I Need Advice!

[kharless]

I recently had my motor rebuilt by my local Mack dealer. My boost gauge shows 17 psi maximum. Allentown Mack said this is good as well as my local Mack dealer. However, a good friend of mine who has been running Macks successfully for 30+ years has told me that I should boost 23 psi minimum. Who is correct here? My turbo is new.

[theakerstwo]

I recently had my motor rebuilt by my local Mack dealer. My boost gauge shows 17 psi maximum. Allentown Mack said this is good as well as my local Mack dealer. However, a good friend of mine who has been running Macks successfully for 30+ years has told me that I should boost 23 psi minimum. Who is correct here? My turbo is new.

Hi I am a long time truck mechanic and I have found out that if you ask enough people that same thing you will hear what you think is real or what you want to hear.There are alot of factors in this question and you will have to find out what model engine what turbo and is it still set to specs and then some one out here can look it up in a mack tune up book and tell you.So many people have set the fuel up on their pumps and you know that any one that has overhauled your engine is not going to set the fuel up and put warranty on it at the same time. And I know that there is truck drivers out ther that will not agree with me. my 2 cents worth

Glenn Akers

I recently had my motor rebuilt by my local Mack dealer. My boost gauge shows 17 psi maximum. Allentown Mack said this is good as well as my local Mack dealer. However, a good friend of mine who has been running Macks successfully for 30+ years has told me that I should boost 23 psi minimum. Who is correct here? My turbo is new.

I forgot to tell you that I have a 315 hp with a air /air cooler on the front that will build 30psi but it would not dothat all day under a load without a burnt piston but I have set the fuel up on it. Glenn Akers

[kharless]

Hi I am a long time truck mechanic and I have found out that if you ask enough people that same thing you will hear what you think is real or what you want to hear.There are alot of factors in this question and you will have to find out what model engine what turbo and is it still set to specs and then some one out here can look it up in a mack tune up book and tell you.So many people have set the fuel up on their pumps and you know that any one that has overhauled your engine is not going to set the fuel up and put warranty on it at the same time. And I know that there is truck drivers out ther that will not agree with me. my 2 cents worth

Glenn Akers

I forgot to tell you that I have a 315 hp with a air /air cooler on the front that will build 30psi but it would not dothat all day under a load without a burnt piston but I have set the fuel up on it. Glenn Akers

Thanks for the replies Glen. So, should I just leave it alone until after the warranty? I guess my question really is what can my motor take and still give me 5 years or more? Here in West Virginia a person can get some conflicting advice from old coal haulers as compared to the dealer.

[greg]

My 300 which has about 180,000 on it has a boost of about 18psi. My advice is I would leave it alone. No sense in burning anything up in a newly rebuilt engine, especially if they won't warranty it if it's been turned up. Just my opinion.

Greg

[kharless]

My 300 which has about 180,000 on it has a boost of about 18psi. My advice is I would leave it alone. No sense in burning anything up in a newly rebuilt engine, especially if they won't warranty it if it's been turned up. Just my opinion.

Greg

Thanks guys for the advice. I think that I will leave everything alone and be happy with it. At first I thought that I had a boost leak around a hose. Someone told me that if I hear a whistle it is'nt the turbo but a leak in the air system. I have always used cummins and am new to Mack, so I am not sure.

[Lmackattack]

My 285 tip turbine was pushing 15-16 psi before I messed with the fuel. With the fuel turned up I see about 17-18 psi (19-20 psi in the cold winter months) Like Glenn said I can mash the pedal thru all 5 gears but the EGTs do get a little high. Im from the midwest so hills are far and few between. There are many diffrent turbo specs and they all may produce slightly diffrent boost levels.

Trent

[terry]

My 285 tip turbine was pushing 15-16 psi before I messed with the fuel. With the fuel turned up I see about 17-18 psi (19-20 psi in the cold winter months) Like Glenn said I can mash the pedal thru all 5 gears but the EGTs do get a little high. Im from the midwest so hills are far and few between. There are many diffrent turbo specs and they all may produce slightly diffrent boost levels.

Trent

My 285 hp with the tip turbine will put out 25 to 28 lbs. on a good pull, Will a stock engine pull that much boost? or has it been turned up? I always thought it was hard on fuel? Terry

[HK Trucking]

For whatever it's worth, my 91 RB 688s with a E7 400 is equipped with a factory installed boost guage & runs 35 lbs boost on a hard pull in cool weather, tapers off to about 32 lbs on a hot summer day. Don't have the boost spec handy for that particular setup, maybe Superdog would know.

[b61mack]

I recently had my motor rebuilt by my local Mack dealer. My boost gauge shows 17 psi maximum. Allentown Mack said this is good as well as my local Mack dealer. However, a good friend of mine who has been running Macks successfully for 30+ years has told me that I should boost 23 psi minimum. Who is correct here? My turbo is new.

I have a 1988 Mack engine tune-up specifications manual, it said intake boost pressure @ rated speed is 15-23 psi for E6-300 4VH, the E6-350 4VH is 20-28 psi