I would like to know how many people on this board are running 550 to 600rwhp with an intercooled blower on 91 octane gas and how long they have been running this combo.

I've been slowly collecting parts for my 383 rebuild over the past 6 months. I realized that I never even thought to ask if my goals are achievable (since most people run 93+ octane). The car is a daily driver (40miles/day) and has to run on our ****ty 91 octane gas (all I can get). If I can't reach my goal, I may as well quit while I'm ahead, rebuild it cheaply for around 450rwhp and put all the extra $$ somewhere else. The plan was a forged 383, AFR heads, 8.5:1 CR, XE cam, twin intercooled D1SC, 72# injectors with impedance converter box, dual in-tank pumps, water injection, street twin, beefed up tranny/driveshaft/12bolt rear.

The car has to be reliable because I want to enjoy all the time/money I'm putting into it. Failures of the tranny/rear would be OK, but I don't want to spend big $$ on an engine and have to pull it every year (not fun in an fbod). If this combo will not get me to 600rwhp, or will be breaking all the time, it just won't be worth it. I want to spend more time driving my car than my beater. I've seen too many people collect all this stuff, drive the car for 2 months, decide they can't stand all the breakdowns and sell off everything.

I'd really like opinions if the above will get me there (from personal experience) or if I am wasting my time dreaming.

Thanks,
Brent M.

 

Keep in mind, that all dyno's are different. Not only that- but a real 600rwhp should net at least a 140 mph trap speed in a 3500 lb car.

My buddy Vince runs 160+ in the 1/4 and makes "only" 720 rwhp. Makes ya wonder about some of the "1000 hp" guys out there that can't bust 130.

Of course, who am I to talk. I'll be lucky to bust 120 this year on the temp setup. lol

Steve

 

It might be costly and a pain in the @$$ but couldn't you just dump a bottle of Octane boost in ever time you fill up? Not like it would need a whole bottle all the time. Where are you from Cali? Why the $#!% gas? That sucks that you can't get anything better than 91. Personally if I was the EPA, we wouldn't have anything below 93 to run on.

Ahhhhhhhhhhhh, have to love traction don't ya? No wonder them Supra Guys love to race on the rollers because they don't actually have to truely put the power to the ground.

 

I hope you're kidding about the bottle of octane boost.

You realize that when they say that it raises the level of octane 1 point that they mean .1?

It would be easier and more cost effective to mix with racegas or do your own tolulene mix than spend $3 a bottle on 10 bottles of octane boost that doesn't do anything.

 

That's because people concentrate on peak numbers, and not the area under the curve.

 

You'd be suprised how much power a non lockup converter can cost on the dyno, especially in something with a lot of power. You can also spin the heck out of the tires and not even notice it.

As for the 1000rwhp cars, take a look at the power curve. If they make 400rwhp at 5k rpm and 1,000rwhp at 5500rpm then they probably aren't going to be very fast. Most of the big power cars (thinking Supras) have a monster turbo that takes forever to get spooled up and they have to keep shifting gears, getting out of the power band.

Here is a 965rwhp graph btw, I just think it looks cool

 

ROFL.....that looks cool but the thing that's so funny that it is so characteristic of HUGE turbo cars ie. single turbo Supra.

 

I wonder just how much you loose on a non-lockup.. most cars at WOT are not locked up anyhow..

I've been wondering about that, because I thought my HP was a bit low.. but then I considered the stock heads and intake, and just accepted it. I also know you loose some hp for the big, soft Hoosier tires, even though I aired them up to 18 psi, which is pretty hard for them!

Is there a given number for say, a 3500 non-lockup and some 31x 16.5 soft tires??

 

bwahahahhahahahahahahahahahahaahha

octane booster ROFLMAO im not even gonna comment cause im laugin too hard right now

 

No simple answer to this one. But my simplified answer is that a reliable 600rwhp with a blower car on 91octane is barely possible. Some of the issues have been touched on, which is that dyno numbers can be misleading. The conditions must be specified. Amd the transmission will strongly influence dyno numbers. The difference between an automatic with a loose converter and a manual can be in the 10% range. And as far as reliability, a lot will depend on how it's driven. If you drove conservatively except under optimal conditions, that would make a big difference as would the tune.

So, if the car were an M6, and the dyno run showing "600rwhp" was done under optimal conditions, and the driver were very careful as far as tune and driving habits, yep, it could probably be done. My previous setup ran 10,000 miles over 2 years with no reliability issues and dynoed more than 600rwhp. However, I never ran less than 94octane and would run 100octane unleaded when I was pushing the car or at the track. There was no evidence of detonation damage at teardown, but the bearing were looking pretty shot.

Overall, I'd set my goals a little lower for a car designed to run on 91 octane. That, or look for a perfect day to dyno!

Rich Krause

 

Good point TA! Vince has a VERY flat power curve from 5000 to 8000.

Steve

 

Back on topic, you can't make 600rwhp reliably with a street car and definitely not on 91 octane fuel. Now 450rwhp or maybe even 500rwhp with the right intercooler and you'd be in business. That is A LOT of power and parts will break.

 

If you were wanting this kind of power on 91, I would seriously look into Propane Injection, It will help increase the octane of the fuel as well as cool the intake charge some, should be the ticket for what your looking to do.

Bill

 

Xylene ... 2 gallons per tank will noticeably increase the octane value of your 91 pump gas. I buy it in 5 gallon pails for around C$1.86/liter, that works out to about US$5.07 a gallon.

If you're feeling "frisky", dump in a little extra ... I've been running 15 - 20% Xylene for a year and a half, no ill effects what so ever.

Hope this helps

LWM

 

It really sounds to me like this more of a project than I want to take on. It would be pushing the limits of what is achievable with a street driven LT1 on a reasonable budget. Pushing limits is never good for the pocket book! If I drop my goals to 450rwhp to 500rwhp, I can save tons of money as the rotating assembly does not have to be as good, the heads don't have to be as good and a lot of my existing parts like high impedance injectors and fuel system can stay.

My XE cam (224/236,115LSA,111ICL) with an Eagle 383 rotating assembly, SRP dished pistons, 8.5:1 CR with decent heads on 10# should probably make for a pretty nice daily driver. I'd still go with water injection to try and make up for the crappy gas. Depending on heads, this combo should make the 450rwhp to 500rwhp I would think.

Heck, the money saved will almost buy me a bike that will run 9's or 10's

When I was running my blower at 8psi on my stock block, I always ran a 20% Toluene mix to make up for the 91 octane. Toluene was $50Cdn for a 5 gallon container. I'd dump 1.5 to 2gal per tank which added $20Cdn to a $45Cdn tank of premium (91) gas. Considering I go through a tank of gas every 4-5 days, it got expensive. Heck, just the cost of the Toluene would have paid for nitrous, not even counting the $$ in the blower.

Thanks for all the comments,
Brent M.