[toohighpsi]

I've made 729RWHP on an LT1 with the following modifications.

LT4 fuel system (109 octane unleaded)
Magnuson TVS2300 Heartbeat DI (13.8 psi boost)
103mm Nick Williams TB
Rotofab CAI
AEM Water/Meth 50/50
Dragradials and Skinnys

All else stock - including exhaust and catalysts

Car ran 9.93@140

Video below:
https://youtu.be/bdJz6CJALtU

[laynlo15]

I was running Vp Ms109 and 1000cc Nozzle of Meth/water and 25 degrees of timing. Running 10.00s@140 back then and oooppps broke a couple ring lands. Required new forged internals for this year.

[oldman]

Yep go with big injectors and LPE high pump and 38%cam lobe
Vs
Dual injection

IMO, you are wasting time with anything in between, unless you know you will stay near stock with 7 psi...

[Drsagacity]

Originally Posted by 95 imp

Stick.

Probably a procharger D1x

Ported heads, valves, exhaust (intake on a pro) and cam are all going to change boost psi. So, I'm asking for an apple to apple comparison, or as close as possible, to try and theoretically figure out where I need to be.

Fuel depends on the FCR. You can't force an engine to drink a fuel it doesn't like for very long. And it would be backwards to say I'm running 91 octane and want 800 hp. Only place I know that can make a combo like that work is Fantasy Motorsports. The fuel is what I trying to figure out. But I need to have a ballpark FCR. That means I need a ballpark psi. The volume vs octane tightrope, IMO, is what is killing these motors.


So, for example, (assuming a 2400 +/- elevation) you were running a FCR around 23/1. That needs hella octane to not detonate. Either in the gas, E, meth, or all 3. (For reference, a Duramax diesel is only 17.5/1)

What I trying to say is I want XXX hp and what do I need to make it happen within a particular engine. I do not want to just throw money and tears at it based on a guess.

Does it really matter what I own? Or what car I put a motor in? I thought this was a brotherhood type thing. I'm not trying to bust anyone's balls. Sorry if it comes across that way. I'm just trying to figure out the best way to hit my goals with what is available and I'm asking the peeps in the group to share some hard earned knowledge while I give some of mine and we all become better.

So, back to the topic.... Was the 750 @ 16.5 bone stock except for lt4 fueling? What octane fuel?

I added cam, forged pistons, LT4 fuel, voltage booster, headers and e85. I think 750whp was in the 10-11psi range. I know 775whp was 12psi.

[Choda]

cam with fuel lobe on factory fuel system
factory engine
93 with 3 nozzle meth
10-11 psi single turbo
A8
750 wheel

[95 imp]

Thanks for the info guys!

Originally Posted by toohighpsi

LT4 fuel system (109 octane unleaded)
Magnuson TVS2300 Heartbeat DI (13.8 psi boost)
AEM Water/Meth 50/50

Sounds like you have it dialed in! On the data logs running the 109, does it pull timing on occasion? Or, did you go easy on it in the tables? What is your race weight?

I watched the vid and seen you run at Famoso. At that elevation, you're FCR is around 22.5/1

Laynlo- You're under 1k too. According to the chart, you were around 24.5/1 at the time of the "accident" LOL

Do you have any pics of the dead slugs and cylinders? I'd like to compare them to the ones in another thread.

Here is the chart I am using if anyone is curious.

http://goodvibesracing.com/Compression_Ratio.htm

It has formulas for corrected CR as well as FCR. The corrected ratio should be 100% accurate. The boosted ratio is probably not so much since, like everyone was saying, the same blower and pulley setup can yield different psi.


Also, for those blending fuels, here is a cool octane calculator. Plug in the gallon price and it will calculate how much a tank of gas costs too!

www.serioussolutions.com/evo/octcalc.htm

* It will not work with alcohol blends. According to Sunoco, gas/alcohol blends aren't linear.

https://www.sunocoracefuels.com/tech...hol-and-octane

[95 imp]

Originally Posted by Drsagacity

I added cam, forged pistons, LT4 fuel, voltage booster, headers and e85. I think 750whp was in the 10-11psi range. I know 775whp was 12psi.

Did you wipe the stock pistons out? Or did you just go straight to the forged set?

Originally Posted by Choda

cam with fuel lobe on factory fuel system
factory engine

Didn't you pop your stock motor? Do you have any piston porn (pics of damaged pistons/cylinder walls) you could share?

[parish8]

I like doing the math.

Take your na hp and divide by 14.5, this is pretty close to how much hp you should gain per psi of boost. It is a good gauge to see how well your set up is working.

400hp na, 400/14.5=27.6hp/psi. To get 350 more hp would require 350/27.6 = 12.7 psi.

This is rough but usually pretty close. Maybe a little higher for a turbo and a little lower for a blower. Seems like the first few psi are higher, the it is consistent for awhile. Then at some point your compressor runs out and the hp per psi drops off hard.

[95 imp]

Originally Posted by parish8

I like doing the math.

THIS!

I HATE math. Absolutely hate it. But, I have learned over time you can rule the world if you have the right equation(s). I wish I would of learned this fact in high school and had a nicer algebra teacher!

Thanks!

As a side note, would it be a little more accurate @ 14.7 since that is the weight of air @ sea level?

[Umbriel]

Originally Posted by parish8

I like doing the math.

Take your na hp and divide by 14.5, this is pretty close to how much hp you should gain per psi of boost. It is a good gauge to see how well your set up is working.

400hp na, 400/14.5=27.6hp/psi. To get 350 more hp would require 350/27.6 = 12.7 psi.

This is rough but usually pretty close. Maybe a little higher for a turbo and a little lower for a blower. Seems like the first few psi are higher, the it is consistent for awhile. Then at some point your compressor runs out and the hp per psi drops off hard.

I just did the math for mine using rwhp and it is saying that I am trying to add 406 rwhp with my setup. No wonder I am having fueling issues, lol.

Sent from my SM-G955U using Tapatalk

[parish8]

Originally Posted by 95 imp

As a side note, would it be a little more accurate @ 14.7 since that is the weight of air @ sea level?

I am not sure how that works. 1 bar = 100 kpa = 14.5psi. Sounds like average pressure at sea level is slightly more than one bar. Who came up with that silliness?

You could take it one step further and get a kpa reading when you do your na dyno runs. Let’s say you are at 400hp at 96kpa(13.92psi) that would be 400/13.92 = 28.73 hp per psi of boost over 96kpa.

It gets a little complicated but if you use the cars map sensor for all the calcs it helps. To keep it simple I just assume 100kpa na which is not correct and probably why I get a little more power than expected for the first couple psi of boost.

[oldman]

Or just take the hp the engine would be making NA and add 7% for each psi. 400 hp bout 28 hp. Probably 8% for a turbo

[95 imp]

Originally Posted by oldman

Or just take the hp the engine would be making NA and add 7% for each psi. 400 hp bout 28 hp. Probably 8% for a turbo

That works out about the same as the other formula. Thanks!

[Drsagacity]

Originally Posted by 95 imp

Did you wipe the stock pistons out? Or did you just go straight to the forged?

I went straight to the forged setup. I prefer to go safe early. I am doing the the same thing on my Vette.

I did choose to push it on previous blower builds and found out that it can be much more cost effective to simply do it right up front. With my previous build when the piston cracked it lodged in the cylinder and I ended up with a cracked block...replaced engine with entirely new forged motor...I would prefer to skip that experience with my current cars.

My Camaro with the Maggie will run 700-775whp in pump e...8-12psi. If I want to run race fuel I think I could run 800whp safely.

My Vette has the LT4 blower with the same setup as the Camaro...except that I have Ted’s smooth idle cam. That car will be 650-700whp and done.