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Converting LT1 to later hose layout, throttle bypass
Just in case it helps someone, here are the hoses to completely replace everything and bypass the throttle body coolant passage…did this to my 93:
ACDelco 35 14329S *heater hose, J shaped
ACDelco 35 24408L *95+ upper radiator hose without T to throttle body
ACDelco 35 18140L *95+ heater hose without T to throttle body
ACDelco 35 24409L *lower radiator hose
GM Genuine 15 10157913 *heater hose with flow restrictor
This mod reduces intake temps and eliminates some potential coolant leak locations.
So I guess this eliminates the "T" coming off the top drivers side of the radiator, and the "T" on the water pump / throttle body correct? The one on the passenger side is a big change too. Basically turns a 93 into a 95 design? 93 top hose replaced... Will look like my 95.. This 93 hose coming off the throttle body goes too? 93 off the TB tees into hose coming off the water pump. These get replaced too? Will eventually look like this TB elimination, correct on my 95?
Yes.. both T’s that run to the throttle body go away…
The J hose is from the heater core at the firewall to the surge tank. The hose with the restrictor goes from the water pump to the heater core at the firewall.
Thanks for the post. I'll go check those. Did you find they needed to be replaced after looking at them (when pulled), or was it just a refresh thing?
So, you cleaned the TB and just did the coolant delete. Is the thought, this just doesn't need coolant given the TB is not impacted by heat and the cars typically are not cold weather operated?
My hoses were pretty gross on the inside but my cooling system was not maintained like it should have been. Some of the smaller hoses looked “bulged” where they attached…I mean they are 30 year old rubber so it was time…
There are lots of threads and info out there about the TB bypass, including for Camaros etc. In general it:
- cleans up the hose routing
- eliminates potential leak spots
- allows cooler air to enter the intake, maybe in some circumstances resulting in a small amount of power increase
Drawbacks:
- emissions might suffer very slightly due to lower air temp once fully warmed up (I’m not sure anyone has measured this?)
- there is an unlikely scenario in very cold weather that the throttle body could “freeze”. I drive mine in the cold when roads are not salted and am not worried about this…I’ve not been able to find any documented case of this happening to anyone who has made this tweak… and the throttle body starts out ambient anyway and gets heat from the intake etc…anyway…. but MAYBE in the right humidity with extended cruise on the highway with the right temp….maybe.
Has there been a legitimate means of measuring the actual temperature of the air downstream of the throttle body before and after the modification?
I think that once the engine has been running for any substantial timeframe(especially in warmer climate), heat soak will probably nullify the effect of not running coolant through the throttle body.
Has there been a legitimate means of measuring the actual temperature of the air downstream of the throttle body before and after the modification?
I think that once the engine has been running for any substantial timeframe(especially in warmer climate), heat soak will probably nullify the effect of not running coolant through the throttle body.
I have read there are dyno results. But let’s say it’s always 0 power benefit. That’s fine, I did NOT do it for that reason, at all…
Will this work on a 92, I would like to replace all my cooling system hoses and would like to eliminate the TB cooling at the same time. I don't see that I would use all 5 hoses on my 92?
It looks like the 92 and 93 are different. The 93 has two heater hoses going to the water pump where the 92 only has one. I kept on looking at the pictures in the thread and got confused every time I looked at my 92. I would have to change my water pump as well.
Hey is there a video on the instalation of these hoses. i have a 93' that had shitty owner and they did a shitty hose job on it.
Do you mean your hoses don't look like the factory routing? On a 93 there is a smaller hose 'in' (front/drivers side) then out (passenger side) of the throttle body. You are basically removing each of those segments to where each "T" into a hose. You could just cap at the T of each hose and you are done with the bypass. But by using the later year upper radiator hose and heater supply hose, you put in a single line for each that doesn't have a T.
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Converting LT1 to later hose layout, throttle bypass
