[TransAm 474]

Also Tom, what is your opinion on a safe timing for 16-18 psi with the 110 octane? I know you cant give me an exact number, but I'm just looking for a ball park estimate that this combination would be safe with. It will be a blow-through EFI TBI setup(Fitech 1200 PA) Non-Intercooled at this point.

[Tom Vaught]

I tell people like Charlie66 to stay under 27 degrees of total timing.
He has never hurt anything with that suggestion due to combustion issues.

But he took baby steps to get there. I would start out at 22 degrees and learn how to read plugs as well as having a a good Air/fuel meter system initially. Just because you are at lower boost DOES NOT mean that the timing is wrong. Make the power with boost, not timing.
Stay below 27 degrees and you will have an engine that will live a long time and when you turn the boost up it will continue to live.

A bad decision in timing has hurt more boosted engines than any basic failure of parts.

Tom V.

[TransAm 474]

Originally Posted by Tom Vaught

I tell people like Charlie66 to stay under 27 degrees of total timing.
He has never hurt anything with that suggestion due to combustion issues.

But he took baby steps to get there. I would start out at 22 degrees and learn how to read plugs as well as having a a good Air/fuel meter system initially. Just because you are at lower boost DOES NOT mean that the timing is wrong. Make the power with boost, not timing.
Stay below 27 degrees and you will have an engine that will live a long time and when you turn the boost up it will continue to live.

A bad decision in timing has hurt more boosted engines than any basic failure of parts.

Tom V.

Very Valuable information Tom, Thank You, I appreciate it. I think it would probably be safe to start out pulling 1.2° per lb on the street with pump gas, so it would pull it down to 24° total under 10 psi of boost(36° locked initial). I think it would probably be safe to just pull .8° per lb with the 110 octane fuel at the track, so it would pull it down to 21.5° total under 18 psi of boost to start with. Now, I know this is Non-Intercooled, atleast at this point, but I'm thinking I will have somewhat of a cooling effect to help out, since It will be a blowthrough TBI setup, the intake will still be wet, unlike port injection. Atleast that is the theory with most blowthrough carb applications, most people say an intercooler is really not needed, but I'm sure it could make more power with one, but sometimes its hard to package in a street car.

[charlie66]

JMO , If i was not using a cooler ( which i would never do) i would be REAL conservative with the timing...

[Tom Vaught]

The air is so hot coming from the turbo, even at low boost levels, that 10-12 psi could be 150 degrees hotter combustion charge temp vs ambient temp easily. 230 degrees with no cooler is a very hot charge temperature and really promotes combustion issues.
That is why some like 70 Bird install a Snow Water Injection system before the throttle body or carb. You want to be in the 120 - 140 charge temp range, not 250+ range.

Tom V.

[TransAm 474]

Hmmmm... I appreciate the help and guidance... I may want to look into a water/meth injection system then. Might even be able to stick with my 9-1 compression with the water injection from what I'm reading? It really sounds like a great thing to do to be on the safe side, and a potential significant increase in power.

[TransAm 474]

I just got off the phone with dad, and I had forgotten about a Treadstone Air-Air Intercooler that he had left over from his D1SC Procharger car, it is like brand new, so maybe I will just use it instead of the water injection, since I already have access to it. Here are sone features of it...


TRV25 Series Intercooler 1000HP
Tweet Treadstone Intercooler features superb quality highly efficient bar and plate construction. These intercoolers are perfect for any car making some serious horsepower; Supras, Mustangs, Nissans, Grand Nationals...etc. This intercooler is 3.50" thick, and will easily support 1492 CFM's 1000HP at max efficiency 1.5psi pressure drop. 1-Year Warranty. Intercooler will come with no logo, "Treadstone" logo can be requested in Blue, Black, or Red.
Overall Size 26.50" X 12.00" X 3.50"
Core Size 25.00" X 6.00" X 3.50"
3.00" Inlet/Outlet
1000 Hp efficient
Mounting tabs for easy installation

[charlie66]

In regards to timing, theres also a cliff that you want to stay away from on the low side as well. Maybe you knew this already but i just figured id throw it out there just in case . I have a good story on that one . Thank god i learned from a friend and not and not on my own turbo..

[charlie66]

Thats the exact cooler i have.

[TransAm 474]

Originally Posted by charlie66

In regards to timing, theres also a cliff that you want to stay away from on the low side as well. Maybe you knew this already but i just figured id throw it out there just in case . I have a good story on that one . Thank god i learned from a friend and not and not on my own turbo..

I have indeed heard that in the past, I just wasnt sure of how low you can go without going over the cliff. Ive heard of people pulling too much timing, and combined with too much fuel, it can lift the ring lands.

Originally Posted by charlie66

Thats the exact cooler i have.

Thats awesome! How do you like this cooler? Do you just run the cooler, or do you run water injection along with it? What IAT are you seeing with it? I appreciate the help

[charlie66]

Well every engine will differ. Its just a matter of knowing your air temps in your manifold not your intercooler pipes, AFR and most importantly reading your plugs. If all those are in check then you can play with your timing to see what gains you can get . Its not always what your buddy or what you read on line will be for you. You have to find what your combo wants with the giuld lines of what your being told will work.. And its not only burning your pistons that low timing can do. Low timing can burn the tips of your turbin wheel fins right off. Basically ruin your turbo ..

As for my cooler, its good , but anything over 1100 hp id be looking for a better one.. My temps vary with the weather. In warm weather its always operating at the ambient temperature. So if its 80 degrees out thats what i have at idle in the manifold. It will rise from there as i make a run. But if theres more boost involved then at the end of a pass it will be higher. So say i make a run and it 80 degrees out with 28psi ( thats my everyday setting ) by the end of the run the temp with be like 140 . But if i had 34 psi ( my second setting i use ) I ll have 156 - 160 ish.. I use E85 just so you know.. and no , i dont use water injection. I thought about trying it but never got around to it. Always something that happens that needs fixing that keeps me from trying it. High boost is high maintenance . My high setting right now is 44 psi.. If this deal im looking to get comes though ill be stepping up to 50 psi ..

[TransAm 474]

Originally Posted by charlie66

Well every engine will differ. Its just a matter of knowing your air temps in your manifold not your intercooler pipes, AFR and most importantly reading your plugs. If all those are in check then you can play with your timing to see what gains you can get . Its not always what your buddy or what you read on line will be for you. You have to find what your combo wants with the giuld lines of what your being told will work.. And its not only burning your pistons that low timing can do. Low timing can burn the tips of your turbin wheel fins right off. Basically ruin your turbo ..

As for my cooler, its good , but anything over 1100 hp id be looking for a better one.. My temps vary with the weather. In warm weather its always operating at the ambient temperature. So if its 80 degrees out thats what i have at idle in the manifold. It will rise from there as i make a run. But if theres more boost involved then at the end of a pass it will be higher. So say i make a run and it 80 degrees out with 28psi ( thats my everyday setting ) by the end of the run the temp with be like 140 . But if i had 34 psi ( my second setting i use ) I ll have 156 - 160 ish.. I use E85 just so you know.. and no , i dont use water injection. I thought about trying it but never got around to it. Always something that happens that needs fixing that keeps me from trying it. High boost is high maintenance . My high setting right now is 44 psi.. If this deal im looking to get comes though ill be stepping up to 50 psi ..

Wow, you are running alot of boost! Lol... The most I will ever run, atleast on this engine, is 16-18 psi, and that would be with 110 octane, but 90% of the time it will be running down at 10-12 psi and 91 octane pump gas. Thank You for sharing your knowledge Charlie, it helps a bunch.

[Tom Vaught]

Originally Posted by charlie66

Well every engine will differ. You have to find what your combo wants with the guide lines of what your being told will work.. And its not only burning your pistons that low timing can do. Low timing can burn the tips of your turbin wheel fins right off. Basically ruin your turbo .. ..

Like I said you can really screw up the combustion process (high heat) with the wrong timing, and those very hot combustion gases have to pass thru the turbine wheel to get to atmosphere. It is very possible to generate enough heat to melt the tips on the Turbine Wheel. No BS on that statement.

Tom V.

[charlie66]

Originally Posted by TransAm 474

Wow, you are running alot of boost! Lol... The most I will ever run, atleast on this engine, is 16-18 psi, and that would be with 110 octane, but 90% of the time it will be running down at 10-12 psi and 91 octane pump gas. Thank You for sharing your knowledge Charlie, it helps a bunch.

At your boost level You wont have much of a challenge. But that dosent mean you dont have to be real careful either.Since you're not using e85 and even though you're going to use 110 octane at the higher levels ,if it was me id plumb in Meth injection. I have a few friends that use it and it really does work well , and gas dont cool like e85. Being you're a street guy the car can get heat soaked. so the meth will really help you out.. All i can say is dont get too cocky with the timing . You want your plug strap to have the heat ring just right before the bend. I have mine mid way because id rather be down alittle on power then be on the edge with the timing.. Same with low timing . Just find the middle and maybe go 1 or 2 degrees past that and call it good.. For me 25-26 is the highest . There is a point as you reach the edge you will find that there really isn't enough gain of power to justify the risk in going higher . Its sort of like a spectrum of power, From low to high you will find your biggest gains will be as you move up from you low point. As you continue the gains start to diminish to where its not worth the 10hp you gain from it . If you want more power at that point raise the boost ..

[charlie66]

Originally Posted by Tom Vaught

Like I said you can really screw up the combustion process (high heat) with the wrong timing, and those very hot combustion gases have to pass thru the turbine wheel to get to atmosphere. It is very possible to generate enough heat to melt the tips on the Turbine Wheel. No BS on that statement.

Tom V.

Ive seen it first hand . lol

A friend of mine did it..

Burnt about 3/8" off all of them ..

But he was only running 10 degrees .. He was scared. Look where that got him . lol

Hes at 18 degrees now . It wasnt a Pontiac ...

[charlie66]

One thing i might add is , When i was at the dyno with my friend ( chassis dyno) he gained 100hp adding 8 degrees . He was at 10 degrees from start and 18 degrees when done . Anything after that was minimal . Think he went to 23 dgrees and made 10 more hp . At that point the motor was done so he backed to 18 to be safe.. So thats why going to the edge IMO is not woth it..

[Tom Vaught]

Don't ever say to a dyno operator, "can you give me a few more HP from where we are".
When you say that you take the liability off of him and it is all on you.
Now if he kills a head gasket or torches a piston/valve, it is on you to fix it.

Lots of good Dyno Guys out there, Ken Duttweiler being one of the best in the game, and I never saw a more conservative Dyno Guy. He knows how to make them live for 5 miles on a Bonneville Salt Flats run and still take the record for the fastest 4 wheel vehicle (not a Jet) that ever ran on the salt. We are talking 460+ mph runs.

Timing is dangerous because many do not understand how destructive it can be with too little or too much timing for a given engine. Also manually VERIFY that the harmonic Balancer is accurate as far as your timing assumptions.

Tom V.

[wreckmastr]

Originally Posted by Tom Vaught

Timing is dangerous because many do not understand how destructive it can be with too little or too much timing for a given engine. Also manually VERIFY that the harmonic Balancer is accurate as far as your timing assumptions.

Tom V.

^^^^^ Exactly^^^^^

Plus may I add there is NO SUBSTITUTE for reading the plugs. When it comes to timing (or fuel) don't trust anything but the plugs. The motor will tell you what makes it happy. Makes small changes at a time and pay attention.
Just my 2 cents

[charlie66]

Originally Posted by Tom Vaught

Don't ever say to a dyno operator, "can you give me a few more HP from where we are".
When you say that you take the liability off of him and it is all on you.
Now if he kills a head gasket or torches a piston/valve, it is on you to fix it.

Lots of good Dyno Guys out there, Ken Duttweiler being one of the best in the game, and I never saw a more conservative Dyno Guy. He knows how to make them live for 5 miles on a Bonneville Salt Flats run and still take the record for the fastest 4 wheel vehicle (not a Jet) that ever ran on the salt. We are talking 460+ mph runs.

Timing is dangerous because many do not understand how destructive it can be with too little or too much timing for a given engine. Also manually VERIFY that the harmonic Balancer is accurate as far as your timing assumptions.

Tom V.

The good thing about my dyno guy is he runs the car and i make the changes between runs..

[RAIV-Z]

Water to air intercooler intake air temp datalog for ~19lb boost.