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C4 Tech/Performance L98 Corvette and LT1 Corvette Technical Info, Internal Engine, External Engine

Improving the L98

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Old 05-06-2018, 02:19 AM
  #41  
confab
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Serious question.. Aren't we talking apples and oranges here?

The carb and intake setup is passing atomized fuel and air..

It's a different world.
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Old 05-06-2018, 02:23 AM
  #42  
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What is "dual plane" in a world of computerized engine management and port injection?
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Old 05-06-2018, 03:12 AM
  #43  
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Originally Posted by confab View Post
Serious question.. Aren't we talking apples and oranges here?

The carb and intake setup is passing atomized fuel and air..
So what? What's that got to do with anything? You're claiming the dual plane is a good solution for MPFI. It's not. it's a good solution for a CARB, because it fixes problems for carbed vehicles that a single plane can't. And EFI engine doesn't have those problems, doesn't need a dual plane...and that is why you never see a dual plane on a MPFI engine. The intake, while helpful and effective for a carb, isn't ideal for a MPFI engine.



Originally Posted by confab View Post
What is "dual plane" in a world of computerized engine management and port injection?
IDK what you're asking. It's a dual plane. Whether it be carb'ed or port injected...it's still:
has two planes, 4 even firing cylinders/plenum, and 180˚ intake events in each plenum.
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Old 05-06-2018, 03:26 PM
  #44  
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Originally Posted by Space387 View Post
With the response I am seeing it sounds like the best option will be to go for an LT style intake and a good healthy cam.
Or...a FFI intake/cam
Or...a SR intake/cam

Back in "the day", Lingenfelter chose the later.

Headers would help too. Will be hard to stay under $2k. It's been well communicated that the L98 has several obstacles (design features) specific to it's acceleration profile...that need "upgrade" for a different, more modern approach.

Edit: I missed pages 2-3 before reply above. It's still valid though I should have included the newer Edelbrock intake. Tuning will cost money when you are done...so don't forget that. As for the question about the difference in cam specs, you'd be better off going bigger than a stock LT1 cam for an upgrade...especially if you considered another intake beside the miniram.

The LT cam is a little better. The heads are too. Little improvements here/there add up....in addition to the inherent differences in the intakes. If you are comparing 3.73's vs 3.33, is probably, most likely, almost definitely the biggest difference you can feel in "street torque".

Last edited by GREGGPENN; 05-06-2018 at 06:09 PM.
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Old 05-06-2018, 05:27 PM
  #45  
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Originally Posted by GREGGPENN View Post
Or...a FFI intake/cam
Or...a SR intake/cam

Back in "the day", Lingenfelter chose the later.

Headers would help too. Will be hard to stay under $2k. It's been well communicated that the L98 has several obstacles (design features) specific to it's acceleration profile...that need "upgrade" for a different, more modern approach.
If he makes it $3000, we can have a good intake, headers and enough for misc stuff with room for growth should he want to make even more power or decide to part the car out and the parts will be more desirable.
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Old 05-06-2018, 07:26 PM
  #46  
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Hmmm, here's a dual plane intake for the LS3 motors from GM with the injector bosses cast in:https://www.gmperformancemotor.com/parts/19244037.html

And Dodge is in on it to with a dual plane EFI for their hemi: http://ocperformanceparts.com/the_1s...emi_dual_plane

And I know there a EFI dual plane for Buicks out there to.


Like GEN I Chevy can't use this????

The science speaks for it's self. Use it or lose it. Keep calling tunnel rams single planes just because they share a single plenum then why is there a need for a huge plenum on a tunnel ram? Why not just cut those plenums down? Because you would lose power big time thats why. Its a different animal and if you can't see that it your own problem. Keep calling a tunnel ram a single plane all you want but I won't.
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Old 05-06-2018, 08:03 PM
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Dude....ya don't "Get it". The size of the plenum doesn't change whether an intake is a dual plane or single. Let's read that again: The size of the plenum doesn't change whether an intake is a dual plane or single. A "Tunnel ram" is just one type of single plane intake.

Those intakes are for CARBs. CARBs. Do you realize why a CARB'ed engine benefits from a dual plane intake...but it doesn't matter with MPFI?

Do you realize that MPFI engines is what we're talking about in this thread?

No Engine Masters comps are being won with MPFI engines using dual plane intakes. The "Science speaks for itself".

You need to know what the "science" is though, in order to effectively throw down the "science" trump card. It helps too, if you understand the definitions of things.


.

Last edited by Tom400CFI; 05-06-2018 at 08:06 PM.
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Old 05-06-2018, 08:38 PM
  #48  
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I would leave the motor alone, do maintenance to it but dont spend money on it. It isn't worth any $$$ going into an old engine like that.

save up for the LS swap.

In the mean time use nitrous to get whatever power you want from it. Setup a progressive shot and install it well so that the next motor can also use it.
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Old 05-06-2018, 10:27 PM
  #49  
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Originally Posted by Tom400CFI View Post
I have all kinds of suggestions for intakes....but how handy are you?

I think and LT1 intake is great, cheap, pretty easy.

Miniram is the same effect but way easier, but more money

HSR has proven to be a winner, but won't fit 'Vette hood w/o mods.

My favorite "C4" intake in the world is the SLP T-Ram intake....direct bolt on, but $$$$....IF you can even find one.

I like different, so I'm always looking for T-ram's for sale. Also, there are some really cool Marine intakes that would work great, look different/unique, that I look at occasionally.

All depends on what suits you, your ideas and your abilities, the best.
Originally Posted by Tom400CFI View Post
Dude....ya don't "Get it". The size of the plenum doesn't change whether an intake is a dual plane or single. Let's read that again: The size of the plenum doesn't change whether an intake is a dual plane or single. A "Tunnel ram" is just one type of single plane intake.

Those intakes are for CARBs. CARBs. Do you realize why a CARB'ed engine benefits from a dual plane intake...but it doesn't matter with MPFI?

Do you realize that MPFI engines is what we're talking about in this thread?

No Engine Masters comps are being won with MPFI engines using dual plane intakes. The "Science speaks for itself".

You need to know what the "science" is though, in order to effectively throw down the "science" trump card. It helps too, if you understand the definitions of things.
.

So by your definition then your favorite intake is a SLP T-Ram which is a dual plane intake.. Yes your favorite intake separates each bank of cylinders and should be considered a dual plane intake. Well I do get it dude and it's called hypocrisy.. And it puts the Lingenfelter Super Ram somewhere in between depending on what someone considers the plenum for each bank inside the SR.

Have ever used the T-Ram? Does it even work or are the long flow paths to restrictive?? Why did it flop out of the market so fast? IMHO your favorite intake is a dual plane and was the biggest TPI flop.
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Old 05-06-2018, 11:14 PM
  #50  
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Originally Posted by cardo0 View Post
So by your definition then your favorite intake is a SLP T-Ram which is a dual plane intake.. Yes your favorite intake separates each bank of cylinders and should be considered a dual plane intake. Well I do get it dude and it's called hypocrisy.. And it puts the Lingenfelter Super Ram somewhere in between depending on what someone considers the plenum for each bank inside the SR.

Have ever used the T-Ram? Does it even work or are the long flow paths to restrictive?? Why did it flop out of the market so fast? IMHO your favorite intake is a dual plane and was the biggest TPI flop.
Multiple times in this thread, you come to battle with dead wrong info...try to "slam dunk" your point...which is wrong. I correct you...so you try again, using a different point/tactic, whatever...and you're totally wrong, again.

*The T-Ram is most definitely NOT a dual plane intake. Look up the definition of a dual plane intake, then look at the T-Ram. Does the T-Ram draw from the Plenum every 180˚ of crank rotation? No -it does so every 90˚. Are the pulses from each bank drawing on the plenum evenly? No -they're syncopated on each side. Are/is the plenum physically separated into two, isolated sides? No -it's open throughout. Are they/it on two different planes? No -same plane, same level, same chamber. Nope...that is not a dual plane intake. Definitions and knowledge of how stuff works, helps.

*The T-Ram most definitely does NOT separate each bank of cylinders. All 8 cylinders most definitely DO draw from the same "box", the same TB...same same. Now, the "box" is a bit convoluted and spread out -so I can see how that would stump someone like yourself....but functionally it's just a big box, as far as what the runners "see", and how it functions.

*The T-Ram's runners are NOT "to (sic) long". They're shorter than the TPI and as a consequence, it raises the RPM range, some. Remember, the OP had asked about increasing low RPM TQ.
"Does the T-Ram even work?" How can you ask a question about something that you obviously are an expert on...right? You seem to know aaaaall about the T-Ram...Right? Wrong. You DON'T "get it". You're totally wrong and everything you think you know about the T-Ram is wrong.

The T-Ram works. It made 350 NET hp/390 tq with 350 CID, through 113 heads, on pump gas and passed emissions (OEM emissions -not what we have to pass). This was in '92 when a LT5 was getting 400 hp with 4 cams and 32 valves, and Viper was getting 450 hp with 488 CID or so. So...yeah, the T-Ram works. It's a fantastic, single plane MPFI intake. You should learn about it.

FF to 1:00. No major point here...just a vid showing how well that engine worked. It worked.

.

Last edited by Tom400CFI; 05-12-2018 at 03:17 PM.
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Old 05-07-2018, 12:48 AM
  #51  
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Originally Posted by GREGGPENN View Post
Or...a FFI intake/cam
Or...a SR intake/cam

Back in "the day", Lingenfelter chose the later.

Headers would help too. Will be hard to stay under $2k. It's been well communicated that the L98 has several obstacles (design features) specific to it's acceleration profile...that need "upgrade" for a different, more modern approach.

Edit: I missed pages 2-3 before reply above. It's still valid though I should have included the newer Edelbrock intake. Tuning will cost money when you are done...so don't forget that. As for the question about the difference in cam specs, you'd be better off going bigger than a stock LT1 cam for an upgrade...especially if you considered another intake beside the miniram.

The LT cam is a little better. The heads are too. Little improvements here/there add up....in addition to the inherent differences in the intakes. If you are comparing 3.73's vs 3.33, is probably, most likely, almost definitely the biggest difference you can feel in "street torque".
Greg not long after posting that I found that the only difference from whats in my L98 and whats sitting here on my desk is the lift by 0.030 and you're right that's not worth a cam swap. Do you know what the max lift and duration can be run? I'll look into it tomorrow if not.

Originally Posted by Kingtal0n View Post
I would leave the motor alone, do maintenance to it but dont spend money on it. It isn't worth any $$$ going into an old engine like that.

save up for the LS swap.

In the mean time use nitrous to get whatever power you want from it. Setup a progressive shot and install it well so that the next motor can also use it.
There are 2 things I have decided I would never do to my early 90's street cars. 1 is add N20, as a Firefighter/Paramedic I hate the idea of a filled bottle in a car on the street. I also only see it useful for a drag strip and I am too far from one to use it enough for the cost of install and upkeep. The second thing was an engine swap to anything but what was in it originally. This is a mix of the automotive purist in me and wanting to learn on a broad range of cars and engines how they react to different parts. Thanks for the suggestions though.
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Old 05-07-2018, 07:06 AM
  #52  
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Originally Posted by Space387 View Post
Greg not long after posting that I found that the only difference from whats in my L98 and whats sitting here on my desk is the lift by 0.030 and you're right that's not worth a cam swap. Do you know what the max lift and duration can be run? I'll look into it tomorrow if not.



There are 2 things I have decided I would never do to my early 90's street cars. 1 is add N20, as a Firefighter/Paramedic I hate the idea of a filled bottle in a car on the street. I also only see it useful for a drag strip and I am too far from one to use it enough for the cost of install and upkeep. The second thing was an engine swap to anything but what was in it originally. This is a mix of the automotive purist in me and wanting to learn on a broad range of cars and engines how they react to different parts. Thanks for the suggestions though.
Stroker motor with different intake and headers?
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Old 05-07-2018, 05:10 PM
  #53  
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Originally Posted by Space387 View Post
Do you know what the max lift and duration can be run?
Max lift on stock 113 heads is around .500". Machining will get you around that.

Your question about max duration is unusual. If you're thinking of much over 220 duration, don't do it under a TPI. Physical limits of duration are often more about "driveability" than anything. (Few exceed 235 duration cams unless racing). Selecting duration becomes a matter of personal taste in idle/low-speed characteristics of an engine....plus "matching" a cam to your chosen intake and application.

Generally, each intake has a range of ideal duration(s). Less duration might provide more torque (low-speed power) where more moves power higher...meaning you can tweak an intake/combo to "bend" toward your goals. You can't make a TPI act like a MR though. Beyond cams, intakes have their own physical limitations....which explains the second sentence of my prior paragraph.

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Old 05-08-2018, 01:44 AM
  #54  
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To be honest I wasn't sure how restrictive on cam size the L98 heads where. I know most gen 1 and gen 2 cams will fit the block but some exceed the operating limits of these heads.
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Old 05-08-2018, 03:35 AM
  #55  
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Originally Posted by Space387 View Post
To be honest I wasn't sure how restrictive on cam size the L98 heads where. I know most gen 1 and gen 2 cams will fit the block but some exceed the operating limits of these heads.
Examples to cover 113 head "limitations":

Stock results:
https://www.corvetteforum.com/forums...s-cam-l98.html

TPI Stroker with ported 113s and cam:
https://www.corvetteforum.com/forums...o-results.html

HSR Stroker with ported 113s and cam:
https://www.corvetteforum.com/forums...o-results.html

BTW...I captured the dyno that's missing from the HSR build (above).....


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Old 05-11-2018, 12:07 PM
  #56  
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ENGINE LABS -"A dual-plane manifold has a split opening in the plenum area directly below the carburetor mounting pad. Each side of the opening feeds four cylinders on a V8 engine. Single-plane manifolds have a single intake opening into the plenum and feeds all 8 cylinders directly. "

So who posted this as their definition of a dual plane? That T-flop intake feeds only 4 cylinders from 1 side of the manifold. That T-flop intake was just as bad as Holley Street Dominator Z intake with a plenum divider was. They all flopped their way into the junkpile.

That SLP Firehawk proved that intake was lame. They rebuilt the entire motor with better pistons and used headers only to make 350hp. And who knows what they did/spent on the heads? Cam? What a waste, the RamJet 350 makes more power on less compression using only iron heads. Fact is split plane intakes were flops! $40,000 in 1992? They should have called that car the overpriced FireFlop!
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Old 05-11-2018, 01:10 PM
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I dont know about you but we have moved on. Regardless of your take on single vs dual plane. Efi vs carb. Personally I dont care. When I have the car sorted out it will get either a LT1 or tpis intake. With a cam to match and probably some cleanup work on the heads like I did with my LT1. Thanks for your input
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Old 05-11-2018, 01:21 PM
  #58  
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work over an Lt1 intake theres no advantage to the miniram for a street car most times. They want crazy money for those anyways.
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Old 05-11-2018, 01:27 PM
  #59  
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Yikes. When does it end?

The Plenum in the T-ram is open from one side to the other. While visually I can see how a T-Ram would confuse a guy with your intelligence and observation skills, it's actually all one big open space behind the TB (no "split opening in the plenum") that each cylinder can "see".

That being the case, it's not a dual plane. However, lets have some fun for a minute and explore this a bit further, shall we? Let us just go ahead and pretend that it's not all open behind the TB -let's pretend that it is split down the middle by a divider (it's not). Sound like fun?

One of the important and distinguishing features of a dual plane intake (covered several times earlier in the thread, staring way back in post #36) is that the 4 cylinders pull from each plenum in even, 180 degree pulses. "Two plenums...each plenum connects to every other runner in the firing order" -2:00 in the video.
Does the T-Ram do that? Does it split the space behind the TB into two separate plenums? No, it does not. Does each "side" connect to every other runner in the firing order? No, it does not. Why doesn't it do that? Because it's not a dual plane intake. The cylinders are not divided, the plenum is not divided and the runners are not arranged such that there is 180 degree cylinder draws. THINK. Use your eyeballs and your brain.


Originally Posted by cardo0 View Post
That SLP Firehawk proved that intake was lame. They rebuilt the entire motor with better pistons and used headers only to make 350hp. And who knows what they did/spent on the heads? Cam? What a waste, the RamJet 350 makes more power on less compression using only iron heads. Fact is split plane intakes were flops! $40,000 in 1992? They should have called that car the overpriced FireFlop!
Wow...good one. You come up with that all by yerself?
First, the Firehawk was w/in ~20 hp of the LT5, passed emissions, had a warranty etc. It was over 100 more hp than it's TPI based foundation. That was pretty phenomenal in '92
Second; where do those changes come from? YOU DON'T KNOW...that's for sure. But the intake was a large part of the improvement.
Third, the Ramjet most certainly does NOT make more power than the Firehawk engine. The RamJet is rated in GROSS HP and...given the same ~350 rating! Yet the Firehawk was rated NET. Know the difference? I'm guessing that you don't so HERE IS SOME READING FOR YOU.



Originally Posted by cardo0 View Post
Fact is split plane intakes were flops!
But....you recommended one to the OP. (?)

I think the OP is probably "over it" with this part of the conversation. If he isn't, I know that I am. It's painfully obvious that you don't know what you're talking about and you can't use your eyeballs to read a definition and then see the difference between a single plane and dual plane intake. To mitigate any more damage to this thread, I'll just go ahead and agree with you:
*The OP should definitely use a dual plane intake for massive low end tq.
*You're obviously the God of engine knowledge. I bow to you.
*The T-Ram is junk

We good?

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Old 05-12-2018, 12:01 PM
  #60  
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Maybe a accel/lingenfelter Super Ram intake with a cam swap, headers and a tune would accomplish the OP's goals. Should still have lots of low end power and extend the power band at least 1000RPM higher....
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