boost v octane whats safe

[rtviper]

Turbo v8 guys,how do you determine a safe boost at the track without a knock detector, for different octane gas?

If you know what HP you make on an engine dyno, and your not set up with a knock detector how do you come to know what's safe?

Can one assume 10 lbs is safe on 90 octane or 100 octane, and anything 15 lbs and over requires 116 octane.

Why spend 14 bucks a gallon if your not going to use maximum HP on runs.

will a dyno run in street trim tell you what's safe?

Do any of you Turbo V8 guys run 92 or 100 octane at the track?

 

[Louie L.]

Turbo v8 guys,how do you determine a safe boost at the track without a knock detector, for different octane gas?

If you know what HP you make on an engine dyno, and your not set up with a knock detector how do you come to know what's safe?

Can one assume 10 lbs is safe on 90 octane or 100 octane, and anything 15 lbs and over requires 116 octane.

Why spend 14 bucks a gallon if your not going to use maximum HP on runs.

will a dyno run in street trim tell you what's safe?

Do any of you Turbo V8 guys run 92 or 100 octane at the track?

I have only the knowledge that I have gathered from the Buick world and would use that to determine what is safe. I know that my motor made just over 800HP to the wheels @ 16-17 PSI. I would think that would be plenty safe on pump gas? It could possibly made more on pump gas due to the low timing.

 

[rtviper]

Thanks Louie.
My car has a Motec and is currently set at a max of 17 lbs boost. The dyno sheets show 1050 at 17lbs but that's on Duttweilers engine Dyno so that's probably about 800 to the wheels.
At this time I only want to run a 10.0 so I am guessing about 10 lbs should do it. I will use 100 octane, I just didn't want to detonate the motor.

I will drive to the track and don't want to burn up 14 dollar a gallon gas if it's not necessary.

 

[Louie L.]

Thanks Louie.
My car has a Motec and is currently set at a max of 17 lbs boost. The dyno sheets show 1050 at 17lbs but that's on Duttweilers engine Dyno so that's probably about 800 to the wheels.
At this time I only want to run a 10.0 so I am guessing about 10 lbs should do it. I will use 100 octane, I just didn't want to detonate the motor.

I will drive to the track and don't want to burn up 14 dollar a gallon gas if it's not necessary.

I run Q-16 so i know what you mean . I think your plans are solid. But you have to take into account turbo efficiency and timing into your plans. @10 psi it may not make the power you need. Also what timing was used to make max power @ 17 psi?. With low boost you can run a healthy amount of timing which may not like pump or even 100 octane. Do you have dyno info @ different PSI?

 

[rtviper]

The car is a twin 66 BB setup and on engine dyno it shows 10.6 lbs boost is 773hp 700 tq at 5800 rpm no timing info though. This was on the way up to 17lbs boost, so it may have higher numbers at higher rpm if I hold it at 10.6 lbs?

When it hit 17 lbs it was 1035 hp and 780 tq, seems low on tq . Engine gained over 200 hp from 11 lbs boost to 17 lbs and only 80 lbs tq

 

[Louie L.]

The car is a twin 66 BB setup and on engine dyno it shows 10.6 lbs boost is 773hp 700 tq at 5800 rpm no timing info though. This was on the way up to 17lbs boost, so it may have higher numbers at higher rpm if I hold it at 10.6 lbs?

When it hit 17 lbs it was 1035 hp and 780 tq, seems low on tq . Engine gained over 200 hp from 11 lbs boost to 17 lbs and only 80 lbs tq

No doubt that is a strong motor. It is quite possible that as you suspect the power output will be there at that low PSI. But as the motor gets into high RPM it needs more air flow. So at the high RPM and 10 psi the power out put may not be where we think. Thats nothing to worry about as you can adjust for this by adding some boost.

Sounds like @ 15 psi you should have what you need with reserve for that 10 oh! even on pump gas. I looked thru my old time slips and my old early S2 combo (249 ci, GN1Rheads with a stock ported intake, PTE 70 Q TSM Turbo) went 10.28 @18 psi.

Can you look at the program in the Motec? You could at the timing tables and how much timing is being used at that section between 10 psi thru 17 psi.It would be very useful to know. Just my 02

 

[rtviper]

No doubt that is a strong motor. It is quite possible that as you suspect the power output will be there at that low PSI. But as the motor gets into high RPM it needs more air flow. So at the high RPM and 10 psi the power out put may not be where we think. Thats nothing to worry about as you can adjust for this by adding some boost.

Sounds like @ 15 psi you should have what you need with reserve for that 10 oh! even on pump gas. I looked thru my old time slips and my old early S2 combo (249 ci, GN1Rheads with a stock ported intake, PTE 70 Q TSM Turbo) went 10.28 @18 psi.

Can you look at the program in the Motec? You could at the timing tables and how much timing is being used at that section between 10 psi thru 17 psi.It would be very useful to know. Just my 02

I just downloaded a Motec program into my laptop I am going to try to get some readings. I know my old stage 2 car dynoed 596 at the wheels 21 lbs boost and ran 10.03 at 134 with much heavier car then this one

Louie I have asked a question before with no results, I don't see any O2 sensors on this setup, how does the Motec work without it ? Does it just run the settings in the program and if your below set RPM its rich and at set RPM its just right? There is no adjusting for a/f ratio I presume?

 

[Louie L.]

I just downloaded a Motec program into my laptop I am going to try to get some readings. I know my old stage 2 car dynoed 596 at the wheels 21 lbs boost and ran 10.03 at 134 with much heavier car then this one

Louie I have asked a question before with no results, I don't see any O2 sensors on this setup, how does the Motec work without it ? Does it just run the settings in the program and if your below set RPM its rich and at set RPM its just right? There is no adjusting for a/f ratio I presume?

I am not familiar with the Motecs. But If you do not have O2's I suspect that KD tuned with a Wideband on the engine dyno and delivered it to you tuned?

Just FYI the FAST units and BS units will also work with out 02's. That is as long as they know what AFR to command at a given load. With out an o2 you are giving up the ability for the ECM to adjust and make it a close loop system. This is what will save a motor when you have a fuel pump going bad or something of the sort.

 

[bison]

What compression ratio and heads? If under 9:1 and modern heads you should be plenty safe at 14-15psi with 100 octane and 22-23 degrees advance. Motec should have many channels that could read multiple O2 sensors as well as knock sensors. Id be sure to ask KD about octane requirements since he is responsible for the tune. Fwiw my stage 2 is about 10:1 and will require at least 100 octane even at 15-16 psi with low timing. I plan on running 30-32 on Q16.

 

[rtviper]

What compression ratio and heads? If under 9:1 and modern heads you should be plenty safe at 14-15psi with 100 octane and 22-23 degrees advance. Motec should have many channels that could read multiple O2 sensors as well as knock sensors. Id be sure to ask KD about octane requirements since he is responsible for the tune. Fwiw my stage 2 is about 10:1 and will require at least 100 octane even at 15-16 psi with low timing. I plan on running 30-32 on Q16.

Thanks, Heads are Brodix Trac 1 CR is only 7.68 with 390 cubes. I am trying to not bug KD too much. I asked him a while back about Octane and he just said use as much as you can get? He supposedly had this motor to approx. 1450 on his dyno, with I dont know how much boost. It is set right now at 17 lbs max and 7100 RPM. The dyno print out I have is only to 7100 RPM and 17lbs
When I asked him how much Octane I didnt tell him I was going to use low boost.

 

[Louie L.]

Thanks, Heads are Brodix Trac 1 CR is only 7.68 with 390 cubes. I am trying to not bug KD too much. I asked him a while back about Octane and he just said use as much as you can get? He supposedly had this motor to approx. 1450 on his dyno, with I dont know how much boost. It is set right now at 17 lbs max and 7100 RPM. The dyno print out I have is only to 7100 RPM and 17lbs
When I asked him how much Octane I didnt tell him I was going to use low boost.

Those are the same heads Im running. Are they ported or out of the box? Do you have any cam specs ?

 

[rtviper]

Those are the same heads Im running. Are they ported or out of the box? Do you have any cam specs ?

KD did the Cylinder head work and by the cost, quite a bit according to all the paperwork. I don't have a cam number and KD didnt remember it but the Comp cam is a 244/244 LC 113 Roller. Comp Cams couldn't give me much info with what I had. Cam lash is 18 int, 20 exh.
This is a similar setup to Chows except the Turbos fit under the hood in the same postion.
I just had the Hogan Intake polished and I am getting ready for a Pinks invite I have for August here in WA.

 

[Dusty Bradford]

I would say 15psi and 20* is safe on pump gas. 12 psi is definately safe. I had the same heads for a while, even on 17psi, it would run 128mph to the 1/8 mile.

 

[malibuick231]

Why dont you run a alky kit with it? You can get a Snow Performance kit for about $250. That is what I have on my car but I'm not making as much power as you are. I would think you could run 17psi and 20deg on pump gas. I run 18psi and 25deg on pump gas with no detonation with a CR of 7.8. Mine makes about 800hp to the crank. What I would like to know is how do the Evo guys run 30+psi and pump gas not to highjack your thread.

 

[rtviper]

Why dont you run a alky kit with it? You can get a Snow Performance kit for about $250. That is what I have on my car but I'm not making as much power as you are. I would think you could run 17psi and 20deg on pump gas. I run 18psi and 25deg on pump gas with no detonation with a CR of 7.8. Mine makes about 800hp to the crank. What I would like to know is how do the Evo guys run 30+psi and pump gas not to highjack your thread.

I dont really want to run 17lbs at this point as I dont have a license yet so 10.0s is fine. I am an old fart, an 10.0s was plenty quick in my stage 2 car.
If I can run low 10s on 10 to 12 lbs that works for now. I am aiming to run 10.0s at Pinks as it seems to be the most often picked ET bracket?

I just wanted to be sure I wouldnt hurt anything on 12 lbs or so on pump gas.
I plan on driving to the track run and drive home so would like to use 5 buck a gallon gas instead of 14 buck a gallon

After some seat time I will turn up the boost and use c16

 

[rtviper]

Radiator for V8 swap

For those who do some street driving, what radiator are you using. I drove mine for the first time and the temps climbed up to 230.
I have read all the info about the F body swap and bought one today. It is awful small compared to the 4 row stock unit in it now.
I know I have some issues with the front mount being over 4 inches thick so I am concerned the 1 row unit I just bought, may not be enough?
I have 2 side by side fans on the stock radiator and when I drive the car the temps just continue to climb and don't come down until I shut it off.

 

[malibuick231]

I would try a Lincoln Mark VIII fan and see if that works first. They flow about 4500cfm.

 

[rtviper]

I forgot to mention I dont have room for a puller, it has to be a pusher. Twin turbo front mount, has the pipe pretty close to the radiator as it goes to TB.