LT1-LT4 Modifications 1993-97 Gen II Small Block V8

Least restrictive LT1 induction?

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Old 02-15-2014, 09:15 PM
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12sec.. it is not the easiest conversion unless you are OK with modifying stuff to make it fit. Fitting it is not so much the issue, as making it fit AND look clean. I have a Glasstek 4" cowl hood, and I know others have used this hood with a lid. Some other cowl hoods have clearance.. some do not.The hood needs a little notching even still. The LS1 lid base needs to be shaved down so it sits lower on the rad support. It gets a lot harder if you don't have the hood, and want to keep your stock rad and AC.
Old 02-15-2014, 09:38 PM
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I have the stock radiator and a/c. I had to shave the lower air box/ radiator support do that it sat flush to the core support. It took about 10 minutes with a dremel and fitting. The main kicker is I run a VFN Sunoco wide bolt on hood. Mine was special made the same as BOLO's. It's made to clear the lid with no cutting to the hood. They don't charge any extra to have the hood made this way so if you want one you just need to ask. It was definitely worth the wait on the hood to make sure I didn't have to cut my core support, and it makes for a cleaner, more factory looking install.
Old 02-16-2014, 06:39 AM
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Far as cranking compression, a stock LT1 can crank 200psi a built one over 12:1 compression might crank 240psi or more cam plays a meaningful part. If you want to worry about it ask Lloyd for a ballpark number as he would know the complete specs on the cam not just the simple specs you posted.

My old 190cc setup cranked like 227psi and was 11.2 compression. Current setup cranks even higher.

Really though I think the CAI is the culprit here, if the HP had gone wonky instead of flatline I would look at valve float. If it had just been soft from the start I would be looking at compression and some other things.
Old 02-16-2014, 11:34 AM
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Oh it also struck me that "make power to 7400rpm" could begin to plateau by say 6700 peak by 7000 and just not begin to fall off hard by 7400. My experience is with hydraulic setup but I can tell you some of the fastest heads/cam setups peak about 64-6500 but still making great power at 7-7100rpm when the pcm stops working right.
Old 02-16-2014, 11:53 AM
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Thanks for the responses about the LS1 lid. If I can get ahold of a 96-97 WS6 air box, that should be much more simple to fit shouldn't it? Assuming a hood to properly clear it, of course.
Old 02-16-2014, 11:59 AM
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Cranking/compression pressure not only tells u condition of cyl(s) but if your cam is spec'd correctly for your dynamic c.r. keeping u out of detonation. The reverse cooled LT1 may be more tolerant with this and the old sbc thumb rules may not be as accurate for the LT1. But on the other hand if your receiving the beginning of detonation the PCM will retard timing allowing the eng to run but u would be losing power. Without retard for knock eng life would be shortened.

Compression test/press for your build would be good for u to know rather than rely on hearsay or someones else's guess. It only takes 'bout and hour to do.
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Old 02-16-2014, 12:02 PM
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Originally Posted by 96capricemgr
Far as cranking compression, a stock LT1 can crank 200psi a built one over 12:1 compression might crank 240psi or more cam plays a meaningful part. If you want to worry about it ask Lloyd for a ballpark number as he would know the complete specs on the cam not just the simple specs you posted.

My old 190cc setup cranked like 227psi and was 11.2 compression. Current setup cranks even higher.

Really though I think the CAI is the culprit here, if the HP had gone wonky instead of flatline I would look at valve float. If it had just been soft from the start I would be looking at compression and some other things.
I do have the full cam card, I'm just at work and don't have it handy. This is really the direction I'm leaning as well and will test it out during the nitrous dyno. Lloyd was specifically told the engine will run to factory PCM limit and set the valvetrain/top end for that. Not saying float is impossible, just unlikely. Same with the engine compression. It was built by the most reputable LT1 builder in the area. We may get down to compression testing, but it will be much more cumbersome than removing the cai. Easy stuff first. LOL

Last edited by 12sec97Z28; 02-16-2014 at 12:11 PM.
Old 02-16-2014, 12:05 PM
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Originally Posted by cardo0
Cranking/compression pressure not only tells u condition of cyl(s) but if your cam is spec'd correctly for your dynamic c.r. keeping u out of detonation. The reverse cooled LT1 may be more tolerant with this and the old sbc thumb rules may not be as accurate for the LT1. But on the other hand if your receiving the beginning of detonation the PCM will retard timing allowing the eng to run but u would be losing power. Without retard for knock eng life would be shortened.

Compression test/press for your build would be good for u to know rather than rely on hearsay or someones else's guess. It only takes 'bout and hour to do.
cardo
We were getting less than 1 degree of retard at WOT on 93 octane. Something like .6* if I recall correctly.
Old 02-16-2014, 01:02 PM
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I believe that would be less than 1 degree from what was previously mapped. No one really knows what your timing map should be until u test the engine. Every engine will have its own timing (advance) "map". But how much timing it could have with your pump gas octane without excessive detonation/pre-ignition is limited by your dynamic compression ratio and reflected in your cranking pressure.

cardo
Old 02-17-2014, 01:54 PM
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Past seeing the difference between air filter vs no air filter on the dyno, you may need something like a sheet metal intake to really open things up.

I'm not a NA solid roller, but my cam is a 244/254 .574 114 LSA and the blower really needed a lot of air to see some gains. I ended up doing a custom sheet metal intake, and was very happy with the results.

I'm guessing you wanted to stay away from the sheet metal intake because of the cost. If you know anyone who fabricates, it may not be as bad as you think. I would never drop the coin that some of the ones go for online $1k+. I'm not saying mine was cheap, but it wasn't that bad either.


Last edited by CALL911; 02-17-2014 at 02:00 PM.
Old 02-17-2014, 02:08 PM
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My 2 cents on this.

I had a Moroso (or Honker) CAI and a K&N CAI and I wanted to determine which one is better flowing. I tried both and monitored the pressure drop at the MAP sensor using datamaster and determined that the K&N has about 2KPA lesser drop compared to the Moroso at WOT. I would say that the much larger filter on the K&N CAI accounted for this. So IMO, the K&N flowed better. Is it worth ditching a Moroso and getting a K&N, no.

I then did a similar test with out a CAI installed without a CAI installed to see if the MAF had any restriction. So testing with the MAF on and then off, no change. The MAF poses no obvious restriction.

Same test with the elbow with no MAF or CAI installed. Big difference in pressure drop with the elbow pulled. SAo IMO, the 90 degree elbow poses a very significant restriction in the LT1 induction while the other components, not so much. I would guess that the flowing air in the elbow just gets "slowed" as it passes through hence the reason the LS1 straight should induction design works so much better.

I have an old thread somewhere speaking to these findings in much greater detail if your interested.
Old 02-20-2014, 08:59 AM
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I bought my car with a K&N intake. Not only did I not like the idea of the 90* bend before the TB, but I didn't like how the intake tube has a funky shape.

Here was my solution:




I have no data to say whether the new intake is an improvement or not. I just dl DataMaster and need to pick up a cable to be able to data log. I also have not gone WOT just in case it does flow that much better, I do not want to create a lean condition. I have plans to dyno tune the car soon though. That is a 4" to 3.5" coupler from TB to MAF, then the MAF, then 3.5" to 3.5" coupler to 3.5" exhaust pipe. MINIMAL hood bracing notching was required and a little flattening of at the top radius of the pipe...This fits under a stock 95 hood as well. It's the first prototype so it's not the prettiest but it seems to function lol.
Old 02-20-2014, 09:08 AM
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Custom sheet metal intake is now a 6061 elbow...?
Old 02-20-2014, 09:17 AM
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Originally Posted by Shownomercy
Custom sheet metal intake is now a 6061 elbow...?
How did you come up with that? I had it custom made from my buddy. The 6061 doesn't come close to fitting under the hood with the Super Vic intake.
Old 02-20-2014, 09:57 AM
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Originally Posted by CALL911
How did you come up with that? I had it custom made from my buddy. The 6061 doesn't come close to fitting under the hood with the Super Vic intake.
You said its a custom sheet metal intake, when in fact you have a cast super vic intake. You have a sheet metal elbow, not intake. Just saying.
Old 02-20-2014, 10:13 AM
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Originally Posted by Shownomercy
You said its a custom sheet metal intake, when in fact you have a cast super vic intake. You have a sheet metal elbow, not intake. Just saying.
This still does not explain why you were calling my custom metal elbow a 6061 elbow. But I get it. You are always up to debate the pointless semantics.

Old 02-20-2014, 10:29 AM
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Originally Posted by CALL911
This still does not explain why you were calling my custom metal elbow a 6061 elbow. But I get it. You are always up to debate the pointless semantics.

Is it not 6061...? Usually thats the common metal, 7075 is a little more pricey.

Pointless semantics is posting a blower motor to offer advice to a NA motor question.
Old 02-20-2014, 10:43 AM
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Hehehe
Old 02-20-2014, 10:11 PM
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Originally Posted by CALL911
This still does not explain why you were calling my custom metal elbow a 6061 elbow. But I get it. You are always up to debate the pointless semantics.


Yes, there are several lurkers here that have no helpful intentions. I just consider them as parasitic drag to enthusiasm for high performance. Debating with them is wasted effort. But I do enjoy telling them that.

cardo
Old 02-21-2014, 01:42 AM
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Let's try and keep on topic here gents.


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