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Formerly weebeastie
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Discussion Starter · #1 ·
I can't find any real info on the internet or DSO about anyone running a G25-550 or 660 on a D series or specifically a DOHC ZC as I have in the wago. Beytek has a Pulsar copy on a z6 in an EG, but he's in UK and I think its tuned on a Maxxecu.

Either way here's what I'm looking for. I love the characteristics of my current GT28RS. Yes, the old disco potato. I really does match a D series well for a street driven turbo car. However, my current turbo is starting to show its age a little. Nothing major, no smoke train, not even really dropping boost up top, just has some very minor shaft play and is sensitive to what oil I run in the car. Too thin, and it'll shoot one puff of smoke on start up. But full boost right off the line at lower RPM's is really amazing, especially on the streets. It pulls like a freight train. I mean, honestly I wouldn't mind keeping the disco potato, just have to get a new CHRA at some point before this one lays down on me. The thought for me would be to upgrade to the G25 setup so that my power potential goes up if/when I switch to e85. Right now the cap is right around 340 at the wheels at 18 psi. Which is a respectable number and has turned a lot of heads, but the G25 would take it up into the mid 400's with ease I believe, but looking for others who have experience with it.

In my reading I've found that the 550 version supposedly spools better, so that would be the only reason I would be looking at it.

I wouldn't be able to afford a real deal Garrett G25. Those things sell for $2k, and there's no way to justify spending that much to make 100 more whp on a street car, so I would be looking at the Pulsar brand. Thoughts? Anyone have experience with them?

Here's what I'd be looking at:

PULSAR G25-550 Billet Wheel Ball Bearing Turbo T25 & IWG Hsg 0.72 A/R Actuator | eBay

And yes, I chose the internal waste gate and the t25 housing because this would bolt right into place of my old gt28rs.
 

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Formerly weebeastie
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1,359 Posts
Discussion Starter · #3 ·
You can borrow some of my turbo lags :)

Thats a pretty sweet looking turbo, seems sound!

Is your current turbo's CHRA a ball bearing setup?
Yes, current turbo is genuine Garrett BB. Hate to take a step back towards a Chinesium turbo, but can't see shelling out the beans to get a real deal G25, and don't think what I have is rebuildable. Unless there are other, better options, that don't require me changing the world out to fit them. The G25 is alluring because it comes in a smaller package than my T28, bolts up to the manifold, and supposedly can make 200 more hp than the gt28rs, while still spooling just as fast. That's the allure of the disco potato. As the new Camaro SS found out tonight at a stoplight. The boost comes on quick. I can let off at 45 and have already handed him the check from gapplebee's because it spools so quickly and jumps ahead so well. So for that alone, I don't particularly want to change, but if my turbo is on the downward slope (I need to pull it and do some checking to see really what shape its in), and will need replacing, I would at least like to have a plan.
 

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Formerly weebeastie
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Discussion Starter · #5 ·
the price of that one you posted, you can buy a brand new potato lol.
Garrett GT2860RS Turbo aka 'Disco Potato'

T2/T25/T28 Kit - Product

Well now dang! So I could get a brand new real deal GT28RS to replace mine for about the same price as the Pulsar G25. Won't have the same power potential, but it's a street car so that isn't the end of the world. Hmm, things to think over. I mean its pretty fast now for a wago, and I don't get hung up on numbers. More on how it performs. Plus with cams, e85, and a really good tune, we could probably max that turbo out with ease


The rebuild kits are cool, but looks like they are for the journal bearing version.


Hmm. Things to think about now. Same power, or more power........... What potential issues will more power bring out? Start snapping axles, etc.? Hmm.

You can borrow some of my turbo lags :)
LOL, you can keep the turbo lags. Been there done that, and sure 6k and up was fun, and dare I say scary when all the boost pressures finally kicked in and the car tried to find both ditches..........lol

This was long ago in a friends b18 LS/VTEC with some Chinese turbo on it. My built N/A EF hatch would wear him out. He hated it. Especially once I did the F2D swap. That car was a ripper. Not wagon fast, but she would rip. Hurt the feelings of more than a few Subie's that thought is a B swap or turbo. F22a6 had the torque!
 

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93 Civic HB SI
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Well now dang! So I could get a brand new real deal GT28RS to replace mine for about the same price as the Pulsar G25. Won't have the same power potential, but it's a street car so that isn't the end of the world. Hmm, things to think over. I mean its pretty fast now for a wago, and I don't get hung up on numbers. More on how it performs. Plus with cams, e85, and a really good tune, we could probably max that turbo out with ease


The rebuild kits are cool, but looks like they are for the journal bearing version.


Hmm. Things to think about now. Same power, or more power........... What potential issues will more power bring out? Start snapping axles, etc.? Hmm.
I need to experience this beast for myself before more power haha.

Keep her fun and reliable :) I vote new potato!

Next week is supposed to be nice, wanna meet up some time mid week next week?

LOL, you can keep the turbo lags. Been there done that, and sure 6k and up was fun, and dare I say scary when all the boost pressures finally kicked in and the car tried to find both ditches..........lol

This was long ago in a friends b18 LS/VTEC with some Chinese turbo on it. My built N/A EF hatch would wear him out. He hated it. Especially once I did the F2D swap. That car was a ripper. Not wagon fast, but she would rip. Hurt the feelings of more than a few Subie's that thought is a B swap or turbo. F22a6 had the torque!
I need to add another 1K of RPM so when I shift I stop falling out of VTEC lol, might help the lag a bit. Redline is set to 7200, 8200 wouldnt be too bad, about as far as I would feel comfortable!

She's no show stopper below 3K and from a dig, but get above 35, and it rolls out haha.

Let me know if you have time to meet up this coming week! A half way point between my work and yours is only 15 mins!
 

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BATSLOMAN GIVES NO FUCKS.
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talk to gpop maybe get a complete rebuild for less than the price of new. hell, they rebuilt mine for less than $600. they may surprise you....might even know of a hybrid solution
 

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Formerly weebeastie
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Discussion Starter · #8 ·
So last night I was deep down the turbo rabbit hole. Came across a company called RAC Turbo that is selling turbo's out of Las Vegas. They have their own version of the G25-550 and several other turbos. So I contacted them today and found some interesting info. Their turbos aren't 100% Chinese like the Pulsar units and the guy here in the States (Ruben) actually disassembles the turbos and balances them in his shop, then checks all the clearances, reassembles them, tests them, and then sells them. So....... all that being said, I can get their R49-550 which is a g25-550, for less than a new disco potato or even the Pulsar chinesium g25-550.

So now I've got to do some real thinking. I'm thinking my turbo is cooking my oil a little bit. If I stay completely out of boost my oil pressure remains higher at idle, after a pull in boost the oil pressure at idle goes down quite a bit. Pressure is great otherwise hot or cold. Just don't want to do damage to my engine, which I feel will eventually happen if that is what's happening. Someone help me understand if excess shaft play or excess wear could correlate to increased oil temp/lower oil pressure at idle. Or think I'm on the wrong path with that thought process.
 
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So last night I was deep down the turbo rabbit hole. Came across a company called RAC Turbo that is selling turbo's out of Las Vegas. They have their own version of the G25-550 and several other turbos. So I contacted them today and found some interesting info. Their turbos aren't 100% Chinese like the Pulsar units and the guy here in the States (Ruben) actually disassembles the turbos and balances them in his shop, then checks all the clearances, reassembles them, tests them, and then sells them. So....... all that being said, I can get their R49-550 which is a g25-550, for less than a new disco potato or even the Pulsar chinesium g25-550.

So now I've got to do some real thinking. I'm thinking my turbo is cooking my oil a little bit. If I stay completely out of boost my oil pressure remains higher at idle, after a pull in boost the oil pressure at idle goes down quite a bit. Pressure is great otherwise hot or cold. Just don't want to do damage to my engine, which I feel will eventually happen if that is what's happening. Someone help me understand if excess shaft play or excess wear could correlate to increased oil temp/lower oil pressure at idle. Or think I'm on the wrong path with that thought process.
When you say "it lowers after a pull", how much?

What gauge/sender type are you using?

Have you thought of installing a manual gauge just for giggles to verify your pressure sender?
 

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Formerly weebeastie
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Discussion Starter · #10 ·
When you say "it lowers after a pull", how much?

What gauge/sender type are you using?

Have you thought of installing a manual gauge just for giggles to verify your pressure sender?
Only lowers at idle and only lowers 4-5 psi, but thats going from 12-14 psi down to 8psi, 6 is what it says if I came off the interstate.

I'm using an Autometer electric gauge

2-1/16

And yes, I was just thinking last night of plumbing up a mechanical gauge just to be sure of what I'm seeing on the electric gauge.


Any blip of throttle (even just 1200-1400 rpms) and its 25 psi and increases by 15-18 each 1k rpms and has 70 psi at WOT in boost, so there's not a lack of pressure in power, just seems like either my sender is heating up or the oil itself is heating up or? Again, if I stay out of boost it takes a lot longer before the low numbers show up.

Perhaps I should think about replacing the sender before replacing anything else. I have known those to go bad before. We all know the sinking feeling to look over at an oil pressure gauge and see any number less than 10. It's frightening.
 
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Formerly weebeastie
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Discussion Starter · #11 ·
So........

Did a little reading this morning, and found several other cars with the same gauge displaying the same issue. Reads perfectly fine when throttle applied and when in power, but low idle oil pressure. They were using the same digital Autometer gauge. I'm running a Defi boost gauge, maybe it's time to upgrade my oil pressure gauge to a Defi unit to match. Read 3 different threads with the same issue. Perfect pressure everywhere but at idle.

Hoping that the anxiety was the worst part of this issue lol. Just don't want to hurt a good running engine because I was stupid.

On the hunt for a Defi oil pressure gauge to match my boost gauge now. Maybe some old Subie guy will have one that didn't work out (thats how I got my boost gauge cheap lol). Dude was pissed he blew up his WRX so I lucked out and got a really nice brand new Defi boost gauge for cheap. Or maybe I just buy it new like I should. Maybe that's the best idea.
 

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What oil type are you running? And when was the last time you were in the bottom end?

Do you happen to remember what the bearing clearances were when you last assembled the engine?

Has the low idle oil pressure always been there, or has it just recently started creeping in?

I wouldn't personally stress too much on idle oil pressure when hot. As long as you know the pump was good at assembly, it should be moving the volume required to keep the crank and rods floating with no load.

I would seriously consider pulling the sending unit, and thread in a mechanical shop gauge and tape it to the windshield and go for a rip and see what idle oil pressure looks like that way before doing anything :)


HF tools, these are literally the same gauges from China that Matco and Snap On use in their $600+ sets. Very accurate, and only $40.

Thread in the hose to the sender fitting, route it up to the wiper cowl, connect the gauge and duct tape it to the windshield.
 

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Formerly weebeastie
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Discussion Starter · #13 ·
That's actually a really sweet looking engine/trans oil pressure gauge set up. The fittings might be cheaper/lower quality (maybe not), but it does actually look legit for $40. In a limited search I found 4 different users of the same gauge I have commenting/complaining of the same issue. Plenty of pressure in power, great increase in PSI as RPM increases, but low pressure showing at idle. Bottom end has max 5k miles on it. I'd have to dig to find the bearing clearance when it was assembled, but this gauge has always read a little low at idle, I've just started paying closer attention to it. Oil pump is a stock ZC P29 pump. Best of the D series pumps.


Hopefully it is just the gauge. Because I would expect hot oil to lose a few psi, its just the range in which it shows its losing those PSI is what spooked me.


However, the upgrade to a G25-550 is still interesting to me. Just if its not a necessity I could concentrate on other things at this point.
 
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