GA16DET - set to go! Starting prep work...

Petrovich · Nov 7th, 2005, 10:12 PM

I've been convinced by Wes and others to go nuts on this one... so, a little update here...

- Scored myself a set of 450cc injectors by accident

Are these too large? Would I have issues with idle speed? I wonder if I can run a dual-injector setup, that is, don't fire the big ones until more fuel is needed. I think you can do that with MS, but I'm not really sure.
- Also, I have a core K26 turbo with good impellers, case, and everything but... cooked bearings, which need to be replaced. This came off of a 2-liter 931, and is placed on stock 931's with 170hp, as well as 924 Carrera GT's with 220. Rumored to be good even for 250+hp, 21psi max boost. this looks very sentra-friendly (in fact, I think one could mount it up to the stock header

it's a weird three-bolt kind), but! requires an external wastegate, and it's [gasp] OIL-COOLED. Any opinions - after I rebuild it, should I use this one, or donate it to my V6 probe-touting friend and shell out 800 for a nice GT 3-series?... I run synth oil, and will use an oil cooler, but who knows...
- My probe friend also started welding with his rig and results are impressive, so I can have pretty much any form of header/pipe/etc done if I need it, very soon.
- Compression/visual inspection confirmed that my current engine is in top shape despite 157k miles, as in, even comp and NO sludge (sparkling aluminum is all I see) so I decided to start right away instead of building a second engine first.
- I have some serious rust issues

Rear bottom, right behind and below the doors, is rusted through on both sides - on one it's just the top layer and it still holds, but on the other I managed to punch through one easily, and the second layer with a bit of work. Minor surface rust all over, and some big stuff (not through yet) developing at driver side strut tower. Strange enough, pristine behind the rear axle. Yet to remove front quarters to see what's going on there (judging by squeaks, a lot). I guess I'll have to spend this extra insurance money on foam, glass, epoxy, bondo, and POR15 instead of new winter tires

And a full tank of welding gas, too. Hopefully this will result in stiffer chassis in the very end.
- Speaking of foam, what are the best places to shoot foam into?... I'm getting the catalytic-set kind, hopefully something stiff. Any recomendations?
- I also have Megasquirt coming in the mail, we'll be putting it on the Porsche this weekend. I hope to learn a great deal from it... And get one for myself

- What's the SAFE redline on bone-stock GA16?...
That's about it for now, more later...

wildmanee · Nov 7th, 2005, 10:26 PM

Sounds really good, what engine management are you going to use?

Petrovich · Nov 7th, 2005, 10:37 PM

Quote:

Originally Posted by wildmane

Sounds really good, what engine management are you going to use?

Megasquirt II. This covers both electronic ignition and fuel injection.
Right now we have our guinea pig, 924 trubo, getting this setup - stock Jetronic system got clogged thanks to not-so-mechanically-inclined previous owner. We're going to run just the injection first, and convert ignition at a later point (we're the lucky bastards whose 924 ignition still works fine after all those years). I plan to do the same on sentra - keep the distributor there, and convert to electronic ignition once it's warm and sunny outside

We got our full setup - pump, injectors, donor fuel rail (will have to modify to make it work), ECU kit including all sensors but TPS (which is coming off of my old sentra's TB, btw

) and oxygen sensor (we'll use stock), for 450$ - not that bad at all. IMO, a better deal than JWT, although certainly requires a lot more work - but once you get good at tuning it, you can add mods and not have to spend more $$$ for reprogramming

I'll let you know this weekend about our progress with the Porsche, although most likely some parts won't arrive this week and it'll just be soldering and prep work.

**wes** · Nov 8th, 2005, 12:28 AM

Where are the 450's from? You might have issue with them unless they are top feed and you can make your own rail...

You confuse me with your posts. You ask if the injectors are too big yet you are using the MS which, if my understanding is correct, can control any size injector. Why is this an issue with the MS?

Also you have been told what has been proven to work turbo and injector wise, why are you trying to re-invent the wheel here?

A T3 GT series is insane overkill. A T25 or T28 from an OEM Nissan application are perfect and cheap. If you want to shell out the $ get a GT28R or RS.

Petrovich · Nov 8th, 2005, 01:41 AM

Quote:

Originally Posted by wes

Where are the 450's from? You might have issue with them unless they are top feed and you can make your own rail...

You confuse me with your posts. You ask if the injectors are too big yet you are using the MS which, if my understanding is correct, can control any size injector. Why is this an issue with the MS?

Also you have been told what has been proven to work turbo and injector wise, why are you trying to re-invent the wheel here?

A T3 GT series is insane overkill. A T25 or T28 from an OEM Nissan application are perfect and cheap. If you want to shell out the $ get a GT28R or RS.

The 450's are from Talons, they're top feed. I got these as a backup set for 924 and most likely we won't need them, so I'll stick them in my Sentra. I will make my own rail.
The reason why those concern me so much is because MS instructions warn against issues that arise with idle and low throttle when using injectors that are too big. I'm not sure about the detail, but it has something to do with precision of injector cycle length. According to MS's guide, I need to be pushing over 250hp to justify 450's

I'm thinking about using a dual-injector setup - stock for low power, and big guns for when the stock are, say, over 50% duty cycle.
Obviously it's not that big of an oversize, but I want to play safe here.
BTW, aren't you running 50lb'ers right now? How does it idle?...
As for GT, I was just talking out of my arse

I'll prolly settle for T25 unless tomorrow morning I'll find out that K26 bolts right onto the stock manifold

Petrovich · Nov 8th, 2005, 01:46 AM

As for reinventing the wheel... What's the point of making a GA16DET when I can drop in an SR20DET and live happily ever after just like everybody else and their brothers

If I come upon something bad, I'm sure I'll recover from humiliation, and my body will mark a bad path for the rest of us

OTOH, if I come upon something unusually good, then, score

myoung · Nov 8th, 2005, 05:23 AM

Quote:

Originally Posted by Petrovich

As for reinventing the wheel... What's the point of making a GA16DET when I can drop in an SR20DET and live happily ever after just like everybody else and their brothers

You can't just drop it in...

Get ready for a long parts list...

**wes** · Nov 8th, 2005, 09:13 AM

I run 50 lb injectors and the car idles like stock. That is the benefit of proper tuning. I am sure the MS can accomodate for that in some way shapre or form, but I have no experience with it.

Petrovich · Nov 8th, 2005, 09:26 AM

Quote:

Originally Posted by wes

I run 50 lb injectors and the car idles like stock. That is the benefit of proper tuning. I am sure the MS can accomodate for that in some way shapre or form, but I have no experience with it.

Ok, in this case, I won't sweat it and I'll just slip the 450's in there. They are a bit smaller than 50 pounders anyway.

- Looked at K26 together with the engine bay today. LOL! This is so conflicting, it's funny. On one hand, it bolts RIGHT IN. I mean, three-bolt exhaust collector flange... It's just the same as the one on the turbo, 100%. On the other hand... good luck fitting the compressor part in there

There are 3 possible orientations; one is 100% out because it interferes with the transmission and its mount, second one requires removing the A/C (which I'll do anyway, but it still doesn't guarantee a fit), and the third portrudes into the radiator so much that one would have to remove the A/C condenser and push the radiator all the way forward

I'll take a better look sometime later this week, I'm seriously considering the A/C removal option. The radiator push might work, too, but it'll be so much weird cutting and fitting it ain't funny.
Otherwise, I'll keep the thing for some crazy turbo beater project - you could invert the headers and have the turbo sticking out of your hood... dumping fumes right through the exhaust opening on the turbo

Petrovich · Nov 8th, 2005, 11:08 AM

After checking again, I decided against K26. Too hard to fit, will require manifold spacers, might as well just get a normal manifold and turbo to begin with. Which brings up a question...
- Any good place to get header-worthy mandrel bent pipes? Any good place to get mandrel bent pipes for the exhaust, too?

**wes** · Nov 8th, 2005, 12:35 PM

Quote:

Originally Posted by Petrovich

After checking again, I decided against K26. Too hard to fit, will require manifold spacers, might as well just get a normal manifold and turbo to begin with. Which brings up a question...
- Any good place to get header-worthy mandrel bent pipes? Any good place to get mandrel bent pipes for the exhaust, too?

I would not use mandrel bent mild steel for a turbo manifold. I would use weld el's or the existing weld el log manifold kit that JGS tools sells.

Petrovich · Nov 8th, 2005, 01:08 PM

Quote:

Originally Posted by wes

I would not use mandrel bent mild steel for a turbo manifold. I would use weld el's or the existing weld el log manifold kit that JGS tools sells.

What's weld el?...
924 people (who are left in the dust as far as aftermarket support goes) use stainless steel for their headers, good/bad idea?... I wouldn't see any issues except for it being rather hard to weld.

**wes** · Nov 8th, 2005, 02:37 PM

Quote:

Originally Posted by Petrovich

What's weld el?...
924 people (who are left in the dust as far as aftermarket support goes) use stainless steel for their headers, good/bad idea?... I wouldn't see any issues except for it being rather hard to weld.

Stainless is great as long as you use the right quality and thickness! Weld el's are basically steam pipes.

http://www.jgstools.com/turbo/index2.html

This place sells weld it yourself kits. Granted you can get the weld el's for much less through an industrial supply house.

Petrovich · Nov 8th, 2005, 02:58 PM

Quote:

Originally Posted by wes

Stainless is great as long as you use the right quality and thickness! Weld el's are basically steam pipes.

http://www.jgstools.com/turbo/index2.html

This place sells weld it yourself kits. Granted you can get the weld el's for much less through an industrial supply house.

Yup. 924's wastegate pipe is stainless from factory, and it's paper thin - no wonder ours broke off

Petrovich · Nov 15th, 2005, 11:28 AM

WOHOOO!!!! Got news that final megasquirt components have arrived today (as in, fuel rail and some sensors). Unfortunately, Porsche is the priority, but I'll have pretty much the same setup for the sentra, so it doesn't really make a difference, sooner or later I'll have a second set coming my way. I'll get some pics when I'll get off work.
Is it me or Walbro 255 is amazingly small? I can almost hide it in my fist, the thing is just ~4 inches long. BTW does it need a screen or a filter on the input side? If so, where would I get one? I presume one just mounts the pump as low in the fuel tank as possible, runs a hose up to the rest of the system, and it's a done deal, does that sound right?...