G1625S

I finally got around to drilling and tapping the manifold today. Once the turbo was off it took lest than 3 minutes from punching a start spot to cleaning the filings. I don't know if I got a real good drill bit or if cast iron is just that soft...anyway, here's my dilema: I drilled and tapped for 1/8'' NPT. My probe has 1/4'' NPT threads, so I bought a 1/8'' nipple and a 1/8''-1/4'' adapter. The problem is the probe is over 3'' long--it protruded almost all the way through the downpipe! To keep it from extending what I thought to be too far into the manifold, I had to space the probe back a fair bit. Now I've got, say, alomost 1/4'' of probe in the manifold. Is this enough? Is the longer probe meant to have more of its surface area exposed? The reason I'm asking is because my temps did not go up enough, IMO. Cruise @70mph was just about 600, @10psi. That seems low for a non-ic truck, though I am running lots of timing. I'll get some pics of the setup tomorrow to give a better idea of what I'm talking about. So there that is. Suggestions, comments, etc, etc?


Moving along...I thought I'd tear the divider out of the 12cm, but I just didn't have enough daylight to work with. Instead, I port matched the 12cm to the metal gasket. I'll be the first to say I'm no expert, but that casting leaves a LOT to be desired from an airflow standpoint! There was an easy 1/8'' of material before the gasket all the way around the housing. I marked the offending material with a sharpie and got to grinding and blending..and grinding and blending...and grinding and blending..and... I could have cast a couple powerstroke connecting rods with the pile of filings I had . Now personally, I don't consider the 12cm spooled untill it's over 12psi..it seems you've got 10psi just idling Anyway, from 10psi on, what a HUGE difference in the amount of fuel it takes to go from 10 to say, 25psi. Just the slightest tap sends the boost gauge (from 8-10psi) smoothly and quickly up to 20-25psi. Where before, I'd get a black puff and a surge, now there's no puff and the power increase is seamless and the truck feels like it runs 'easier', if that makes any sense. For what I did, I'm very pleased, but I do have some concern about my pyro probe. Are new ones pricey? I'd like to purchace one that is shorter ans set up for 1/8'' NPT. Mine's got two wires at the end of the lead, which is about 12 inches. The gauge is an older Isspro. Both wires go to the gauge, if that helps. Phew! It took longer to type all that then it did to do it
greg

DODGE 92

sounds like you had same prob as me probe is too long i bought an extender mine runs at 500 at 70 mph anyway its the end of the probe that counts

G1625S

Good to know I'm just so used to the post-turbo readings...I'm not sure what to expect. Plus, my backyard porting job may have cooled things off more than I thought. I hated to change two variables at once, but not as much as I'd hate taking the turbo off/apart two days in a row. Maybe I just need more fuel

Underpsi

My pyro reads about 750 at 75mph if that helps you with your readings

bgilbert

You want more in there. You want it right in the center of the stream. Is your probe adjustable? When you said you had to space it back a fair bit, can you just go less on the spacing? IMO, 1/4" is not near enough. Run it to the bottom, then back it off an inch or so.

G1625S

I bought three different length pipe nipples--a closed nipple (all threads, about 1/2'') a 1.5'' and a 2''. The 1.5'' is in there now. The 1/2'' put the probe tip about 1/4'' from the bottom of the manifold, but maybe I can thread it in a little less and lock the threads...I'll go have a look right now

wannadiesel

My truck ran cooler on the highway with the 12 cm, I don't think 600 degrees is out of range. Ideally the tip should be in the center of the runner. There's no adjustability in the probe? Except for AutoMeter, all the probes I've seen are in a compression fitting and you can put them wherever you want.


I'm glad you noticed a difference from porting. I already had POD's in the truck when I ported mine, and it went from too hot to still too hot. I couldn't stay on it long enough to tell if it made a real difference.

Did you drill out the divider or are you still only wastegating 3 cylinders?

Alec

It is probably a little late, but most of the probes that I have seen can be run through a regular old 1/4" compression fitting -- so you just buy a new ferrule (& fitting if needed) and adjust the protrusion however you want.

G1625S

Well, I adjusted my adapters so the probe is just about in the middle of the runner, give or take. The probe itself is pretty old--it very well could be a compression fitting, but the threads etc are pretty mangled, so I'm just making due. Not too worry, though, she gets plenty hot! I'm not used to the pyro moving so fast, or so far! The good news is that under moderate romping, it seems to plane out around 950 or so at 30psi. I haven't done an all out flog because I can't get past the mental block I have with 900 degrees, hehe. Maybe in a couple days. 'Course, in a couple days, my EDM's will be here

Dave: I drilled the divider the day I got the housing, but now that I've seen the difference a little cleanup can do, I'm tempted to hog the rest out

I also bought one of these from Bill:

I held it up next to the stock crossover and it absolutely dwarfed it, so the custom crossover will be coming sooner rather than later. Plus, I could probably adapt water/meth nozzles to the pluged ports on the horn

And yes, I have been digging around the web-smilie site

Go ahead, try it

Lil Dog

Thats exactly what I did with my Autometer kit on my 93 CTD. The probe was waaay too long and that made a difference adjusting it to the center of the stream.

You don't need alot of compression on that fitting to hold it.

wannadiesel

Only 950? You can get it hotter than that!

That is gonna be a fun ol' truck with the EDM's and water/meth.

G1625S

Thanks for all the advise on the probe. I'm gonna get a new compression nut tomorrow and give it a go