Project STi Time Attack

frayz · Post by **frayz** » Wed Jul 04, 2007 6:42 pm

My my grandma... what a massive banjo you have

Gerry H · Post by **Gerry H** » Wed Jul 04, 2007 6:46 pm

What injectors are you using? If they are Sard twin hole, watch the O ring size. They send out the wrong sized rings for the phase 1 injectors and you end up with a sump full of petrol

duncan · Post by **duncan** » Wed Jul 04, 2007 7:48 pm

They are modified std injectors from Lateral Performance - I believe they flow around 800 cc. Will take some pics before they go in on Friday

Gerry H · Post by **Gerry H** » Wed Jul 04, 2007 8:19 pm

No problem then :-D but thought I'd mention it just in case, 800 being an odd size.

duncan · Post by **duncan** » Wed Jul 04, 2007 8:22 pm

then again they may be 740 - will see what they flow at when the mapping is done :thumb:

either way they will be more than adequate for my humble targets 8)

frayz · Post by **frayz** » Wed Jul 04, 2007 11:54 pm

Theyre 740cc Dunc. Same as mine

sdminus · Post by **sdminus** » Thu Jul 05, 2007 6:44 am

I dont know if it suffers the same buy denso 850cc injecotors (used in the fd3s) casue problems when they are enlarged. I have heard of many problems and lost engines. When this is done to injectors it destroys the spray pattern and therefore gives poor atomisation.

Scott

duncan · Post by **duncan** » Thu Jul 05, 2007 7:25 am

Thanks for the concern Scott, the injectors are professionally modified and balanced for flow rates and checked for proper atomisation of the fuel. The reason for using modified rather than larger is to keep the injector opening lag the same which can cause very uneven idle when changing to bigger injectors on EJ engines.

This way, we can purely scale the flow rates to reduce the IDC and put the boost back up to a proper level to use the newly available fuel as we know it flows the air now.

Prior to the APS kit it was flowing a max 290 grams/sec air at 1.45 bar, now it is flowing 300 at 1.2 bar and has the capacity to flow 465 grams/sec if the rest of the engine could either take it or provide it and still be within appropriate map cells to ensure correct fuelling. I am expecting it to come out with around 330 grams/sec but will report back once mapping has been done with results of logging.

We will maintain AFR at around 11:1

Some maths for Scott

330 grams/sec equates to 19.8KG/min of Air coming into the engine.

At 11:1 this would equate to 1.81kg/min of fuel

Shell V-Power has a density of 754kg/m^3, or 0.754g/cc.... we have 740cc worth of fuel per injector and there are 4 injectors, so we can move 2960cc/min of fuel, which at 0.754g/cc is 2.232kg.

Assuming 330 grams/sec air coming through the injectors will run at approx 81% IDC

With normal fuel you end up with somewhere between 20 and 22 BHP for every kg/min of air that you move through the engine.

If we run at an AFR of 11:1 this would yield somewhere between 396BHP and 435.6BHP

frayz · Post by **frayz** » Thu Jul 05, 2007 8:14 am

dynamix wrote:
Some maths for Scott

330 grams/sec equates to 19.8KG/min of Air coming into the engine.

At 11:1 this would equate to 1.81kg/min of fuel

Shell V-Power has a density of 754kg/m^3, or 0.754g/cc.... we have 740cc worth of fuel per injector and there are 4 injectors, so we can move 2960cc/min of fuel, which at 0.754g/cc is 2.232kg.

Assuming 330 grams/sec air coming through the injectors will run at approx 81% IDC

With normal fuel you end up with somewhere between 20 and 22 BHP for every kg/min of air that you move through the engine.

If we run at an AFR of 11:1 this would yield somewhere between 396BHP and 435.6BHP

Dunc... there are sessions you can attend to talk about problems like this. You all sit in a nice big circle and talk about your problems

duncan · Post by **duncan** » Thu Jul 05, 2007 8:15 am

:lol: