LT4 hot cam
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Heel & Toe
Joined: Aug 2024
Posts: 22
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LT4 hot cam
Hello All,
I have a 1990 with a zf6speed that I want to put a mild cam in and I am hearing that an LT4 hot cam is a good choice. I have done cam swaps on carb motors before but never on a TPI. Can anyone tell me if I would need to do anything to the ECM with that cam. I am getting differing information when I look in to it. I am not looking to do to much to it right now other than the smog delete, headers and muffler delete.
If this cam is not viable what would a good option be to add a little more low to mid torque and add some aggressive sound on stock intake heads and block.
I have a 1990 with a zf6speed that I want to put a mild cam in and I am hearing that an LT4 hot cam is a good choice. I have done cam swaps on carb motors before but never on a TPI. Can anyone tell me if I would need to do anything to the ECM with that cam. I am getting differing information when I look in to it. I am not looking to do to much to it right now other than the smog delete, headers and muffler delete.
If this cam is not viable what would a good option be to add a little more low to mid torque and add some aggressive sound on stock intake heads and block.
Last edited by tglover101323; Sep 27, 2024 at 09:26 AM.
Instructor
Joined: Apr 2012
Posts: 194
Likes: 131
From: NJ
2025 Corvette of the Year Finalist - Modified
2024 C4 of the Year Winner - Modified
The usual story on the LT4 hot cam is that it's pretty mild and will give you reliable, proven power gains, but it's a nearly 30 year-old cam design and newer cams can offer better performance with the same reliability.
On a TPI engine, the intake is the limiting factor. If you're changing the cam, the engine's going to make more power at higher RPM, where the TPI intake runs out of steam. Low-to-mid range torque will still increase with the right cam, but you won't be able to take advantage of the higher-RPM power increase. The LT4 hot cam is mild, so you wouldn't be leaving as much on the table as you would with a larger cam, but it still wouldn't be at its full potential.
I think you should always get a tune when swapping cams, even with the LT4 hot cam. The engine will run better and make more power. Tunes aren't that expensive, so it's kind of silly not to do it.
On a TPI engine, the intake is the limiting factor. If you're changing the cam, the engine's going to make more power at higher RPM, where the TPI intake runs out of steam. Low-to-mid range torque will still increase with the right cam, but you won't be able to take advantage of the higher-RPM power increase. The LT4 hot cam is mild, so you wouldn't be leaving as much on the table as you would with a larger cam, but it still wouldn't be at its full potential.
I think you should always get a tune when swapping cams, even with the LT4 hot cam. The engine will run better and make more power. Tunes aren't that expensive, so it's kind of silly not to do it.
Team Owner
Joined: Sep 2001
Posts: 62,153
Likes: 1,731
From: Athens AL
C7 of the Year - Unmodified Finalist 2021
C4 of Year Finalist (performance mods) 2019
Hotcam is mismatched to that intake, it wants to breathe at higher RPM and would not be my choice. Something like a 210/220@050 with moderate lift would be a much better choice with a TPI on top.
Yes you do need the chip retuned for any cam change to optimize it out. You can get by with an AFPR and playing with timing, but if you want what you paid for, get the tune done.
Yes you do need the chip retuned for any cam change to optimize it out. You can get by with an AFPR and playing with timing, but if you want what you paid for, get the tune done.
Melting Slicks
Joined: Jul 2005
Posts: 2,214
Likes: 302
Hotcam is mismatched to that intake, it wants to breathe at higher RPM and would not be my choice. Something like a 210/220@050 with moderate lift would be a much better choice with a TPI on top.
Yes you do need the chip retuned for any cam change to optimize it out. You can get by with an AFPR and playing with timing, but if you want what you paid for, get the tune done.
Yes you do need the chip retuned for any cam change to optimize it out. You can get by with an AFPR and playing with timing, but if you want what you paid for, get the tune done.
The other thing is if you're currently running the original injectors, I'd replace them while you're at it. And since you're be doing a tune anyway, a good set of Bosch-III's are an easy upgrade (I generally don't recommend Bosch-III's if no tuning is being done since they're often hit or miss on whether they need a tune). Bosch P/N 280155715 are 24 lb @ 43 psi, and available from Southbay. In fact I actually just got done tuning a thirdgen.org member's 1990 TPI Camaro for a mild cam upgrade and those injectors. He got the Accel cam (the old Ligenfelter)... 211/219 @.050, .503/.525 lift, 112 LSA. He had also swapped to L98 Corvette heads in the process. He's thrilled with how it runs.
Drifting
Joined: Apr 2007
Posts: 1,291
Likes: 33
From: Chicago IL
Hello All,
I have a 1990 with a zf6speed that I want to put a mild cam in and I am hearing that an LT4 hot cam is a good choice. I have done cam swaps on carb motors before but never on a TPI. Can anyone tell me if I would need to do anything to the ECM with that cam. I am getting differing information when I look in to it. I am not looking to do to much to it right now other than the smog delete, headers and muffler delete.
If this cam is not viable what would a good option be to add a little more low to mid torque and add some aggressive sound on stock intake heads and block.
I have a 1990 with a zf6speed that I want to put a mild cam in and I am hearing that an LT4 hot cam is a good choice. I have done cam swaps on carb motors before but never on a TPI. Can anyone tell me if I would need to do anything to the ECM with that cam. I am getting differing information when I look in to it. I am not looking to do to much to it right now other than the smog delete, headers and muffler delete.
If this cam is not viable what would a good option be to add a little more low to mid torque and add some aggressive sound on stock intake heads and block.
Your car used a map sensor and yes new tune is needed.
I would ditch the the tpi intake and install a tpis miniram or LT1 converted intake manifold.
Pro
Joined: Mar 2006
Posts: 520
Likes: 143
From: Caribbean/Florida
The usual story on the LT4 hot cam is that it's pretty mild and will give you reliable, proven power gains, but it's a nearly 30 year-old cam design and newer cams can offer better performance with the same reliability.
On a TPI engine, the intake is the limiting factor. If you're changing the cam, the engine's going to make more power at higher RPM, where the TPI intake runs out of steam. Low-to-mid range torque will still increase with the right cam, but you won't be able to take advantage of the higher-RPM power increase. The LT4 hot cam is mild, so you wouldn't be leaving as much on the table as you would with a larger cam, but it still wouldn't be at its full potential.
I think you should always get a tune when swapping cams, even with the LT4 hot cam. The engine will run better and make more power. Tunes aren't that expensive, so it's kind of silly not to do it.
On a TPI engine, the intake is the limiting factor. If you're changing the cam, the engine's going to make more power at higher RPM, where the TPI intake runs out of steam. Low-to-mid range torque will still increase with the right cam, but you won't be able to take advantage of the higher-RPM power increase. The LT4 hot cam is mild, so you wouldn't be leaving as much on the table as you would with a larger cam, but it still wouldn't be at its full potential.
I think you should always get a tune when swapping cams, even with the LT4 hot cam. The engine will run better and make more power. Tunes aren't that expensive, so it's kind of silly not to do it.
