confab

I hope they're not silly, but I really don't have any way of knowing unless I ask someone.

1) Port matching. How do you determine which gasket to use? Are there like, oversize gaskets, or standard sizes or ideal shapes or what exactly? Because I try to read about this and people say things like: "Matched to the 1205 gasket"

Is that some kind of standard? Why?

2) DIY tuning.. Is there a particular order to follow for this? Like a checklist or an order of operations?

Say a person has a flash PCM, two O2's in the header collectors and a logger.. What do you do first? I assume it is idle related, but what would be the natural progression from the beginning of a successful tune to the end?

3) Powder coat is very smooth, hard and durable.. Would reworking and then powder coating the INSIDE of the plenum and runners be a cheap alternative to high end abrasive smoothing techniques like extrude hone?

cv67

I wouldnt pc the inside of any engine part..port matching is overrated, just a detail most list. It helps but isnt really a big improvement
1205 is a little bigger than stock (1204)

EH removes material from parts, mainly to improve airflow because ya cant get a grinder in there.

MatthewMiller

I think this link gives a pretty good overview of the process: http://www.lt1pcmtuning.com/tips/. If you have a 94/95 then you can use Tunercat for the calibrating and reflashing. If you have a 96, then you either need to use Jet DST for the same functions or swap in a 94/95 PCM.

confab

Thanks.. Both of you.

I'm kind of planning the next step on the car.. It is a 24x EFI coil on cylinder kit.. Mostly to get rid of the 85 only burnoff and problems with that. Also, it will let me swap an E transmission into it.

But the tune will be completely haywire. I'll just have to do it myself, which I would prefer anyway. Flash it too, for that matter.. Or at least do some of it just to get it to run, to take it to someone who can tune it.

But it sounds like something neat to learn. It is interesting and I think it is a shame C4 doesn't have a "Scan and Tune" section.. Because it probably needs one worse than any of the other sections due to the now arcane stuff it takes to tune a C4.

In case anyone is interested in something similar, or is planning an LS Swap, I got two books and both are good. First is theory and math heavy. Second is excellent detail on the various aspects of LS controls and gives part numbers and compatibility info, you name it.. It is excellent and the guy who started EFIC wrote it... So, he knows something about it.

Engine Management: Advanced Tuning

How to Use and Upgrade to GM Gen III LS-Series Powertrain Control Systems

Also, as I have been hoarding parts for this, I think I found an alternative to EFIC's billet 24X timing cover. (Which you will need if you plan on a roller cam at some point for the early SBC. The plastic modded Vortec cover won't cut it.)


This cover is heavy cast aluminum, is clearanced for the reluctor and would appear to fit and seal both Vortec and early SBC timing chests.. And it's cheaper.. So..

I have it here now and the quality seems to be very high.

MatthewMiller

Ahh, okay. Well you're really going deep, then!


Greg Banish knows his stuff! I'd recommend that book to anyone.

confab

Yeah, it seems like for all the trouble and expense to do anything with it at all, I may as well get the maximum advantage for my effort.

Kinda collecting parts and reading about it for the moment. Got a transmission set aside for it. Watching the U-Pull yards.

Next major SnapOn purchase will be a flash programmer.. (Which I have to buy anyway.. So, I may as well have some fun with it. )

Hot Rod Roy

In my opinion, "port matching" doesn't mean "enlarging to match your gaskets". Gaskets are designed to allow a little movement during installation, and may end up protruding into your port! I'd rather accomplish a smoother transition between the manifold and the head, ignoring the tiny gap that might remain if the gasket opening is a bit larger than the port opening. I do this by making a cardboard templet (cereal box thickness) to match the larger of the two sizes (usually the head). Fit the blank templet to the mounting bolt holes, bolt the templet in place, then use a ball pein hammer to tap around the edges of the port to leave a mark in the cardboard to indicate the edges of the port. Cut out these openings, then fit the templet to the other part.

drcook

There are some excellent reads on this site:

http://www.gearhead-efi.com/Fuel-Injection/forum.php