Whats the maximum boost you can run on pump gas?
Whats the maximum boost you can run on pump gas? what kind of things do you take into consideration?
assuming it will be:
built 408 motor
forged pistons
8:5-9:1 CR
gt55 turbo
griffen intercooler
rc 75# injectors
91 octane(its all the crap we have out here besides 101 race fuel)
any ideas?
assuming it will be:
built 408 motor
forged pistons
8:5-9:1 CR
gt55 turbo
griffen intercooler
rc 75# injectors
91 octane(its all the crap we have out here besides 101 race fuel)
any ideas?
TECH Enthusiast
Joined: Nov 2003
Posts: 689
Likes: 0
A GT55? At 14 psi you should be making over 900 RWHP on a 408. We had a friends car on the dyno this summer, it's a 321" SBF fed by a 91.5MM turbo, at 21 psi it made 1040-odd RWHP, and at 14 psi on pump gas it made about 815 RWHP, through a turbo 400. On 8.5:1 you should be able to run atleast 14 psi safely, although you're probably going to want to turn it down for most street driving.
Teching In
Joined: Sep 2004
Posts: 36
Likes: 0
many many variables...
it also depends on hpw much timing you want to run at full boost...
here's some more variables that will determine detonation points...
- precision and degree of engine management control?
- knock sensors?
- piston and head design?
- coatings?
- water/methanol injection?
- quench?
- cam profile / intensity (affects cylinder pressure)
to name just a few.
8.5:1 could run from 14lb to 20lb on pump gas depending on many things... also 14lb at 30 degrees timing is worth more power than 18lb at 18 degrees timing... etc
Unless you have a big budget - playing safe is always best as going for that killer tune/big number often leads to tears not long afterwards, whereas a little more conservative cangive you years of pleasure.
I ran 18psi on 91 octane at a true 9:1 with 24 degrees timing at full boost in my daily driver with Aquamist water injection and coatings. That was a conservative tune, but without water it would have blown up very quickly.
If you mirror the head chamber in the piston dish and run a tight quench, you'll be able to run more boost on any octane (esp. with coatings) than with the normal combos - but it requires custom pistons and the piston manufacturer (I'd use CP) need a head to work off. It's also worth very good power gains... that's an insider secret
that's not always within budget - but the least you should do is a good bore/hone job with honing plates, a good ring job, and a balance.... that way you stand more chance of sealing whatever you run.
Good luck
it also depends on hpw much timing you want to run at full boost...
here's some more variables that will determine detonation points...
- precision and degree of engine management control?
- knock sensors?
- piston and head design?
- coatings?
- water/methanol injection?
- quench?
- cam profile / intensity (affects cylinder pressure)
to name just a few.
8.5:1 could run from 14lb to 20lb on pump gas depending on many things... also 14lb at 30 degrees timing is worth more power than 18lb at 18 degrees timing... etc
Unless you have a big budget - playing safe is always best as going for that killer tune/big number often leads to tears not long afterwards, whereas a little more conservative cangive you years of pleasure.
I ran 18psi on 91 octane at a true 9:1 with 24 degrees timing at full boost in my daily driver with Aquamist water injection and coatings. That was a conservative tune, but without water it would have blown up very quickly.
If you mirror the head chamber in the piston dish and run a tight quench, you'll be able to run more boost on any octane (esp. with coatings) than with the normal combos - but it requires custom pistons and the piston manufacturer (I'd use CP) need a head to work off. It's also worth very good power gains... that's an insider secret
that's not always within budget - but the least you should do is a good bore/hone job with honing plates, a good ring job, and a balance.... that way you stand more chance of sealing whatever you run.
Good luck
thank you for all the advice. i have stage 3 hand ported afr heads that will be on the motor, so i seriously have not spared any expense. i will only be able to run 91 oct.
is it concievable to have more then 700 rwhp on pump gas with this setup?
is it concievable to have more then 700 rwhp on pump gas with this setup?
TECH Enthusiast
Joined: Nov 2003
Posts: 689
Likes: 0
Originally Posted by 2000 Tran Zam
thank you for all the advice. i have stage 3 hand ported afr heads that will be on the motor, so i seriously have not spared any expense. i will only be able to run 91 oct.
is it concievable to have more then 700 rwhp on pump gas with this setup?
is it concievable to have more then 700 rwhp on pump gas with this setup?
That 321" motor I told you about was nothing exotic. Off the shelf heads, off the shelf intake, and a small 236/232 cam. On the engine dyno it made 463 horsepower. Never dynoed it in the car naturally aspirated, but we figured it would make around 380 through the T400. You're building a motor that should outdo this one by atleast 100 RWHP naturally aspirated, and you're going to be running a larger turbo. 700 RWHP will be cakewalk for this setup, trust me. Remember that C5 last year, made over 1000 RWHP at 13 pounds of boost? That was a 408, 8.5:1 compression, and twin T66's. Twin T66's and the turbo you're going to run are in the same ballpark in terms of horsepower potential, if that gives you any idea of what kind of power you can make.
700rwhp on 91 perhaps, but I doubt that I would want to race a 700rwhp motor on 91 octane... That's a lot of power to make on pump gas period. I think that 700rwhp on the edge of safe for pump gas, even if you are low compression.
I did 746rwhp with a 9:1 348ci and 110 leaded, but now that I am 8:1 I might be able to squeak out 700rwhp on pump 93 but I would never race it at the track like that.
I did 746rwhp with a 9:1 348ci and 110 leaded, but now that I am 8:1 I might be able to squeak out 700rwhp on pump 93 but I would never race it at the track like that.
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Verdad Gallardo ya, reason i ask guys is because this car will be a car that i can drive whenever i want, and i dont want to have to fill up will race fuel every time i drive it, just "in case" i see a car i wanna race.
i dont mind putting race fuel in when i go to the track, because it wont happen way too often, but as a daily driver, i cant afford 110 every week.
i dont mind putting race fuel in when i go to the track, because it wont happen way too often, but as a daily driver, i cant afford 110 every week.
TECH Fanatic
Joined: Oct 2003
Posts: 1,839
Likes: 0
Boost is a measure of restriction not power.
So you can safely run 40 psi on a stock motor
Also, if you're serious about a big power daily driver, look into methanol (or some other fuel in a reserve tank). You still drive around on 91/93, and the meth (or alky or race gas) kicks in when you are boosting high.
So you can safely run 40 psi on a stock motor
Also, if you're serious about a big power daily driver, look into methanol (or some other fuel in a reserve tank). You still drive around on 91/93, and the meth (or alky or race gas) kicks in when you are boosting high.
ATI Procharger's car has 1800hp on pump gas!!! how do you explain that? it's a BBC with 427" and non-exotic parts mainly. 8.18 @ like 170 or something. anybody? just curious, as i am purchasing a motor built nearly identical in rotating assembly, but the same heads, custom turbo cam, and a better intake, and same 427 sbc. that car made 1200 hp and 1000lbft. at the flywheel. you can see that car at monteygwilliams.com. and that was with a small fmic, twin turbos, 92 octane, and a conservative tune. he's a friend of the guy i'm buying the motor from, also a member on the board. (not montey, the guy i'm getting the motor from).
thanks,
Dave
thanks,
Dave
Originally Posted by Pro Stock John
700rwhp on 91 perhaps, but I doubt that I would want to race a 700rwhp motor on 91 octane... That's a lot of power to make on pump gas period. I think that 700rwhp on the edge of safe for pump gas, even if you are low compression.
I did 746rwhp with a 9:1 348ci and 110 leaded, but now that I am 8:1 I might be able to squeak out 700rwhp on pump 93 but I would never race it at the track like that.
I did 746rwhp with a 9:1 348ci and 110 leaded, but now that I am 8:1 I might be able to squeak out 700rwhp on pump 93 but I would never race it at the track like that.
Now John,
You know better than that. Remember I am making 800RWHP, VERY SAFELY, and I dont run anything but BP 93 and I do it on 10lbs of boost. 9.8 to 1 compression.
Shame on you!
I am redoing this post of mine.
Bryan, you posted going 12.5@116mph or something at Darlington a while back, was that with your motor detuned to 425rwhp?
Making 800rwhp on the dyno, with the motor zinging thru a pull for 3-4 seconds is sure different then making a 10-11 second pass. Which generates more heat, a dyno pull or a track pass?
Bryan, you posted going 12.5@116mph or something at Darlington a while back, was that with your motor detuned to 425rwhp?
Making 800rwhp on the dyno, with the motor zinging thru a pull for 3-4 seconds is sure different then making a 10-11 second pass. Which generates more heat, a dyno pull or a track pass?
