Supra Forums banner

1 - 20 of 65 Posts
S

·
Guest
Joined
·
0 Posts
Discussion Starter #1
I have t61 .81ar on cast manifold with VPC afc2 set to about 11.5A/F at 18psi. Someone said that it's not safe to run more than 15psi for longer highway pulls; I’m talking about 170mph+, simply staying in it till 6th gear. I have always turned the boost down to 1bar as soon as I hit about 140mph because of that reason. But if I tuned the car for 11.5a/f at 18psi and than turn the boost down to 1 bar and running rich and the car looses a lot of HP. So what would you say is SAFE boost. Also my EGT shows about 750-800C max at 18psi pull. I also have FJO to monitor the A.F.

Thanks
 

·
Driver Down
Joined
·
1,991 Posts
Spanki said:
I have t61 .81ar on cast manifold with VPC afc2 set to about 11.5A/F at 18psi. Someone said that it's not safe to run more than 15psi for longer highway pulls; I’m talking about 170mph+, simply staying in it till 6th gear. I have always turned the boost down to 1bar as soon as I hit about 140mph because of that reason. But if I tuned the car for 11.5a/f at 18psi and than turn the boost down to 1 bar and running rich and the car looses a lot of HP. So what would you say is SAFE boost. Also my EGT shows about 750-800C max at 18psi pull. I also have FJO to monitor the A.F.

Thanks
Exhaust Gas Temp is much different that internal cylinder temp. On pump, it just isn't worth the risk, IMO. Want to do a 0-170+ pull? get some race gas ;) then you can boost away! ;)

Zylo.. the race gas nazi :D
 
S

·
Guest
Joined
·
0 Posts
Discussion Starter #3
Re: Re: What is my max safe boost for highway pulls 170mph +?

Zylo said:
Exhaust Gas Temp is much different that internal cylinder temp. On pump, it just isn't worth the risk, IMO. Want to do a 0-170+ pull? get some race gas ;) then you can boost away! ;)

Zylo.. the race gas nazi :D
So every time there is 911turbo or a SC C5 or a viper next time I shouldn't race because I have no race fuel? I don't like the idea of race fuel. I hit rev limiter in 6th gear before with 93octane racing GTS viper on 1bar, and everything was ok. But that was at 1bar and my a/f was 10.0 since I didn’t have AFC2 installed at the time, I still pulled him hard after 160mph. :) That being said, i want to be safe at pump fuel since that’s what I use everyday. I'm just too scared to run more than 1bar on these long pulls. It's true that race fuel will make everything much safer.
 

·
Driver Down
Joined
·
1,991 Posts
Re: Re: Re: What is my max safe boost for highway pulls 170mph +?

Spanki said:
So every time there is 911turbo or a SC C5 or a viper next time I shouldn't race because I have no race fuel? I don't like the idea of race fuel. I hit rev limiter in 6th gear before with 93octane racing GTS viper on 1bar, and everything was ok. But that was at 1bar and my a/f was 10.0 since I didn’t have AFC2 installed at the time, I still pulled him hard after 160mph. :) That being said, i want to be safe at pump fuel since that’s what I use everyday. I'm just too scared to run more than 1bar on these long pulls. It's true that race fuel will make everything much safer.
You should be fine with 18psi.. 17psi would be even safer. Just give the turbo time to cool down between blasts..

How about one of Anarkey's alky injection systems?

(damnit.. this is twice today.. I want commission, damnit! :lol: )
 
S

·
Guest
Joined
·
0 Posts
Discussion Starter #5
Re: Re: Re: Re: What is my max safe boost for highway pulls 170mph +?

Zylo said:
You should be fine with 18psi.. 17psi would be even safer. Just give the turbo time to cool down between blasts..

How about one of Anarkey's alky injection systems?

(damnit.. this is twice today.. I want commission, damnit! :lol: )
I already have it, not installed yet. :) Also "I should be safe doesn't do it for me" It's 2K for new SB:( This is why I need to know for 100% I guess water would keep everything cooler once I install the W/M kit.
 

·
www.ziptieracing.com
Joined
·
1,785 Posts
Re: Re: Re: Re: Re: What is my max safe boost for highway pulls 170mph +?

Spanki said:
I already have it, not installed yet. :) Also "I should be safe doesn't do it for me"
then you should pass on doing 170mph runs. On pump gas, on public roads...i think "should be safe" is rather optimistic. If you want more than "should be safe" use race gas.
 

·
Moderator
Joined
·
3,148 Posts
I run between 16 and 17 pounds with 93 octane on the roadcourse. I will hit over 140mph 21 times in 20 minutes with 7 of those over 160mph. I have found that at 11.8:1 my EGT's get a little high. I richen it up to about 11.2:1 and everything is fine.

Later, Steve
 
S

·
Guest
Joined
·
0 Posts
Discussion Starter #8
Re: Re: Re: Re: Re: Re: What is my max safe boost for highway pulls 170mph +?

turbomx5 said:
then you should pass on doing 170mph runs. On pump gas, on public roads...i think "should be safe" is rather optimistic. If you want more than "should be safe" use race gas.
I did few 170+ pulls before but only at like 4AM when the road was empty and straight, if that makes it any better. So you telling me that the supra is not capable of running these speed unless it's on race fuel? Maybe a Z06 would be better after all? I thought that the supra was the TOP dog for doing high speed pulls...
 
S

·
Guest
Joined
·
0 Posts
Discussion Starter #10
Steve Jarvis said:
I run between 16 and 17 pounds with 93 octane on the roadcourse. I will hit over 140mph 21 times in 20 minutes with 7 of those over 160mph. I have found that at 11.8:1 my EGT's get a little high. I richen it up to about 11.2:1 and everything is fine.

Later, Steve
What was your EGT at? And where is the probe located? Mine is right after AR.
 

·
Retired Super-Mod
Joined
·
10,170 Posts
EGT is dependant on AFR as I understand it. Therefore if you do what Steve says and keep your AFR in good shape you will be fine on whatever octane.
 

·
Registered
Joined
·
78 Posts
What costs more? A blown motor or 15 Gallons of C16 or C12?

If your a little short on the $...You can home brew your own race gas for cheap, just do a search and it tells you all the ratios.
 
M

·
Guest
Joined
·
0 Posts
Discussion Starter #14
Honestly I do not believe there is any safe way to be boosting at 170mph+ on pump gas, no matter how well tuned your car is, the risk of preigition is high. You will be burning pistons with the burn characteristics of 93 octane under those conditions.
 
K

·
Guest
Joined
·
0 Posts
Discussion Starter #15
Spanki said:
What was your EGT at? And where is the probe located? Mine is right after AR.
I would like to know too. I am running 16psi with conservative timing and the afr at 12.0. My egt is at the 6th runner (1 inch away from the head. My egt gets to 800C.

I just thought that my timing was too conservative but maybe I should richen it to 11.5? I am always tuning on the street and it is dead on 12.0 every single pull that I have done :)

Any thoughts?

Kaz
 

·
Registered
Joined
·
1,421 Posts
Like Zylo said, the alchohol injection will work. I was under the impression that it was actually better than race gas at preventing knock and keeping temps down in the combustion chamber. Just install the kit and you will be ready anytime for a good race.
 

·
Driver Down
Joined
·
1,991 Posts
VeilsideTT said:
Like Zylo said, the alchohol injection will work. I was under the impression that it was actually better than race gas at preventing knock and keeping temps down in the combustion chamber. Just install the kit and you will be ready anytime for a good race.
Any forced induction setup I own will have alky injection. Its expensive initial cost, but cheap in the long run. Great insurance against engine damage, and keeps the engine efficient and clean!

Alky injection is great stuff!

If I could justify the initial cost, i'd run it on my lil' 4.6L N/A :)
 

·
Moderator
Joined
·
3,148 Posts
I have seen as high as 790C at the top of the downpipe on a long session. :eek: When I richen up the A/F ration it drops to around 720C or less.

Later, Steve
 

·
Lets go Nets
Joined
·
2,956 Posts
hmm impressive, paul, you should lay off the 170 mph pulls, not too safe, and wouldn't want to blow an engine. just stop at 140, thats easy enough. maybe throw that alohocl injeciton in from Anarkey dude. just my $.02

Brett
 
A

·
Guest
Joined
·
0 Posts
Discussion Starter #20
Yeah, install the kit! It works ESPECIALLY well for long pulls, as the normal heat rise (pistons, eshaust valves, spark plug tips, oil, coolant, etc) just doesn't happen. All that heat goes out the tailpipe as steam, rather than staying in the motor.

I should note, if your intercooler is too small, THAT will still get heat soaked. Although at 140MPH, the airflow may be enough to make up for that somewhat.
 
1 - 20 of 65 Posts
Top