Success!

After an eternity (actually close to 3 years) of engineering/building/ configuring/re-engineering/installing/removing/re-installing, I fired my 383 this morning! The last hurdle was the LTCC wiring, but I got that sorted out (at 7:30 AM after 3+ hours of sleep ). It idles relatively smoothly with 16" of vacuum, and the coolant temp never went over about 185. Of course, I will need to actually finish putting it together and take it off the jackstands for a real test .

Many thanks to all here that have assisted with the many issues such as oiling (getting about 50 psi @ idle on the gauge), fuel injector sizing, and all the other stuff I've asked for help with and have received just what I needed.

I'll be updating the webpage within a few days- there are still a few more things to be worked out but at least I know it runs well.

 

http://memimage.cardomain.com/member...7_112_full.jpg

How did you firgure that??

I estimate i am around 490 rwhp right now
my 42# ing are running a 104% DC
stock FP


You saying if i up my FP i should be able to go 574 hp at only 80%dc?

beautiful car btw

 

Thanks- even more beautiful now that I know it runs . I am a big fan of the 8 coil LTCC setup, my Bonneville uses a similar factory setup & fires by bumping the starter. It was neat to see the 383 do the same thing since my old 80K mile LT1 would spin several times before firing.

I got many calculators & data for my calculations from Superchargers Online. When I visited that site tonight, I see they only have one calculator there, but they allow a free download of more intensive calculators. I can't remember all the sources right now, this form was done in a program called Omniform and it lets you make calculations based on data among other things.

Here is the math & sources for my numbers:
To convert the injector size at higher pressures, I used 1.072 for 50 psi, 1.124 for 55 psi, and 1.174 for 60 psi.

The Walbro pump data came from a webpage that did not have the GSS340 data, so I did a calculation based on the difference between it & the standard pump (307) and came up with a 12% performance improvement.

I found another webpage that lists the Walbro pumps with more data, as well as flow at 13.5 volts:
http://www.autoperformanceengineerin...l/fpspecs.html

Based on that data, I was right on with the 12v numbers, and too conservative with the 13.5 numbers, which came in at:
PSI My Flow Their Flow
40 66 70
50 60 65
60 56 61
70 50 56
80 41 51

I always try & figure numbers on the conservative side, as any variance is usually in my favor, which is certainly the case here.

The formula used to convert GPH to LPH is GPH x 3.785.

For the base HP to blown HP, the numbers used are on the form & come from Superchargersonline (I think there was some variance here as the lower boost used a 2 core IC & the higher boost used a 3 core).

The combo chart took the final injector size from the box in the upper left, I typed in the duty cycle (.80 in this case), # of cylinders (8), the pump output was calculated as injector size x duty cycle x # of cylinders x .63, which I believe is a formula found on an injector website. The Brake Specific Fuel Consumption was set on this chart at .55- I've seen blower motor figurs lower & higher, so I settled here. The HP is calculated by injector size x duty cycle divided by BSFC x # cylinders.

In my 383, I know I have 55#/hr injectors. If I run these at an 80% DC with a BSFC of .55 on an 8 cylinder motor, I should net out about 640 HP, which was close to my 8psi blown figure of 628 HP. The base 400 HP figure was due to Chevy High Performance's figures of 429 HP on a LT1 with LT4 heads, intake, Hot cam, and 52mm TB. Since I was running 9:1 CR vs. 10.5:1, I knew I would have less power, but I also have increased displacement, so I rounded this figure down to 400 HP.

I hope this answers your question.

Here is the link to the Superchargers online calculator:
http://www.superchargersonline.com\h...r.asp?submit=1

/Edit

I visited your webpage, great setup! I think your motor internals are exactly the same as mine with the exception of the stroke. I'm looking forward to
Using my math, if you can pressurize your injectors to 60 psi (I recently read some posts here about the viability of an AFPR due to the PCM setup), you will have in effect a 49# injector, which should support 574 HP vs 489. I had a set of the 42# units before I bought the Procharger and ended up selling them and putting in the high impedance 55# units. Based on your numbers and setup, I would go with larger injectors vs higher FP.

Racetronix, a supporting vendor, had the best deal on the Siemens 55# high impedance injectors- $500/set of 8. Unfortunately, he was sold out when I needed mine & I had to go elsewhere.