I have long term goals of a turbo 383 LT1 small block. I currently have a stock Lt1 on N20. I was planning on using a small shot of N20 to spool the turbo when I do get this setup. What I WANT to do is build a forged 383 AFR 220's, Miniram intake, TPIS monoblade, supporting fuel system, built to withstand boost with an N/A cam in it. I would run a relatively small shot (150) on this set up untill I can afford a turbo set up, which would be installed in maybe 1-2 race seasons. I would then swap out the cam for a more turbo friendly cam in there. Is this a realistic idea or am I asking for trouble running my set up this way?

 

Nothing really wrong with the idea of running a low compression mild duration engine for awhile with nitrous. You'll just be down a bit on hp/tq,, but the juice will take care of ya when you need it.

You could actually design your compression ratio to work fairly well with the smaller combustion chamber of a stock LT1 head and to work NA. Then when you step up to the AFR's order them with larger chambers to reduce your compression and woila, low compression for turbo on the same shortblock.

Question though, why would you need a miniram intake on an LT1?

Mike

 

Well, I've been searching around on the limitations of the LT1 intake, and the only answer I get is "It allready flows well"...not really a straight foreward answer. However, I do see people running the range of hp I am realistically aiming for (700-800 rwhp) are running some sort of after market intake. I don't want to fork over the money for a hogen, and I would like not to have to switch over to a TB adapted carb manifold. If an LTX intake can support the type of power I want, or if I can port it to, then I would be all for it, if not I figured on using a mini ram or a super ram intake.

As for running ported LT1 heads, are you would suggest I do this while running N/A plus juice then upgrading to AFRs when I decide to go FI?

 

Well, I haven't done any research lately on the latest Miniram design (3rd design now??), but back when the 1st and 2nd designs were still around I remember reading some comparisons. The general sensus then, was that the Miniram was not worth the extra money when compared to a well ported LT1/LT4 manifold. I think a good ported LT4 manifold can hang with a Miniram any day, and it won't have the air distribution problems. Like I said though, maybe TPIS has since resolved the distribution problems after all, third times a charm . And just for reference, there are several guys over 700rwhp with an LT1/LT4 style manifold out there. There are even a couple OVER 800rwhp. I REALLY don't think the manifold is the bottle neck.

If I were going to attempt what you want to do with the compression, I'd do this. Pick a piston with correct dish that will ultimately work best with the larger chamber'd AFR's. If it were me, I'd aim for 8.5:1 to 9:1 with the 76cc combustion chamber. Then, calc out your CR with the smaller 58cc ported LT1 heads, should put you over 10:1 or so which would be fine for a weekend warrior on spray and still have enough compression to support a decent sized cam. You can use Impalla SS head gasket (.029 compressed) with the LT1 heads, because it's the thinest made for an LT1. Then when you're ready to get serious with the boost, you're only a head/gasket swap away.

Mike

 

SleeperZ28 made over 1000 Rwhp with an LT4 intake.

 

Good, that saves me from forking over me money. Would it be worth it to get an LT4 over an LT1 if I plan to port it? Also, can anyone refer me to a good porter for the intake? Also, would it be better to wait to get it ported when I get the FI/AFRs so the intake matches the heads? I don't think the stock intake will have much trouble flowing a mild 383 with a 150 shot, so it should be good.