Opinions on engine

Ok, so as you probably know from my build thread, I just toasted another engine. I have yet to pop the pan and see what's up, but I still had oil pressure after it popped so I am assuming that like last time, the big end is intact and I either folded a rod, broke a piston, etc.

I know the general opinion is that a stock untouched l32 is the way to go. My concern is that I can, and fully intend to, lug this engine at very high boost and relatively low rpm compared to any previous high HP 3800 build. So while the L32 may stand up just fine to 800+up on the big end, I am thinking the compression stresses on the rods will be significantly higher if I am making the same top end power, but get a ridiculous torque curve from 2,000rpms. I would ultimately like to be able to run full compound up to like 3000rpms, probably making 50-60psi boost down low.

With that said, does anybody think I should build an engine around the 4340 rods, or just freshen up a stock replacement L32? I obviously demolished the L26 at relatively low power compared to what I am planning...is an L32 really going to hold up to twice the torture or more? I'm running out of buildable blocks so I can't just keep throwing stuff together and crossing my fingers. And if I do go with the built option, forged pistons as well? Opinions?

I guess I will be better able to make an informed decision when I find out what failed for sure...but wanted to find out what you guys think in general. Thanks!
 
50+ psi??????

Theoretically I can get at least 20 out of the supercharger, and 55psi out of the turbo (while staying within the red line of the turbo) for a theoretical max boost of 76psi down low. The turbo should fall off to like 35ish on the top end, again, if I'm not overspeeding the compressor to make more. Judging by the response so far, the turbo will have no problem spoiling to that boost at a very low rpm in twincharged configuration if I just let it.

Lots of boost at low RPMs isn't as ridiculous as it sounds...I mean the 20psi or so of supercharger boost is really very underwhelming as long as I keep the throttle position such that the car doesn't downshift. Yeah, it's a stupid amount of torque but anybody that's driven a turbo diesel truck can tell you that doesn't necessarily translate to ridiculous power. But it sure makes power delivery nice and linear.
 
what turbo are you using, my 67 maxed out at 26 psi when the waste gate stuck closed, and you will need to probably add some extra head bolts and oring the block to hold as much boost as your talking about

It's also a 67. But it's king of the 67s. Borg Warner EFR 9180. Yeah, I haven't had any head lift or coolant loss or issues so far with just head studs, but I was definitely concerned with that when the boost gets turned up. I mean I was only around 20psi on purpose, except for that one accidental 30+psi run.
 
Uh how are you going to get 50+ psi down low? let alone push that through the motor?

How much were you making when it blew? whp/tq?

Well you just asked a question that makes me want to do maths. So this will get long and ranty. Basically the answer is because with the smaller pulley on the TVS, it should make 20-25psi. Call it 23, that's a pressure ratio of 2.56, which gives me the exhaust gas volume of a 9.75L naturally aspirated motor, plus whatever extra volume I get from the water/meth...people claim it helps spool turbos, I am not convinced. But either way it will have no trouble spooling the turbo at 2000rpms, which will push 55psi if I let it.

But if we are talking theoretical boost to red line, most likely I would run 32psi or so, as that's what the current wastegate canister is rated to. Realistically, with the 2.5 pressure ratio of the supercharger at that point, 50psi would be a ridiculously conservative estimate if I left it in full compound...but that would be ridiculous and inefficient and pretty impossible to do from a knock, as well as a parts staying together standpoint. I mean correct me if I'm wrong but the actual math is basically
32psi turbo boost+14.7psi atmospheric pressure=46.7psi absolute in the SC inlet.
*2.5pressure ratio=116.75psi absolute in the manifold.
-14.7psi atmospheric pressure= 102.05psi of boost.

The charge heating would be obscene unless my post-turbo intercooler could get the air back to ambient. Plus, I know from my accidental full compound pull the other day that I get small amounts of KR at even 20psi going into the supercharger and being compounded. Also, the belt slip is a huge problem and makes it unrealistic to run the SC in the top half of the RPM range even if it wouldn't cause knock. On top of that, the sealing area of my supercharger is something like 10x12 plus maybe a 4x6 section by the bypass door...so let's say 144 square inches...Times 102psi=14,688 pounds of force trying to rip my supercharger off of my 1/2" adapter plate.I also think that could be an issue. So I really don't want to run full compound through the whole rpm range, but it would sure be great to see the full 55psi out of the turbo down low, and I'm confident that I can get that with my overdriven TVS.

As far as pushing it through the motor, well that's exactly what this thread is about. I want ideas, not just for the bottom end necessarily, but in general. I'm willing to keep breaking parts and engines and solving problems for the sake of this project, but in the background somewhere, I would like to be putting together a "permanent" engine for it over time...addressing all the weaknesses and problems I have found along the way. Yes, I realize I could just turn high rpms and less boost and probably be just fine. But that's just not interesting to me. I know I'm crazy and different, and that it gets expensive and frustrating doing my own thing, but I also learn a lot and have fun and make people go WTF? more often.

As far as how much I was making when it let loose, I am going to say approximately 500hp crank @ 20psi...and ridiculous amounts of torque down low. Cuz twincharged.
 

Turbocharged400sbc

3800 & 4T80E > ALL
TCG Premium
Jun 16, 2007
32,541
15,849
hangover park IL
the L32 was a late 04 production thing....sorta after all the old stock was gone, if its an 04 with a steel pan its an l67 or early L32, if its an aluminum its most likely an L32.

i say this since ive seen one steel pan motor with PM rods but all alum pan engines ive torn down have been PM rods.

keep the l67 rods/pistons, fuck the PM rods.

pm rods were a cost saving measure, no more benefits exist other than a closer near net balance.
while cap fretting isnt an issue with the L32 rods fractured cap, that same feature tells you why the rods are not desirable.

the good news is that the 04 l67's seem to have the same thermal barrier coating applied to the piston crowns as the L32's

if your going to pull it apart and such, match the rods and rebalance, otherwise go through the oil mods and toss it in
 
the L32 was a late 04 production thing....sorta after all the old stock was gone, if its an 04 with a steel pan its an l67 or early L32, if its an aluminum its most likely an L32.

i say this since ive seen one steel pan motor with PM rods but all alum pan engines ive torn down have been PM rods.

keep the l67 rods/pistons, fuck the PM rods.

pm rods were a cost saving measure, no more benefits exist other than a closer near net balance.
while cap fretting isnt an issue with the L32 rods fractured cap, that same feature tells you why the rods are not desirable.

the good news is that the 04 l67's seem to have the same thermal barrier coating applied to the piston crowns as the L32's

if your going to pull it apart and such, match the rods and rebalance, otherwise go through the oil mods and toss it in

Yep, that's what I've got. Coated pistons and cast rods. It was a steel pan. I guess we'll see how it does!
 
So I popped the pistons out to hone and check everything out. All of my 2nd rings were seized. The two cylinders that had a ton of water in them, of course had all the rings seized, but the 2nd ring was seized on every piston...just about as tightly into the groove as it could get. Had to more or less chisel them out of there. Got them all freed up/cleaned up and replaced all the 2nd rings with ones that I had ordered for the other pistons (which ended up being oversized, so were never used).

The wrist pins and tops of the rods were kind of nasty and rusted, so I did go ahead and swap to the L32 rods I've had laying around forever. The pistons that came with them are diamond racing, but they are oversized, AND not all exactly the same piston, which I thought was odd. But the rods are set up with the ARP bolts so that's a plus, I guess. So anyway, I am going to end up with the pistons that originally came in the motor with new 2nd rings, and L32 rods with ARP bolts. Those rods had like new bearings in them, so I will check tolerances but probably end up just using those. So all in all, this shortblock will cost me about $0 plus a bunch of parts I had laying around.

Will it last? No clue. If it blows up again relatively quickly I'll probably just give up on building junk out of junk and go buy a cheap L67 donor car that I can actually drive and check out and make sure the engine is in good shape and use that one. Hell, I can probably come up with a whole car cheaper than a salvage engine these days.
 
thats the only drawback i have on my burn victim pulls is figuring out if they used water and if it got inside

The NA engine I had (the one I just blew up) was the same way...It was a front end wreck, but they had already pulled the maf sensor and airbox and stuff and the hood was all smashed. There was some water in that engine as well, but not nearly to the extent of this one. It made very low compression for an NA engine (like 130), but GREAT compression after the hone even reusing the old rings, so I'm hoping this one does fine too.
 

Rent Free

TCG Elite Member
Jan 26, 2015
24,407
20,261
Nowheresville North Dakota
3800 are already cheap if i even thought for a second the engine would be trouble or need to be honed or whatever not a chance id use it.

good compression carry on shit compression possible water inside no thanks!!

glad i know where a stash of wrecked l32 impalas are sitting in a potato warehouse.... 6 engines sitting there just need to be pulled. ive already bought the only 2 l67s the guy had.

one i blew up being stupid on a 3.4 and no other mods like year after i got out of HS the other one is in my 97 gtp that got tboned sitting in the barn at my moms. that 97 gtp was perfect someone blew up the trans minty body and i bought it for 700 bucks and put the whole cradle engine and trans in from the wrecked car.

same dude has a red 4 door that was toasted maybe i should try jew that engine from him too for like 200 bucks all id use anyways is the short block......

he use to buy insurance wrecks and rebuild them 1st time i was in that warehouse i thought the walls are singing the holy grail to me. engines on racks transmissions on racks, doors all lined up, brand new sorta fit hoods and headlights in boxes.... was a very organized operation.

sorry im off in left field now. if i was at home id go pull them engines and ship them out for a decent price. id bet 600 would be doable to chi.

i was buying engines at 400 a crack. :rofl:
 
3800 are already cheap if i even thought for a second the engine would be trouble or need to be honed or whatever not a chance id use it.

good compression carry on shit compression possible water inside no thanks!!

glad i know where a stash of wrecked l32 impalas are sitting in a potato warehouse.... 6 engines sitting there just need to be pulled. ive already bought the only 2 l67s the guy had.

one i blew up being stupid on a 3.4 and no other mods like year after i got out of HS the other one is in my 97 gtp that got tboned sitting in the barn at my moms. that 97 gtp was perfect someone blew up the trans minty body and i bought it for 700 bucks and put the whole cradle engine and trans in from the wrecked car.

same dude has a red 4 door that was toasted maybe i should try jew that engine from him too for like 200 bucks all id use anyways is the short block......

he use to buy insurance wrecks and rebuild them 1st time i was in that warehouse i thought the walls are singing the holy grail to me. engines on racks transmissions on racks, doors all lined up, brand new sorta fit hoods and headlights in boxes.... was a very organized operation.

sorry im off in left field now. if i was at home id go pull them engines and ship them out for a decent price. id bet 600 would be doable to chi.

i was buying engines at 400 a crack. :rofl:

Shit, if I could buy engines for $400 I definitely wouldn't be building them. L32s in my area are $1,000-1,500 if you can even find them. L67s are $700-$1,000 with decent miles. You also can get a whole running parts car for less than that with a bad trans or something though, lol.

In any case, for my purposes I really don't give a crap if there's been water in it or if I contaminate the bearings to hell by honing with the crank in place. Chances are it won't last 1,000 miles due to some catastrophic mechanical failure, let alone the twenty thousand I might get from having all sorts of honing slurry all over the inside of my engine.

I mean it's essentially just a little time for me to freshen one up unless I run across some part that's just absolutely trashed (like the 2nd rings on this one)...in which case, it's good I tore it down anyway. Of course, I'll have about $250 in parts (water pump, head gaskets, head studs, valve stem seals, spark plugs, etc)...but if the last budget freshen up like this is any indication, I'll have as good as a zero-time engine compression wise. That's really not something you're going to get out of any junkyard engine, regardless of mileage.

I mean I have plenty of spare 3800s laying around, but most of them NA, and I already know those won't handle what I've got, so I would have to build them into L67s at least. Any way I look at it, I don't have something that I can just drop in and go (except for maybe the engine that is in the adapter plate regal right now).
 

twinv6gtp

Turbo enthusiast
Jul 27, 2014
837
4
I have not found the limits of the 1997-2003 L67s yet.
That's with a good tune and zero knock.
WIth knock all bets are off.

I have seen 7000rpm 34 psi of boost and some nitrous on top. Make the math... that's a lot of HP. That was for short runs.
Longer runs over 30 psi no problem.
 

10sec

I haz dat teddy bear smile.
TCG Premium
Jul 26, 2008
25,942
5,812
Which does bring me to a question... OP, why the hell are you trying to make so much power in the lower RPM range? It's useless power anyways :dunno: If cars with simple turbo kits can light up the tires at 70mph, why make more power?
 
Which does bring me to a question... OP, why the hell are you trying to make so much power in the lower RPM range? It's useless power anyways :dunno: If cars with simple turbo kits can light up the tires at 70mph, why make more power?

That is the real question, isn't it? No reason in particular, other than because I can, and it will look sick on a dyno chart. I agree, it is completely useless from a speed perspective for pretty much any purpose except for breaking parts. It will certainly not get me down the track faster than brake boosting turbo only. But it does, believe it or not, have much better street manners than just the turbo. It's a daily driving kind of thing, more than a max power kind of thing.

Keep in mind, I have that ridiculous 170mm throttle body now from Joker. 40% throttle may as well be full throttle. There is a very specific throttle position that keeps the turbo from coming on too fast, and that is significantly below the throttle position that it takes to have any decent kind of acceleration naturally aspirated (before the boost comes on). With the supercharger providing instant boost down low, I can accelerate at a comfortably quick clip at a lower fixed throttle position without accidentally smoking the tires when the turbo comes on and drastically changes my throttling requirements...and I do still have that instant tire-smoking power available should I feel the need to ruin somebody's day.

I realize when I'm talking about 50+psi down low that you would think that puts it well outside the realm of just cruising around, but it's surprisingly tame (at least the 25ish I have been running has been). The idea is actually to give me better/more predictable street manners by being able to prevent the downshift in the tune and accelerate in a higher gear without feeling like it's just creeping along.

So really to answer the question, I want to make power down low so that I can go slower :drums:
 
I have not found the limits of the 1997-2003 L67s yet.
That's with a good tune and zero knock.
WIth knock all bets are off.

I have seen 7000rpm 34 psi of boost and some nitrous on top. Make the math... that's a lot of HP. That was for short runs.
Longer runs over 30 psi no problem.

That's good to hear. The knock shouldn't be an issue with 2 (or 3) stage intercooling as well as direct port water/meth and E85 primary fuel. Although I did experience some when in full compound at higher RPMs, I don't think that will be the case down low with a lot greater relative water/meth injection rate. My case is definitely still a lot different (tons more weight, less engines, lol).f

What do you think you are making at 34psi? I mean that's got to be over 1000hp before the spray at that rpm. Just using the BW calculator I come up with 1077 and 808 lb-ft. As I understand it torque is essentially linear with boost pressure, independent of HP or rpm though (excepting VE differences from cams at various rpms), and is more representative of the compressive stresses on the rods. If I understand that correctly, a car that runs 55psi at 100 rpms is just as likely to destroy a rod under compression as one running 55psi at 10,000rpms. If I let it run 55psi, for example, that's 1264 lb-ft of torque...significantly more stressful on the rods than your 808 (granted the nitrous could be bumping that up significantly depending on how much and when you are spraying).

If I could hit something stupid like 75psi (albeit very briefly in full compound down low) that's 1,625 lb-ft of torque...almost twice the rod stress that you are seeing without nitrous. And at only 600hp at that point. Do you see why I'm a little worried? Now I have no idea if I would be able to hit that kind of boost that low...I haven't let it run that wild. But I know the supercharger alone can do 20 at idle if I choose to let it, and I intend to drop the pulley size again when it goes back together, so it will definitely be hitting very significant boost numbers when the turbo starts pressurizing the inlet.

I suppose the best course of action for me would be to get the turbo running max boost all by itself and THEN start playing around with compound/twincharged down low. That way I at least get the top end of my setup tuned/dialed in before I blow up another engine. I mean it's spooling pretty good on its own anyway.
 
How about dead hooking 29.5 inch 10 inch wide slicks in 2nd gear off for a 1.31 60 foot on a 3300lbs car .
34 psi of boost and Nos at 4000rpm. Thats a lot of torque.

How much nitrous is that? Like I said, the torque is roughly the same at X boost regardless of rpm...but if you're adding a fixed "HP" worth of nitrous, it affects the torque differently based on rpm.
 
This thread needs more MS Paint and humor. Basically, I want a dyno chart that looks like this:

Twincharged%20dyno_1.png


Instead of the typical turbo only dyno that looks like this:
Turbo%20dyno_1.png


Yes, the turbo spools so hard that it bends the rules of the dyno chart.
 
Old Thread: Hello . There have been no replies in this thread for 90 days.
Content in this thread may no longer be relevant. Consider starting a new thread to get fresh replies.

Thread Info