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How would an aftermarket LT1 intake with long runners effect the performance?!

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Old 10-10-2017, 09:01 PM   #1
Phoenix'97
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Default How would an aftermarket LT1 intake with long runners effect the performance?!

I am not the first person, nor shall I be the last, to inquire about a bolt-on TPI style intake for the LT1 motor. My car is a daily driver and right now I am soul searching with what I want to do with the motor. I don't need a suped up race car with 4.10 rear gears and an aggressive camshaft with ported heads and upgraded valvetrain and the whole nine yards! I do, however, want more low to mid-range torque that I can feel immediately and that gives me an enjoyable daily driver that is fun to launch from green lights or aggressively accelerate where safe to do so in the city. I have no intention of butchering my motor to try to fit and fabricate a stock L98 TPI intake. I do, however, intend to seek out a company that can make this custom intake that is a genuine bolt-on with all necessary sensor attachments and emissions controls. However, I need expert advice on whether or not a dedicated LT1 intake with long runners will be detrimental to the motor or not. I assume the CPU can handle the adjustments with the intake and as far as driving below 5000 RPM, there shouldn't be any problems but again this is an LT1 and not an L98 with a different fuel injection design. So, am I correct in my logic that this intake will give me the low to mid-range "umpf" that I am seeking, or do I have it all butt backwards?!
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Old 10-11-2017, 07:44 AM   #2
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It might be cheaper and easier to look at cam options. The LT1 is capable of making a lot of midrange power, hell it does out of the box, you give up very little to an L98...it is noticeable but its not a lot. I'd probably look at cam options vs intake/runner custom fabrication.
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Old 10-11-2017, 12:31 PM   #3
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It might be cheaper and easier to look at cam options. The LT1 is capable of making a lot of midrange power, hell it does out of the box, you give up very little to an L98...it is noticeable but its not a lot. I'd probably look at cam options vs intake/runner custom fabrication.

Thank you for your comment and answering my question. Yes, I understand that I could be paying a pretty sum to have a legit and reputable business produce a possible one-off TPI style intake that is a direct bolt-on for the LT1 which is also low enough to clear the hood and fit any other LT1 vehicle. Then again, I stand to spend lots of money doing the other thing by focusing on increased air flow and more power production on the top end, and with the rear gear. I can always get a price quote and decide if I am willing to take that step. Who knows, this could provide a new product for the LT1 community if anyone is interested. For the driving I do which is quite tame and necessary for the unpredictable and dangerous bumper-to-bumper city driving, I really can't go all that fast so why put in a lower rear gear when my stock gear is really perfect for the driving conditions. This is why I want every bit of low end to mid-range torque that I can get, to intentionally optimize my LT1 for this power band. I may not be quick at the track but I can have my fun at the green lights.
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Old 10-11-2017, 01:15 PM   #4
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It seems to me, the thousands you will spend to have said intake system designed and built for an otherwise stock LT1 to have "mid-range" power, that there are a dozen other ways to achieve it. Gears, cam, tuning, heck even nitrous, considering you want to "have fun at the green lights".






I'd personally look into all options before spending a dime on this intake system you're considering.
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Old 10-11-2017, 01:34 PM   #5
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Generally long runners improve low end torque. If they are too long high rpm power is lost. Short runners are good for top end power at the expense of low end torque. Plenum size is also a factor, in some cases increasing its volume can be beneficial. The factory design is somewhere in the middle. One of the coolest intakes had individual runners that moved up and down increasing and reducing length with engine load. There was a " Super Ram" type intake for the LT1 at one time. It's being many years since I saw one. It offers longer runners and larger plenum than stock. I never saw a dyno test of it.
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Old 10-11-2017, 01:41 PM   #6
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I know you are only wanting to change the intake but I'm going to give one more vote for a cam change instead. I purchased an entire kit from Bullet Cams (Cam, Springs, Retainers, Keepers, and lifters) for roughly $800. I then bought a used set of long tube headers ($300) , Roller Rockers ($250), Hardened push rods ($100), guide plates ($50), and a gasket set ($150). So with a total of $1650 for parts and another $200 to get it dyno tuned so $1850 total. I'm making 380fwhp at 5500. But, starting at 1700rpm I'm at 375 ft-lbs. It climbs to 420ft-lbs at 3500 (80ft-lbs over the L98 peak at 3200rpm) then tapers down to 360ft-lbs at 6000rpm where we stopped. So with just a cam, headers, and rockers It gained 80hp and 90ft-lbs of torque with a really flat torque curve from the start. It has a ton of low end drivability and honestly after the tuning was finished, it is way more drivable at lower rpm than it was stock. I can ride at 800 rpm in 6th gear all day through town. As long as I just ease into the throttle to make a change it does great. So essentially, $1850 = 80hp, 90ft-lbs. There are other cams that would've made more power but I wanted something easily streetable. Cam specs: Duration @ 0.050, 220 intake, 226 exhaust; Lift: 0.530; LSA: 113 degrees.

-Colton
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Old 10-11-2017, 02:34 PM   #7
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Funny thread.

LPE made an SR for the LT1.

So... The LT1 intake is "almost" perfect IMO. there are better options for other engines, but you should really do some real research first before coming up with cool ideas on engine mods. The main drawback is distribution not power.

The Lt1 intake can support 600+hp If you look at the torque curve it's pretty good. It responds well to gears and other supporting mods. The best store bought bolt on is the HSR all hogged out, plenum made larger for more volume and ideally you want power more than anything so cut your hood open.

There are people here running lt1 intakes on cars running in the 9's in bad air.

go ahead and seek aftermarket intakes, OR simply realize an intake is not going to change your SOTP feel like you think a LTR intake will do.

I have owned:
MR
SR
Motown Single plane
Holley strip dominator single plane
HSR
L98 tpi stock
L98 tpi ported and siamesed.

If you were serious about getting an intake built from scratch, why not get something like an LS model that we know is killer?

or drop an L98 in and let yer neck snap off....

What year is your car?
What gear is your car?
What trans is your car?

If 92+ auto, feel free to throw in some 3.73 gears and forget this whole idea. After that it is down to money and how fast you want to go.
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Old 10-11-2017, 02:43 PM   #8
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finding one of those superrams will be impossible and guys want stupid money for them, not worth it

Gears headers and a modest cam (nothing rumpity) will be more than enoguh to do what you want. Add 15 deg +- on that cam it will feel plenty torquey and not shake the car. Some headwork does wonders, even a gain of 20-30 cfm is easily done dont need big valves or tons of money to get there.

Thats a good intake hang on to it

Last edited by cuisinartvette; 10-11-2017 at 02:46 PM.
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Old 10-11-2017, 04:08 PM   #9
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Quote:
Originally Posted by cuisinartvette View Post

finding one of those superrams will be impossible and guys want stupid money for them, not worth it

Gears headers and a modest cam (nothing rumpity) will be more than enoguh to do what you want. Add 15 deg +- on that cam it will feel plenty torquey and not shake the car. Some headwork does wonders, even a gain of 20-30 cfm is easily done dont need big valves or tons of money to get there.

Thats a good intake hang on to it


Gears alone would bring the effective RWT above that a healthy stock L98 (TPI and all) will produce. AND, because the LT1 has a significantly wider torque profile, There would be NO practical loss of top end speed either.

And, the nice thing about gears, is they're passive! The rest of drive train and its reliability is untouched!

It's truly having your cake and eating it too!!
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Old 10-11-2017, 06:30 PM   #10
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With everything said above.



Quote:
Originally Posted by Phoenix'97 View Post
I do, however, want more low to mid-range torque that I can feel immediately and that gives me an enjoyable daily driver that is fun to launch from green lights or aggressively accelerate where safe to do so in the city.
Stroker crank. WAY cheaper than the intake that you're fantasizing about and unlike the intake, a stroker crank will actually make the different in FEEL, that you want.

FYI, the '92 LT1 was only 10 ft lbs down on the L98 peak tq...every other year was the same....and according to GM the LT1 actually made more low RPM tq. The tq isn't all about the intake.

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Old 10-11-2017, 06:53 PM   #11
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imo the big torque debate between the two is just throttle response, theres lots of airspeed with the tpi so it may seem it has more torque than it does. Running out of air at 4500 just sucks...passing someone at 65 feels like a quick jolt then someone let off the gas.
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Old 10-11-2017, 06:58 PM   #12
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you want more torque, buy a C6 with a LS3
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Old 10-11-2017, 07:12 PM   #13
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LOL^


Quote:
Originally Posted by cuisinartvette View Post
Running out of air at 4500 just sucks...passing someone at 65 feels like a quick jolt then someone let off the gas.
Totally! The other day I took the 'Vette Kart out for a spin w/my boy ('89 TPI). We got to a piece of road that was straight and clear...I was rolling about 25 mph-ish? I double clutched into 1st and hit the gas...instantly the engine was "revving high" (no tach yet) but not really accelerating much; I was thinking, "Man, maybe this thing isn't that fast". I waited a bit longer for something to happen (which didn't) and then I grabbed 2nd gear and damn the car took off! Apparently, I was already beyond 4500 in 1st and just over revving the thing. Sure didn't sound like it though. I thought it would be right in the "meat" of the power curve. I need to get a tach in that thing.


.

Last edited by Tom400CFI; 10-11-2017 at 07:14 PM.
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Old 10-11-2017, 07:43 PM   #14
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Now I am getting overwhelmed with the diverse opinions! I have thought about a motor swap, especially the 2014 LT1 or even the 2015 LT4. The problem is, IT WILL BE EXPENSIVE to not only buy a turn-key crate engine but the transmission to accompany it, the ECM that my car will need, the modifications required to get it to fit my car, and even to wire everything up to my stock gauge clusters. Those thousands of dollars on a mere intake, and a custom grind camshaft are far more economical by comparison! Despite the LS family of motors being the "superior" motor to get, I have grown attached to my LT1. I love the way it sounds with the Magnaflow exhaust I have on it and frankly speaking I still feel that there is more I can do to improve upon this motor. It may never compare to the newest LS or even the next gen LT motors, but my goal is to produce a torque monster for daily driving, something that will allow me to use my factory rear gear ratio for better economy and yet have enough low end grunt to throw me back in my seat during aggressive acceleration from a stop.

Now, I am not expecting to make breakneck low end to mid-range torque from this intake alone. I realize I will need the necessary custom grind camshaft to do this. However, I won't need to go into mild porting my heads or concerning myself with more air flow from my motor so this build should be comparable to what I would spend to make myself a decent track car. Again, for any company to take on this task of developing the right long runner intake for my car, some research and development is going to be required. However, this is where I am hoping that the company which produced the FIRST aftermarket TPI intake can also make a bolt-on version for the LT1. If this can not be done, then I may be crazy enough to find a company to fabricate me a cross-ram stack EFT throttle body intake which will have the necessary plumbing to my factory air box and which must have the same emissions control attachments and PCV system as the LT1 intake. There was one company that expressed interest a way back when I was asking around about such an intake before. The cross-ram EFI throttle body intake produces instant low end to mid-range power but starts to fall behind when compared to the LS intake at high RPM. Even so, such an intake is ideal for my build.

Last edited by Phoenix'97; 10-11-2017 at 07:44 PM.
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Old 10-11-2017, 08:36 PM   #15
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Anything is possible if you put enough dollars in it. The Super Ram l98 intake can be modified to fit the LT1 BY a competent machine/fab shop. You may have 2 k in it between buying and modifying intake. I'm thinking you want it to look good, not cobbled up. A factory TPI maybe half with stock runners and plenum. The problem with TPi is manifold is in pieces, and it all needs tweaked together to accomplish your goal. You will need a new tune also.
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Old 10-11-2017, 08:37 PM   #16
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Quote:
Originally Posted by Phoenix'97 View Post
Now I am getting overwhelmed with the diverse opinions! I have thought about a motor swap, especially the 2014 LT1 or even the 2015 LT4. The problem is, IT WILL BE EXPENSIVE to not only buy a turn-key crate engine but the transmission to accompany it, the ECM that my car will need, the modifications required to get it to fit my car, and even to wire everything up to my stock gauge clusters. Those thousands of dollars on a mere intake, and a custom grind camshaft are far more economical by comparison! Despite the LS family of motors being the "superior" motor to get, I have grown attached to my LT1. I love the way it sounds with the Magnaflow exhaust I have on it and frankly speaking I still feel that there is more I can do to improve upon this motor. It may never compare to the newest LS or even the next gen LT motors, but my goal is to produce a torque monster for daily driving, something that will allow me to use my factory rear gear ratio for better economy and yet have enough low end grunt to throw me back in my seat during aggressive acceleration from a stop.

Now, I am not expecting to make breakneck low end to mid-range torque from this intake alone. I realize I will need the necessary custom grind camshaft to do this. However, I won't need to go into mild porting my heads or concerning myself with more air flow from my motor so this build should be comparable to what I would spend to make myself a decent track car. Again, for any company to take on this task of developing the right long runner intake for my car, some research and development is going to be required. However, this is where I am hoping that the company which produced the FIRST aftermarket TPI intake can also make a bolt-on version for the LT1. If this can not be done, then I may be crazy enough to find a company to fabricate me a cross-ram stack EFT throttle body intake which will have the necessary plumbing to my factory air box and which must have the same emissions control attachments and PCV system as the LT1 intake. There was one company that expressed interest a way back when I was asking around about such an intake before. The cross-ram EFI throttle body intake produces instant low end to mid-range power but starts to fall behind when compared to the LS intake at high RPM. Even so, such an intake is ideal for my build.
Pologreen above asked the following:
What year is your car?
What gear is your car?
What trans is your car?

That's important stuff...

Also, do you just want to be different? If that's the case do what you want its your car and sometimes being different is fun. If it's just torque you're after you can make plenty of it on the LT1 intake without the TPI compromises. I would focus on building the LT1, for relatively little money you can make serious power and torque over a stock LT1.
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Old 10-11-2017, 08:53 PM   #17
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Anything is possible if you put enough dollars in it. The Super Ram l98 intake can be modified to fit the LT1 BY a competent machine/fab shop. You may have 2 k in it between buying and modifying intake. I'm thinking you want it to look good, not cobbled up. A factory TPI maybe half with stock runners and plenum. The problem with TPi is manifold is in pieces, and it all needs tweaked together to accomplish your goal. You will need a new tune also.
Well, I really have my heart set on the FIRST TPI intake. The Super Ram is more focused on higher end power production with increased flow necessary for it. The FIRST TPI intake is a happy compromise, it offers more air flow over the stock TPI but it doesn't sacrifice much of the low end torque, starting at 2000 RPM, so other forums have claimed from user experience. However, I am not against using the factory TPI intake. Again, I don't have many opportunities to go fast when traffic is light and no one is in the lane I am in. Also, I don't rev past 5000, if I can't pass a car before then, I need more power production in the low to mid-range, this is how I see it. I hate hearing what sounds like my engine straining when I am near the factory rev limiter anyways!
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Old 10-11-2017, 09:01 PM   #18
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Quote:
Originally Posted by 6SpeedTA95 View Post
Pologreen above asked the following:
What year is your car?
What gear is your car?
What trans is your car?

That's important stuff...

Also, do you just want to be different? If that's the case do what you want its your car and sometimes being different is fun. If it's just torque you're after you can make plenty of it on the LT1 intake without the TPI compromises. I would focus on building the LT1, for relatively little money you can make serious power and torque over a stock LT1.
Year: 1997
Rear Gear Ratio: 3.42:1 stock
Transmission: 6 speed manual


Well, I already am different granted my build plans for this car which has nothing to do with strip performance and is even seen as performance degradation. I want to build this car the right way but with emphasis on maximum torque production from idle to 5000 RPM, I don't even want to bother with high revving as this car is a daily driver. This is where my "crazy" logic comes in to swap out the higher flowing LT1 intake for a TPI style intake OR if I am unable to do this, find someone to custom build an electronic fuel injection cross-ram stack throttle body intake that bolts on directly to the LT1. There needs to be the mandate that it have a PCV system and hook ups for emissions control devices. The company that expressed interest initially never mentioned these crucial systems on their intake system. So, it may not happen!

So, what do you recommend on how to build this motor without requiring a higher gear ratio?
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Old 10-11-2017, 09:06 PM   #19
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You have a C5 which should have a LS 1 not compatible with earlier gen I or II engines. C5 guys may have ideas
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Old 10-11-2017, 09:12 PM   #20
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Quote:
Originally Posted by Phoenix'97 View Post
Year: 1997
Rear Gear Ratio: 3.42:1 stock
Transmission: 6 speed manual


Well, I already am different granted my build plans for this car which has nothing to do with strip performance and is even seen as performance degradation. I want to build this car the right way but with emphasis on maximum torque production from idle to 5000 RPM, I don't even want to bother with high revving as this car is a daily driver. This is where my "crazy" logic comes in to swap out the higher flowing LT1 intake for a TPI style intake OR if I am unable to do this, find someone to custom build an electronic fuel injection cross-ram stack throttle body intake that bolts on directly to the LT1. There needs to be the mandate that it have a PCV system and hook ups for emissions control devices. The company that expressed interest initially never mentioned these crucial systems on their intake system. So, it may not happen!

So, what do you recommend on how to build this motor without requiring a higher gear ratio?
1997 is an LS1 car, that's the first year of the C5. Completely different animal and as mentioned above not compatible with prior SBC parts.
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