Hey DSM, sorry to hijack your thread again, I will have to adjust my valves soon. I was curious on your opinion. A range of acceptable clearances is given. I was wondering if I should go towards the tight end (for ever so slightly more lift?) the middle, or the loose end (to accommodate for the ptv clearance?) maybe I'm conceptualizing this wrong, but I would think the clearance between the valve an rocker arm would play a small role in the amount of lift I get from the same cam.

 

Hey DSM, sorry to hijack your thread again, I will have to adjust my valves soon. I was curious on your opinion. A range of acceptable clearances is given. I was wondering if I should go towards the tight end (for ever so slightly more lift?) the middle, or the loose end (to accommodate for the ptv clearance?) maybe I'm conceptualizing this wrong, but I would think the clearance between the valve an rocker arm would play a small role in the amount of lift I get from the same cam.

 

Oh no worries that is the whole point of this thread really!

You want to be looser on the exhaust side, and I would shoot for middle or on the tight side for the intake valves. I don't think you'll pull much lift through the valve adjustment.

Too tight on either side hurts their ability to seat properly on the quench area and cool off, or even have issues sealing.

Too tight especially on the exhaust side can lead to melted valves. Since you are boosted, and higher cylinder pressure all else being the same means more heat!

Too loose on either obviously leaves you down on power if not having issues starting or stalling out in addition to some annoying ticking

 

I have about 25 pics I wanted to post and a bunch of stuff to go with them but the post was deleted somehow so I'll try again tomorrow lol

 

Just sitting them side by side looking at the compressor end of the two turbos, they look almost the same size. The housings are nearly identical.


But, on closer inspection a keen eye will see that the inlet side of the compressor wheel is significantly smaller on the GT25R, about 2mm actually (42.0mm):


14B Compressor Inducer (44.x mm):


Even with a penny for reference, the difference can be deceiving. The "mouth" of the GT25 gradually slopes inward forming a sort of bell shape shrinking on the way in towards the blades, where the 14B is just a straight bore on the way in.

That may not look like much but when comparing compressor side only that shows that the absolute flow flow for the GT25 is choked out much sooner than the 14B.

What really limits a compressor is actually the amount the exhaust or turbine side is able to discharge efficiently, and the difference is much more dramatic on the turbine side:


Turbine inlet side, TDO5H (6cm2) vs. T3:


GT25 turbine exducer is 53mm (exhaust outlet):


14B turbine exducer is 56mm, this is a BIG difference:


So the 14B will be more efficient (more boost on pump gas) and will make more power per psi boost. It will also move enough air on both the compressor and turbine side that it will hold full boost to redline, instead of tapering off the way the GT25s do when you start running double digit boost. This is because it doesn't choke the engine by allowing more flow. So it may spool a few hundred slower, but it will make more whp at the same boost level, and allows for much more power on the top end.

Where I would be lucky to get 250whp running the GT25 off it's published map (<55% efficiency) in terms of boost (17) and flow, the 14B can support enough air flow for north of 330whp @ 22-23psi and is still on the map in the 60% efficiency range!

This is still as efficient as many superchargers, but will create far more torque across a far wider rev-range.

 

You know the Rotrex that is used for 5PSI boost on the manual transmission GDs is the same that is used on the 10PSI kit minus a beautifully machined and finished restriction fitting .... I still haven't done a thing to my car due to aches and pains... Seasonal changes mess me up and it is hard to maintain my focus whether I am medicated or not... I need more space or I may have to put the W/M injector in the throttle body side of the I/C which would need to have a bung welded into place due to the thin aluminum... The I/C mounts directly to the throttle body so it may be possible to put the injector in the pipe if I trim the hose back some where the two connect..... I think I mentioned the two 7" cooling fans I picked up... Since I need to redirect the air flow coming through the radiator that is going up through the bottom of the I/C, I am going to do a box with one of the fans mounted on the side facing the center of the engine compartment with a manual switch like you suggested... I think I have had enough bourbon, Irish cream and coffee to get a little done so I will be off to the barn to see what kind of mess of things I can make.

 

One of the big issues with the GT25 turbo's is the design of the turbine side.

Two major flaws exist:

1.) Wastegate hole is too small, even on our tiny 1.5L engines the amount of exhaust gas that needs to by-pass is significant, and to do so efficiently the hole needs to be bored. The turbo isn't very efficient at boost levels over 15-16psi so I don't understand why a company like Honeywell-Garrett would over look that.

2.) The wastegate and turbine discharge are not segregated from each other. To make matters worse the 5 bolt downpipe has the turbine discharge centered in front of the exhaust opening making the least path of resistance through the turbine, and there is a ledge between the wastegate and the turbine which creates considerable turbulence for the gasses exiting the wastegate.

These two flaws, and they are significant, encourage boost creep and high backpressure. This in turn means less power can be made per psi, because more energy is wasted trying to evacuate the exhaust through the bottleneck, this also hurts spool which directly effects torque production. It also makes the turbo less pump gas-friendly.

Some pictures to illustrate this:


GT25 wastegate hole:


GT25 downpipe:


14B wastegate hole:


14B downpipe:




The 14B discharge seperates the discharge from the turbine and the wastegate allowing them to join later in the exhaust and gives chance for the flow to smooth out. This decreases backpressure, allowing more exhaust gas flow through the same size pipe. This makes the turbo more efficient on pump gas, makes for better boost control (far less likely to creep) and allows it to spool faster.




One way to enhance this even further is the wastegate dump. This basically lets your existing exhaust act like a bigger pipe. This is because all the exhaust gasses that go through the wastegate now get to leave the system and don't clog up the pipe, allowing the turbine to do its just unhindered, which again results in greater efficiency, less back pressure and quicker spool.



I picked up 500rpm and a good deal of torque at the same boost level on my DSM doing this with the 14B. I was also able to run more timing and boost overall after this mod because it allowed the system to breathe so much more freely.

It is loud though, and at night anyone behind me can see a foot and a half of flame scorching the road under me at full boost when the gate opens! The higher your boost though, the less you are bypassing with the wastegate, so it may not be necessary depending on your setup, but it can be a nice tweak even if you don't absolutely need it.

But again, it is very loud as it is basically letting the exhaust out only ~20" after leaving the engine.

 

There are bulkhead fittings that should let you mount the nozzle in a coupler hose if need be, but a solid mount on the IC outlet pipe would be ideal.

Just as long as it is after the IAT sensor!

Let me know how it goes! You have my cell number in a PM from a couple weeks ago if you have a question and my responses here are too slow

 

Just a quick update:

 

Are you going to get the Boom Slang harness?

 

Yes sir. I want to make this as clean and convenient as possible! Unlike the DSM, I don't feel like screwing with the main ECU connectors if I can avoid it.

Spent 30 minutes folded up in the DSM the other day re-wiring and pinning an ECU connector for the Wideband for Narrowband Simulation and datalogging the WB signal on the FrontO2 input (Pin 4) and the Knock sensor (Pin 9)



My Sciatica didn't like that so I am paying for it the last few days

 

Sciatica is jumping from one side to the other right now just like it always does this time of the year.. You might get an inversion table if you don't have one already... My doctors tell me to take it easy on it but in time I hope to be doing dumb bell exercises while inverted again..... When I finally get things I am already set to do accomplished I very well may have to get up there in your neck of the woods to set things up on my F/IC I know that you will be having a ball in your Fit pretty soon... Don't get too radical with the tune until you have an extra engine built for the radical stuff... why am I giggling while thinking about this silliness?

 

Yikes, I only have it down my right leg and up through my lower back. I don't have an inversion table, but have been using a 75cm yoga ball on my PT's recommendation.

I should get a table though.. You know of any that can handle ~300lbs?

I would love to help! Have you got to play with spraying a dab of water on things? Or still scheming?

As for the FIC, I am actually going to try and wring out as much power as possible while I am still N/A just to see what we can do on the completely stock setup with some proper plugs, Panson's Race ETC and some real fuel.

Funny you mention that though, I am planning on getting a second running longblock to build up and max out the 14B! I am sitting here grinning in anticipation myself!

 

Id be screwed without morphine, tramadol and other assorted anti inflation drugs and muscle relaxers.. But I guess I am still screwed with the pills since they don't do much good for my mental state I think the table I have is rated for 250lbs but I can't find where it says it is... I think I told you I picked up a couple of 7" 80W curved bladed fans. One is going under the intercooler to pull air through it and some warm air exiting the hood louvers may be entering the scoop so I might have to do something about that.. Maybe some duct tape over the bottom of the ones on the same side of the hood as the scoop will help some... The injector has a L shape fitting and I think I can use a straight one and not have a problem drilling and mounting it in the pipe to intercooler pipe to the throttle body if the L shaped one can't be made to fit... Well I can feel the effects of my meds and should be crawling into bed if I am to get anything done tomorrow.. I hope you can get some N/A power with the F/IC, that would really be great if you can... G'night.

 

I see you got the controller, did you start tuning yet?

 

Hi all,
I'm thinking of tuning my NA and, AFAIK AF ratios to look for would be:
- 14.7 @idle (but I've read that a slightly leaner one would be possible, at emission cost).
- around 13.5 at WOT.

Now, what about the interpolation? One could think of a line, or perhaps better a curve, but which would be the safe curvature maximizing power/economy?

Any hint would be welcome! , TIA,

 

I was going through my library and found this Compressor Maps. With the links it explains a turbo and tuning.

 

Not just yet I still need a harness, the one I am selling is for the A/T GD's and to save my back and make for a clean look I intent to spring for the Boomslang PNP harness.

Most of my time has been spent on the Laser but I am trying to do a few things differently. The setup is changing once more!

After the DSM is sorted out I only need to find injectors, a wideband O2 and that harness before the Fit goes under the knife! I took it out of storage to find I have developed a small but persistent oil drip from the turbo feed line and one of the return flanges and it has made a mess of part of my driveway.

I changed my plans on using ethanol because it has been so inconvenient around here, so I no longer need the 1450cc injectors either. I am actually downgrading to a set of 850's which can still deal with ~67lbs/min airflow using gas with IDC's in the high 80's at the AFRs I run.

And since the only time I will be pushing that much air, I'll be on a toluene blend, and the meth is yet another fuel injected seperately so I won't even be maxing out the 850s.

It certainly doesnt hurt that at ~82psi they flow far more than 850cc/min (43.5psi BFP + 37-38psi boost).



The goal is to get some part throttle quirks sorted out. My original 19year old wiring doesn't seem to be delivering ideal voltage at the injectors (+14v)

Same reason I decided I no longer need the 5Bar MAP. Simply because it doesn't have the resolution I am looking for on a 5volt input, so I am stepping down to a 4Bar sensor. I don't see myself running more than 41-42psi boost, so [-29.4inHg Vac - 44.1psi Boost] 4bar sensor should be a perfect match.

 

That will depend on fuel and compression.. you are on an 1.2L i-DSI?

If you want to give me your email, I can send you my Load v. RPM fuel and timing tables in the race car. So you can use that as a template. Only the the 1.0 and lower load section (y-axis) applies to you unless you are boosted. In which case it goes out to 2.4Bar, even though I boost beyond that it just uses those as the finals values so they are pretty conservative once you get up there.

I have a couple tunes saved, I will send you the less aggressive tables.

It will require you downloading ECMTuning freeware to view the DA tables. They are .eda which nothing else will open, just like .cal AEM files.

 

I knew you wanted to play with the stock tune first NA. Your parts are coming together and looking really nice. I forgot you need a wide band but the stock O2 has some adjustment because its a semi wide band and goes up to 1.250 volts compared to 1 volt narrow band.