TB Coolant Crossover/Bypass, Any Disadvantages? - ZR-1 Net Registry Forums

Z51JEFF · 03-19-2010

How many have done this?

Throttle Body Heat Bypass Line by Marc Haibeck

Possible reasons to bypass the throttle body?

1) Much "stuff" is under the plenum (starter, A/C compressor, coils, etc). If bypassed, you don't have to fuss with draining coolant and refilling it (and getting the air out of the system). Bypassing, or even plugging the passages off entirely, eliminates both PIA parts associated with coolant draining. With an air ratchet, one can have the plenum off in about 5 minutes (if you leave the throttle lines connected), and on again in a few more (depending on condition of the gaskets). Fussing with coolant can easily add an hour to that process, has been my experience.

2) The plenum runs cooler which better for performance. Marc Haibeck has run his ZR-1 in the Chicago area for years and in sub freezing temperatures w/o any problem with icing.

3) Corrosion can be an issue with coolant running through the plenum.

bobbyhi · 03-19-2010

I have the by-pass and no problems. I don't have to worry about any leaks at the TB.

Aurora40 · 03-19-2010

One disadvantage is if you don't flare the ends of the bypass pipe, and the rubber line slips off and streams coolant under your plenum killing your starter. Ask me how I know about that one?

GOLDCYLON · 03-19-2010

I have, no issues on my DD in AZ heat either

Locobob · 03-19-2010

I bypassed both the throttle body and the entire plenum, no regrets. I did a write up on it for HOTB - last year I think?

A26B · 03-19-2010

Quote:

Originally Posted by Aurora40

One disadvantage is if you don't flare the ends of the bypass pipe, and the rubber line slips off and streams coolant under your plenum killing your starter. Ask me how I know about that one?

Yep! I didn't have the bypass though. The stock hose ruptured, facing towards the plenum (of course) & flooded the valley. Stuck in a gas station, fixed it, starter toast but easily push started (small miracle).

Lesson: don't forget the "little" coolant hoses when you replace the "big" ones.

Z51JEFF · 03-19-2010

Thanks for the replies.The reason I want to do this is to save the paint on the TB.

Z51JEFF · 03-27-2010

Anybody got some pictures of this mod?I broke out the tube cutter,bender,flaring tool and then ran into a wall.The plan was to make a hard line and run it under the front of the plenum keeping the coolant line intact,no room wont work.Next plan was to plug the line on both sides of the TB with the lines intact keeping the look stock.My question is the small line coming off the TB going back into the plenum,is this for a return back into the system only?Ive even thought about removing the TB plate and filling the cavity with epoxy to seal out the coolant,thats a bit drastic.

scholtmj · 03-27-2010

Quote:

Originally Posted by Z51JEFF

Anybody got some pictures of this mod?I broke out the tube cutter,bender,flaring tool and then ran into a wall.The plan was to make a hard line and run it under the front of the plenum keeping the coolant line intact,no room wont work.Next plan was to plug the line on both sides of the TB with the lines intact keeping the look stock.My question is the small line coming off the TB going back into the plenum,is this for a return back into the system only?Ive even thought about removing the TB plate and filling the cavity with epoxy to seal out the coolant,thats a bit drastic.

http://zr1specialist.com/HAT%20Web/p...t%20bypass.htm

Is this what you're looking for?

Z51JEFF · 03-28-2010

Quote:

Originally Posted by scholtmj

http://zr1specialist.com/HAT%20Web/p...t%20bypass.htm

Is this what you're looking for?

Thats it,I was all set to make one of these but couldnt see any room under the plenum.Now I know it can work Ill go take another look,Thanks for the link.

03-19-2010	#1
Z51JEFF Join Date: Dec 2007 Location: Fremont, CA Posts: 3,093	TB Coolant Crossover/Bypass, Any Disadvantages? How many have done this? Throttle Body Heat Bypass Line by Marc Haibeck Possible reasons to bypass the throttle body? 1) Much "stuff" is under the plenum (starter, A/C compressor, coils, etc). If bypassed, you don't have to fuss with draining coolant and refilling it (and getting the air out of the system). Bypassing, or even plugging the passages off entirely, eliminates both PIA parts associated with coolant draining. With an air ratchet, one can have the plenum off in about 5 minutes (if you leave the throttle lines connected), and on again in a few more (depending on condition of the gaskets). Fussing with coolant can easily add an hour to that process, has been my experience. 2) The plenum runs cooler which better for performance. Marc Haibeck has run his ZR-1 in the Chicago area for years and in sub freezing temperatures w/o any problem with icing. 3) Corrosion can be an issue with coolant running through the plenum. Last edited by ZBrink; 01-25-2025 at 10:35 PM. Reason: edited for clarity

03-19-2010	#2
bobbyhi Join Date: Jul 2005 Location: Mendota Heights, MN. 55120 Posts: 983	Re: TB coolant crossover,any disadvantages? I have the by-pass and no problems. I don't have to worry about any leaks at the TB.

03-19-2010	#3
Aurora40 Join Date: May 2005 Location: Leesburg, VA Posts: 2,704	Re: TB coolant crossover,any disadvantages? One disadvantage is if you don't flare the ends of the bypass pipe, and the rubber line slips off and streams coolant under your plenum killing your starter. Ask me how I know about that one?

03-19-2010	#4
GOLDCYLON Join Date: May 2007 Location: Peoria, AZ Posts: 9,119	Re: TB coolant crossover,any disadvantages? I have, no issues on my DD in AZ heat either __________________ GOLDCYLON - 91 ZR-1 #2014 GOLDCYLON - 90 ZR-1 #2794, 4L60e (Formerly Schrade's) GOLDCYLON - 11 CTS-V Arizona State Director 91 WHITE/BLACK #2014. 380 P&P&PCed,Ported Heads, Jeal Long tubes, Corsa Exhaust/FIKSE FM-5s /LED TLs, LED Headlights, Front Wilwood 6 piston narrowlite calipers and rear Wilwood caliper street shop mod,CNCed Coolant Pipes,TPI Cvr,Filter cover,Stainless Bolts, DRM/DOM PROM /ZFDOC mod build #102,DRLs,BMAD with stainless Debris Screen,Coplan Air Blaster, Pioneer APP Radio 4,Brey-Krause HB,Sub Bar,Fire extinguisher seat mount,DRM Coilovers,LEDs everywhere,Compass mirror (orange),V1 DIC hidden display, Homelink sun visor, Carbon Fiber top x3 and APSIS Carbon Fiber interior, APSIS CF Steering Wheel/NAPA Leather, Banski trailing arms, Guldstrand front suspension,urethane bushings from Prothane (total suspension) ZFDoc drive shaft safety loop, raptor shift light (orange),AO engineering louver front plate, Console seat cushion, 96CE seats with black custom Sheepskins, ss billet catch can,Viper remote entry/alarm,Cragar Rear Louvers,LED side louver lights, Dewitts Radiator with SPAL fans and a Woods 160 T-Stat 90 RED/BLACK #2794. 4L60e Automatic Stage V by RPM Transmission, TCI Dedicated TCM, OBX Stainless Headers, Corsa Exhaust, SAN Secondaries and Haibeck PROM, Exotic Muscle Coil overs, LED Interior Lights, LED Tail Lights, LED Headlights, 94 Sport seats with black custom Sheepskins , Cragar rear louvers, GS Front calipers, Banski Trailing arms, APSIS Carbon Fiber steering wheel, Front and Rear Baer Eradispeeds, DRLs, Guldstrand front suspension,urethane bushings from Prothane (total suspension), Dewitt's Raditor with Dual SPAL fans and a Haibeck 170 T-Stat 11 RED/GREY CTS-V

03-19-2010	#5
Locobob Join Date: Jan 2004 Location: Portland, OR Posts: 1,047	Re: TB coolant crossover,any disadvantages? I bypassed both the throttle body and the entire plenum, no regrets. I did a write up on it for HOTB - last year I think? __________________ Robert ZR-1 Net Registry Oregon State Director 91 ZR-1 #431 Black/Black LPE 368

03-27-2010	#8
Z51JEFF Join Date: Dec 2007 Location: Fremont, CA Posts: 3,093	Re: TB coolant crossover,any disadvantages? Anybody got some pictures of this mod?I broke out the tube cutter,bender,flaring tool and then ran into a wall.The plan was to make a hard line and run it under the front of the plenum keeping the coolant line intact,no room wont work.Next plan was to plug the line on both sides of the TB with the lines intact keeping the look stock.My question is the small line coming off the TB going back into the plenum,is this for a return back into the system only?Ive even thought about removing the TB plate and filling the cavity with epoxy to seal out the coolant,thats a bit drastic.