sorry its been so long, the whole project is waiting for me to have the time & place to work. I don't have my own garage, the truck & all my tools are in storage 25 miles from my home. Hoping to have my own garage again in a year or so.

When I can finally get back to it, I will take a minimalist approach--manifolds in the current position, I plan to weld up my own y-pipe & downpipe, & hopefully be able to plumb up to the stock catback placement. Not sure if I will use an intercooler or not for the first go-round, I don't want to bite of (even more) that I can't chew. Software wise I have Moates stuff for the stock Ford EEC, hopefully I will be able to get away with that along with some higher flow fuel injectors & maybe an adjustable fuel pressure regulator.

Of course, before all that I will need to get a new EPC solenoid, rebuild the valvebody, adjust the bands, & some other misc. crap on the 5R55E, since I unfortunately don't have the M5R1.