Inliners International Forums General Discussion Blown and Injected Max boost for 292?

What is the maximum boost you would consider pushing a 292 to that has arp studs and 1025 headgasket, no o-rings?

There is alot of questions to be asked to answer that question.

Is there going to be accurate timing control?
Compression ratio?
Fuel?
Quench?

ect, ect, ect

I bet 15-20 would be handled. Tom

Yes
9.8:1 (10:1 is like 8:1 on gas)
propane (105 octane)
.004 in the hole, pistons have a small dish. Quench is about as good as I could make it.

I would like to go like 25. Just thinking about something weird to get around the boost limit of my propane regulator. This is just whatif so bear with me. I was reading about a guy who was using a compound turbo setup on his mitsubishi to get the big power he needed but it would still spool like a stocker without nitrous or weird antilag crutches. I can only run 8-10# of boost with my propane regulator, and 15 with a "turbo" regulator. So I was thinking that if I put the mixer between the two turbos, I could go like 9# on the first turbo, then it would be 23# on the second I think. I believe you try for the same pressure ratio on both, which is what these numbers give you. I'm still reading up on this. Anyway, my current setup could be modified to a compound setup pretty easily - and if someone asked if I went blowthrough or drawthrough, my answer would be "yes". And I wouldn't need the nitrous to make the number I'm looking for. I would have to use the water/meth setup after the second turbo for intercooling, and probably an intercooler between the two stages before the mixer, although having my big turbo in the back like I do, the charge pipe is already a pretty effective intercooler. It would just end up with more boost than I've heard of running up here, and I don't know if I have the cajones of douglas, edy and those cats down south. I'm not saying it would be a practical setup or a better setup, just a different one (which isn't a plus necessarily, I know, but I'm weird) and I'm just wondering if it is possible, and how many heads would get scratched looking at it. This is mostly a theoretical exercise at this point. I guess I'm looking to get talked out of it. Or maybe into it? I don't know.

You are gustsy with the propane setup. I have easy access to it on my farm. Use it in the forklift, bbq grill and a truck at one time. So I am very familiar with it. But just can't quite figure out how to use it under boost.

I have researched using LPG injectors ( like EFI) They are expensive and hard to get.

School me on using it under boost. Tom

If you size the turbos correctly you can get more mass flow out of compunds for a given boost # than you can out of a single.

You almost never hear about that because most people with compund turbos are going for max power.

I've seen some of the diesel guys go compunds and pick up both power and economy due to the lower "drive pressure" (back pressure in the exhaust between the engine and turbos if you prefer).

They seem to go there for both the broader torque range (earlier spool without extra foolishness, like you say you want) and lower EGTs (more air in a street diesel = cooler EGTs as they run lean of peak, all the time).

Charge cooling before the mixer isn't a bad idea, as you definetly don't want it after the mixer. (yes I figure you already know that, but it bears saying)

The hard part will be sizing the turbos without spending a fortune.

An external wastegate for the high pressure turbo seems to help on the diesels as they tend to have the high pressure turbo's turbine turn into a choke point, to the extent the low pressure turbo can have a hard time spooling.

I like the JGS brand, but I would, they're made domestically, not at all like the $bay chi com stuff, so kinda pricey.

For whatever it's worth I've got a 3,9L (so ~ 239 CID) Diesel (Isuzu 4BD2-TC 3200 RPM redline) with a HY35W Holset single on it.

I have to put the injection pump back on (had it repaired) but the HY35 seems to spool somewhat late. It's the stock turbo off a Dodge Cummins, 5.9L, with that automatic from a certain year range. I wouldn't normally try that much larger a turbo, but the Hy was undersized for the 5.9 to keep the smoke down as the converter slipped in lower gears.

I've been looking at building a compound set for the diesel I have (see, a tie in, crazy aint it? ).

The two combos I have found discused (ie people have tried) are a HX30W Holset (smaller than what I have on there now) for high pressure, with a HX40 variant for the "low pressure" turbo (basically what Cummins, Cat, etc used on the 8+ liter engines, ala Kenworth, etc). That seems to be the prefered setup for a stock engine with an unmolested injection pump and stock injectors.

The other, that seems to be prefered by people with lighter vehicles, and modified engines / injection stuff is the HY35W or HE341 (very simliar size, '341 might spool a little quicker, and move more air as it's newer tech) over either a HX52 or a HX55 Holset. Both are huge and people seem to like them, when they want to make a 100-120 HP engine into a 300- 400 HP engine (I would be delighted to get 225-250 out of mine, it started at roughly 150, these are diesel #'s though).

So that wouldn't likely translate directly, as you have a somewhat larger engine (4.9L) and faster redline, but lower air requirement per HP (mine runs lean of 22:1 or I'm pouring fuel [black smoke] out the pipe).

The Holsets and Borg Warners (S200, S300, S400 series) are available as take offs, from people that are either upgrading or otherwise repowering, often for fairly cheap. It's why I posted all this, I thought you might want to know.

Hope some of it helps.

Tom, the propane setup is actually easier than carb or EFI, especially for blow-through.

Well, after extended research and discussion with people that have done this, I've decided not to. My reasons were 1) my mixer is only 460 cfm. While a touch on the big side for blowthrough, it would be too small to draw through the second turbo, which causes the mixer to lean out on top - and lean is only good when you're discussing calendar girls. 2) When you gas it, the little turbo spools immediately, kicking the big turbo in, and it's like a switch - which sounds awesome when you're thinking about eliminating lag, but not so awesome when you're picking up your kids from your ex who lives across the street from the police station or it's raining and you're pulling a hill. I'll stick with the less responsive single turbo, and use the nitrous to whack it at the track.

BTW Nexsussian in my research I found the powerplant for my future model A project - a 4bt with an HE351 over the stock 4bt turbo - makes 300hp and can be adapted to anything.

Theres a 4BT 30-31 sedan on the 4bt forum. Great looking hot rod. I have a 4BT in a 59 Willys wagon I've been building off and on for a couple of years. HX35, intercooled with bigger injectors. Should be fun. I picked the body up in Olalla which I think is in your neck of the woods.

A 351 should be large enough for a primary.

Which "stock" turbo does it have? (just curious).

Harry, yes, Crusty's ride is a heck of a nice piece.

Well,Cometic or the makers of Cometic is supposed to be making head gaskets for our 194-292 engines.
There suposed to be good for high boost pressures. Well see.
Approx $100.00


MBHD

Cometic gaskets are MLM (multi-layered metal matrix) gaskets. They require that the head and block faces be machined to very smooth surface finishes. If you were using composition gaskets (e.g. Felpro) and are going to switch to Cometic you will have to resurface your block and head to get a smooooth surface finish. Been there.