Instead of splicing two hoses together, why did you not installl one new hose from the throttle body to the heater core? It would eliminate a potential leak, give hood clearance, and likely be cheaper. Also, are you concerned about the zip tie chafing the hose? Thanks!
To eliminate the hose clamps one could run a new hose all the way from the engine block to the heater core. When removing heater hoses from the core it is a good idea to remove the clamp and cut the hose long way with a utility knife to prevent damage to the core tube.
Nice job, I did the TB bypass hose mod on my ‘87 too. You may want to consider removing the air pump. (If that’s legal in Utah) That way you can also remove all those vacuum hoses etc which are now getting in the way with the new coolant hose. Anyway, you routed it nicely. Btw I just use a ratchet to loosen the tensioner pulley.
My only concern on your coolant bypass is the obviously pinched hose as it curves off the manifold and back to the splice. I just bought a C4, so thanks for the informative vids. I had no idea the TPI had a coolant line running through it. What a terrible idea on the part of GM engineers. I'll keep you posted if I come up with a better plan for that coolant bypass. I'll tackle it soon.
Just did the Coolant Bypass and I just ran a whole new line all the way to the firewall. Putting a new Throttle Body on it so needed to do this anyway. In looking at the stock lines before I removed, it looks like the stock u-shaped hose can be turned towards the hose coming from the firewall and connected together. Not 100% sure, but it looks like it will work. But love the videos and they are very helpful.
@@chenlmax I honestly do not remember. This is my brothers vette, so I don't recall what size hose it was. I had extra hose laying around and it fit perfect. So I just used it.
Thanks for the video. This is my next mod. I think your next future modification should be to get rid of the smog / pollution crap. I did this and really cleans up the engine bay. By the way, my car is a 1988 dark blue like yours with saddle interior. Keep the videos coming. 👍
Already done all these long ago. Not as 'mods' to free or 'gain' hp, but to clean up the bay. Btw about the coolant bypass, once the engine is fully warmed up and heat soaked everything will be hot. Including the throttle body, plenum, runners, and air coming in ☻
I disagree. I’ve driven the car, pulled over, and touched the plenum and it is cool to the touch. It may heat up if you are at a stop light, or of course after you’ve driven it and parked it, but it is cool/cools down while driving and makes a difference. Check out the dyno results in the description of the video.
Cool vids,I just installed an ls 5.3 cam,sheet metal intake and Holley Terminator x ecu. Need a few more items before fire up,should have 425 hp as for your water pump pulley,u would have to move your aftermarket sway bar or one side of it. Keep up the good and informative vids.
Solid video as always. I want to do the TB bypass mod now. I hope it is as easy as you made it look. Did you get the hose, clamps, coupler, and vacuum caps at autozone? Is that really all the parts you need for this mod? Also, how do you burp the coolant? (Sorry for the newb questions)
Always à pleasure to see you New video !! Finaly is was suppose to Buy a C4 that was the reason i watch ur Channel but i hit a c5 luck ...with only 70k miles ,headers,Chip and x pipe so i Buy IT but i cant get it now because all the registration office are close due to the cov19
Honestly you don't need to cap off the coolant passages on the throttle body when doing the bypass. I'm just saying in case you wanted to save 6-8 bucks on buying those rubber caps
I am a new owner of an 1988 conv. C4 and came across your video. I'm going to backtrack and watch the previous ones in this collection, because I feel you did such a great job on this one. I have a question though, I noticed as I analyzed your engine bay that it looked like you did an AC conversion. If so, did you do a video on it? thanks so much, great work
Oh man. I’ll have to think on that to try and remember. The hose on my car is 5/8. I might have taken the hose with me to the store and tried a few different couplers.
Those dreadful hose clamps crimp under their screws. There are clamps that are nicer that put pressure evenly all around the hose and are also less likely to cut and create leaks. Great job however, thanks!
The "frisbee mod" will free up ZERO horsepower, because it doesn't restrict horsepower in the first place. It has a flywheel effect, but that's all. To get the pulley out, remove the aftermarket chassis brace.
it seems like less rotational mass would result in the engine needing to work less hard to keep itself spinning. same reason for buying lighter wheels, yes?
@@samstrolia Yes, but if you dyno test both setups there will be no difference in horsepower or torque. The flywheel is not part of the engine, it's an external device being driven by the engine, so it can't add or subtract power. Nor does it add any parasitic drag to speak of, which is an important distinction. What a flywheel does do is add inertia to a rotating assembly. All other things being equal, a lighter flywheel speeds up quicker, slows down quicker, and is less able to dampen vibration. The engineers determined that this frisbee thing was necessary, and GM SPENT MONEY to install it. Millions of small block Chevy engines were sold without this device, yet here it is on the Corvette's L98. Logically, it serves to dampen some problematic vibration, or to dampen a shock load like the cycling of the AC compressor, in this particular accessory drive system. So then backyard engineers look at it, but don't understand its purpose. Based on that solid foundation, they decide it's unnecessary and remove it. Because, you know, GM's professional engineers were obviously stupid to install it in the first place.
@@Michael_Lorenson if this disk were to weigh much more, say 100lbs, then it would have a noticable affect on the performance, given it's resistance to accelerate (inertia). Every time you rev through a gear, the engine has to rotate that part as well as the pulleys, etc. It is rotational mass that is moved due to energy provided by the engine. Obviously the disk only weighs a few pounds, so I wouldn't argue that it would be a noticable difference in power or torque, but it does to some extent affect the performance of the engine. If what you're saying is true, then something like an ac delete wouldn't cause any difference in performance. This is using the engines energy in the same way, being that it is an outside force of resistance, also on the accessory drive. I don't mean to cause conflict by the way, but just am interested from the physics perspective of things.
@@samstrolia Yes, I agree that we can have a civil conversation about this. I said a flywheel does not cause more than negligible net parasitic drag, which is correct. I also said there would be no effect on dyno results. Yeah, that part was WRONG. Energy (engine output) is taken and stored by the flywheel during acceleration, which slows the rate of acceleration. Then it is given back during deceleration, which slows the rate of deceleration. So all of the energy stored in the flywheel is ultimately available for use. Its inertia resists change, like all right-thinking inertias do, and the result is smoother response that is easier for the driver to control. But, it does so by robbing acceleration to pay for resisting deceleration. The dyno measures the engine ONLY in acceleration mode. But the flywheel gives its stored energy back ONLY in deceleration mode. That energy can't contribute to the dyno pull; it's all 'lost' in that scenario. As far as the dyno is concerned, the stored energy only manifests as reduced torque. Horsepower is calculated directly from torque and RPM. Therefore, less flywheel weight = more power on the dyno. Duh! Your analogy using the AC compressor is correct in acceleration mode. But, the AC compressor ONLY contributes drag, which continues during deceleration. All the energy delivered to the compressor manifests as compressor function and heat. That's parasitic drag. Since the flywheel, in principle, gives all its stored energy back, it's not a net parasite. I say 'in principle' because some amount of stored energy can be lost to dampening vibration, or overcoming aerodynamic resistance. Finally (it's about time, right?), I agree that the frisbee does not store enough energy to be felt by the driver. The weight of an extra gallon of gas in the tank might have a bigger effect. But it does store enough energy to smooth out the operation of the accessory drive system in some way that affects NVH or reliability, or both. Otherwise it just wouldn't be there.
Seems like you are chasing HP. leave it stock.. With cars pushing over 700HP, you are never gonna the win HP war. You should have spice the lines closer to the wall so it it not a eye sore when looking at the motor.
So great to see somebody giving some nice hints for the C4. I'll try this on my c4, too. Plz more of your videos 😎
Instead of splicing two hoses together, why did you not installl one new hose from the throttle body to the heater core? It would eliminate a potential leak, give hood clearance, and likely be cheaper. Also, are you concerned about the zip tie chafing the hose? Thanks!
That’s what I did I don’t trust a pipe and it will make a miss of unnecessary of coolant hose’s
To eliminate the hose clamps one could run a new hose all the way from the engine block to the heater core. When removing heater hoses from the core it is a good idea to remove the clamp and cut the hose long way with a utility knife to prevent damage to the core tube.
Nice job, I did the TB bypass hose mod on my ‘87 too. You may want to consider removing the air pump. (If that’s legal in Utah) That way you can also remove all those vacuum hoses etc which are now getting in the way with the new coolant hose. Anyway, you routed it nicely. Btw I just use a ratchet to loosen the tensioner pulley.
My only concern on your coolant bypass is the obviously pinched hose as it curves off the manifold and back to the splice. I just bought a C4, so thanks for the informative vids. I had no idea the TPI had a coolant line running through it. What a terrible idea on the part of GM engineers. I'll keep you posted if I come up with a better plan for that coolant bypass. I'll tackle it soon.
Just did the Coolant Bypass and I just ran a whole new line all the way to the firewall. Putting a new Throttle Body on it so needed to do this anyway. In looking at the stock lines before I removed, it looks like the stock u-shaped hose can be turned towards the hose coming from the firewall and connected together. Not 100% sure, but it looks like it will work. But love the videos and they are very helpful.
Thanks, Bill.
What year C4? What size hose did you run from the manifold outlet to the heater core inlet?
@@chenlmax I honestly do not remember. This is my brothers vette, so I don't recall what size hose it was. I had extra hose laying around and it fit perfect. So I just used it.
Thanks for the video. This is my next mod. I think your next future modification should be to get rid of the smog / pollution crap. I did this and really cleans up the engine bay. By the way, my car is a 1988 dark blue like yours with saddle interior. Keep the videos coming. 👍
Already done all these long ago. Not as 'mods' to free or 'gain' hp, but to clean up the bay. Btw about the coolant bypass, once the engine is fully warmed up and heat soaked everything will be hot. Including the throttle body, plenum, runners, and air coming in ☻
I disagree. I’ve driven the car, pulled over, and touched the plenum and it is cool to the touch. It may heat up if you are at a stop light, or of course after you’ve driven it and parked it, but it is cool/cools down while driving and makes a difference. Check out the dyno results in the description of the video.
Snap off the zip tie and re-zip it to the coolant hose...that'll knock it down about a 1/2 inch.
Cool vids,I just installed an ls 5.3 cam,sheet metal intake and Holley Terminator x ecu. Need a few more items before fire up,should have 425 hp as for your water pump pulley,u would have to move your aftermarket sway bar or one side of it. Keep up the good and informative vids.
Wonder if removing the frisbee will help with fuel mileage? Of course, if you’re worried about mileage then you probly shouldn’t but a Corvette…🙀
Solid video as always. I want to do the TB bypass mod now. I hope it is as easy as you made it look. Did you get the hose, clamps, coupler, and vacuum caps at autozone? Is that really all the parts you need for this mod? Also, how do you burp the coolant? (Sorry for the newb questions)
Couldn't see the vacuum plugs that good. Did you have to put clamps on them also? I have a 1990 c4 with a 6 speed I doing. Thanks
No clamps. They slipped on and were pretty snug. They are 5/8 in size.
How do you burp the cooling system?
Always à pleasure to see you New video !! Finaly is was suppose to Buy a C4 that was the reason i watch ur Channel but i hit a c5 luck ...with only 70k miles ,headers,Chip and x pipe so i Buy IT but i cant get it now because all the registration office are close due to the cov19
I just want to get home from this deployment and work on my c4 😪
Thanks for your service 🙏🇺🇸.
RuNGun 99 - come home safely thank u 4 your services.
What specific caps/plug did you use for there bypass inlet and outlet?
It was just an assortment pack that I got from Autozone. I used the biggest ones from the pack (I think they are 3/4 inch).
@@ReynoldsRides Thanks! Keep em coming. enjoy watching.
🙏👊
Honestly you don't need to cap off the coolant passages on the throttle body when doing the bypass. I'm just saying in case you wanted to save 6-8 bucks on buying those rubber caps
I've seen a throttle body hose kit by LCO design -_- one hose curved to fit
One piece hose, cap off the 2ports
Plan to install my 95
Where you routed the new hose on top of, doesn't that go to the smog pump? Couldn't you remove all of that equipment?
I am a new owner of an 1988 conv. C4 and came across your video. I'm going to backtrack and watch the previous ones in this collection, because I feel you did such a great job on this one. I have a question though, I noticed as I analyzed your engine bay that it looked like you did an AC conversion. If so, did you do a video on it? thanks so much, great work
Hi,
I have a '90 and want to do the TB bypass...what size brass coupler did you use and where did you get it? Thanks for the videos, nice job! 👍🏻👍🏻
Oh man. I’ll have to think on that to try and remember. The hose on my car is 5/8. I might have taken the hose with me to the store and tried a few different couplers.
Those dreadful hose clamps crimp under their screws. There are clamps that are nicer that put pressure evenly all around the hose and are also less likely to cut and create leaks. Great job however, thanks!
Thanks!
coolant does not actually run through the TB, It runs through the IAC housing, it keeps the IAC from icing up under cold conditions.
You’re kind of splitting hairs. The IAC housing is part of the throttle body but I get what you are saying. I try to keep things high level.
I wonder how much hp doing those and the airbox mod does.
Looks like the previous owner installed the throttle body air foil as well.
That was me 😉: ua-cam.com/video/k0HeB09di_0/v-deo.html.
Oh yeah. I went back and rewatched the build series. Alot of good info. I am on the look out for a 96 six speed vette with the LT4.
Can I do these on 84 c4
How I can find a air leak air vacuum leak in my C4 Corvette 1989
Why not just add an inline valve you can turn it on and off at will
How do you burp the system for air ? I’m
Doing this mod this weekend? Thanks patna
Joseph M -I do the same thing to my cars good word (burp)
Joseph M I couldn’t figure it out, so I hooked everything up already and started it, will it affect the vehicle if i don’t burp it?
@@bobuardobobuardo9059 No, it will burp itself.
Glad I didn't get a ZR1.
use 1/2 copper
The "frisbee mod" will free up ZERO horsepower, because it doesn't restrict horsepower in the first place. It has a flywheel effect, but that's all. To get the pulley out, remove the aftermarket chassis brace.
it seems like less rotational mass would result in the engine needing to work less hard to keep itself spinning. same reason for buying lighter wheels, yes?
@@samstrolia
Yes, but if you dyno test both setups there will be no difference in horsepower or torque. The flywheel is not part of the engine, it's an external device being driven by the engine, so it can't add or subtract power. Nor does it add any parasitic drag to speak of, which is an important distinction.
What a flywheel does do is add inertia to a rotating assembly. All other things being equal, a lighter flywheel speeds up quicker, slows down quicker, and is less able to dampen vibration.
The engineers determined that this frisbee thing was necessary, and GM SPENT MONEY to install it. Millions of small block Chevy engines were sold without this device, yet here it is on the Corvette's L98. Logically, it serves to dampen some problematic vibration, or to dampen a shock load like the cycling of the AC compressor, in this particular accessory drive system.
So then backyard engineers look at it, but don't understand its purpose. Based on that solid foundation, they decide it's unnecessary and remove it. Because, you know, GM's professional engineers were obviously stupid to install it in the first place.
@@Michael_Lorenson if this disk were to weigh much more, say 100lbs, then it would have a noticable affect on the performance, given it's resistance to accelerate (inertia). Every time you rev through a gear, the engine has to rotate that part as well as the pulleys, etc. It is rotational mass that is moved due to energy provided by the engine.
Obviously the disk only weighs a few pounds, so I wouldn't argue that it would be a noticable difference in power or torque, but it does to some extent affect the performance of the engine.
If what you're saying is true, then something like an ac delete wouldn't cause any difference in performance. This is using the engines energy in the same way, being that it is an outside force of resistance, also on the accessory drive.
I don't mean to cause conflict by the way, but just am interested from the physics perspective of things.
@@samstrolia
Yes, I agree that we can have a civil conversation about this.
I said a flywheel does not cause more than negligible net parasitic drag, which is correct. I also said there would be no effect on dyno results. Yeah, that part was WRONG.
Energy (engine output) is taken and stored by the flywheel during acceleration, which slows the rate of acceleration. Then it is given back during deceleration, which slows the rate of deceleration. So all of the energy stored in the flywheel is ultimately available for use. Its inertia resists change, like all right-thinking inertias do, and the result is smoother response that is easier for the driver to control. But, it does so by robbing acceleration to pay for resisting deceleration.
The dyno measures the engine ONLY in acceleration mode. But the flywheel gives its stored energy back ONLY in deceleration mode. That energy can't contribute to the dyno pull; it's all 'lost' in that scenario. As far as the dyno is concerned, the stored energy only manifests as reduced torque. Horsepower is calculated directly from torque and RPM. Therefore, less flywheel weight = more power on the dyno. Duh!
Your analogy using the AC compressor is correct in acceleration mode. But, the AC compressor ONLY contributes drag, which continues during deceleration. All the energy delivered to the compressor manifests as compressor function and heat. That's parasitic drag.
Since the flywheel, in principle, gives all its stored energy back, it's not a net parasite. I say 'in principle' because some amount of stored energy can be lost to dampening vibration, or overcoming aerodynamic resistance.
Finally (it's about time, right?), I agree that the frisbee does not store enough energy to be felt by the driver. The weight of an extra gallon of gas in the tank might have a bigger effect. But it does store enough energy to smooth out the operation of the accessory drive system in some way that affects NVH or reliability, or both. Otherwise it just wouldn't be there.
@@Michael_Lorenson are you talking about a flywheel as in drivetrain component touching the clutch disk? Or the 4lb disk on the front on the engine?
Drinking game, take a shot every time he says serpentine...
How many shots would that be?
Seems like you are chasing HP. leave it stock.. With cars pushing over 700HP, you are never gonna the win HP war. You should have spice the lines closer to the wall so it it not a eye sore when looking at the motor.
Do I want more hp than 240? Yes. Am I trying to win a hp war? No. The lines look fine to me and that’s all that matters.