1.15 ar for towing

[gmduramax]

I’m not sure if a ported IHI is just that much better but I towed 10k lbs up a decent grade and I removed the regulator and just ran a line like factory to reduce boost. I am at sea level and egt never went over 1200 on a 100° day. I want to say total boost was 30psi and the big turbo was making 20psi of it. And I was using every bit of 500hp or so to maintain 80mph

 

[danzick]

trying to remember.... I think it was around 8 psi when total was around 30?

 

[danzick]

I’m not sure if a ported IHI is just that much better but I towed 10k lbs up a decent grade and I removed the regulator and just ran a line like factory to reduce boost. I am at sea level and egt never went over 1200 on a 100° day. I want to say total boost was 30psi and the big turbo was making 20psi of it. And I was using every bit of 500hp or so to maintain 80mph

thats insane. Under full throttle on my max effort tune making 600 plus whp I think its around 50-52 psi of boost and my s475 is only around 20 of it.

 

[Chevy1925]

trying to remember.... I think it was around 8 psi when total was around 30?

That puts the small turbo at 22psi like I was wanting you to shoot for. Under that, you are in a worse efficiency range of the small turbo and egt’s go up.

 

[danzick]

so its a good thing? I thought in order to calculate the valley charger psi you had to do a pressure ratio calculation to figure its boost without the help of the larger charger?

 

[Chevy1925]

thats insane. Under full throttle on my max effort tune making 600 plus whp I think its around 50-52 psi of boost and my s475 is only around 20 of it.

Yeah you should be letting the gate open and make the 475 drive more there.

This is where I was saying playing with the regulator to get it to open the gate so the stock turbo stays in its efficiency range and the rest of the pressure is made from the big turbo

 

[danzick]

ok! im following now. so with the gate closed off for towing im staying in the efficiency range since total boost and fuel is so low. If i leave the gate closed off for full throttle, I will put it out of its range when i increase the fuel a whole bunch and over speed the small charger since it cannot bypass the extra drive pressure.

 

[Chevy1925]

so its a good thing? I thought in order to calculate the valley charger psi you had to do a pressure ratio calculation to figure its boost without the help of the larger charger?

Na, that’s how you figure out efficiency ranges on turbo maps between turbos. You find the pressure ratios and plot them along with either VE or hp.

 

[Chevy1925]

ok! im following now. so with the gate closed off for towing im staying in the efficiency range since total boost and fuel is so low. If i leave the gate closed off for full throttle, I will put it out of its range when i increase the fuel a whole bunch and over speed the small charger since it cannot bypass the extra drive pressure.

Yup, so try cracking the regulator a 1/4 turn to 1/8 turn at a time so you keep the small turbo at the right boost and the waste gate starts to open to let the big turbo come in

 

[Chevy1925]

I’m not sure if a ported IHI is just that much better but I towed 10k lbs up a decent grade and I removed the regulator and just ran a line like factory to reduce boost. I am at sea level and egt never went over 1200 on a 100° day. I want to say total boost was 30psi and the big turbo was making 20psi of it. And I was using every bit of 500hp or so to maintain 80mph

In the 02? Surprised it wasn’t laggy. It didn’t like no regulator when I had it

 

[gmduramax]

In the 02? Surprised it wasn’t laggy. It didn’t like no regulator when I had it

its not as responsive, but once the small turbo makes a few psi it climbs quick

 

[TheBac]

It is very weird to read Anthony's posts talking about your old limo, James.

 

[Chevy1925]

its not as responsive, but once the small turbo makes a few psi it climbs quick

i guess when you drive large singles all the time, that still seems fast

It is very weird to read Anthony's posts talking about your old limo, James.

lol sometimes i have to remember that but hes using her as intended!!