Sc14 to buick and e85

[TdracerTd]

yeah im interested to see the max boost the sc14 makes and how much it drops off at higher revs, interested as I have a mate with one on a v6 in a Gemini

On the dyno we saw a max of 185 KPA on the MAP. So about 12.5 PSI with a 72mm pulley. As for the rest of the day on the dyno, I don't really want to talk about it.

[Holden202T]

that doesn't sound good

[TdracerTd]

Not too bad, could have been worse. I think i'm on top of it now. Just short of money and time before Gatton Street Sprints, due to burning a whole day of dyno time chasing weird problems that I didn't see until 5000RPM under load.

BTW, I'm also seeing a little belt slip and still achieving 185KPa, so I think there is more in it. It holds that boost all the way to redline, when it makes it to redline.

[Holden202T]

ahh right cool.

if it makes you feel any better I've been to the dyno more than once and had a day of wasted time

[TdracerTd]

Got it running nice and smooth on the dyno on Saturday with the help of a very knowledgeable friend (not sure he wants to be named), although, the day didn't go without problems. A shout out to Dyno Hire Services. They provided the dyno at a very reasonable price and were very accommodating and helpful.

We didn't make much more power but lowdown torque is up and the car is a pleasure to drive with power on tap.

Graph-

image1.JPG (363.06 KiB) Viewed 3514 times

You can see the boost creeping up in the top end, I think this is down to the engine not being able to breath it at those revs. I think some head work and a cam should help with this, but at current power levels the SC14 seems to be able to keep up with demand.

Here is the log from the that run too if anyone is interested-

Final_Log_Dyno.xdl

(38.37 KiB) Downloaded 219 times

At this point I have spent more on dyno time then I have Improving the engines performance, so I'm pretty happy.

Any input appreciated.

[Holden202T]

its interesting that its making so little boost down low then increases in the top end, I certainly would have expected to see more down low with the smaller pulley you have!

either way a good result!

I can certainly relate to the countless dollars on the dyno with often not much result, but you get to nut out all the issues so that's a clear bonus!

just out of interest I assume you are tuning it on E85 but using petrol AFR ratios ? .... that's all I can make out from the log ?

looks like 46 degrees inlet temps is all happy

[TdracerTd]

its interesting that its making so little boost down low then increases in the top end, I certainly would have expected to see more down low with the smaller pulley you have!

Talking to the L67 gurus, with a PD blower, boost is a measure of restriction, ie. the more boost, the more restriction. I guess looking at that graph, and the fact that it's on a stock cam and heads, it would make sense that it breathes better down low in the rev range. A more suitable cam and some head work, in that case should help. That's providing there's not some other problem that I don't know about yet. Theoretically, you shouldn't run out of boost at higher rpm's with a PD blower, more of problem would be the parasitic drag, especially with the SC14 as the lobes on the rotor are straight. Coming from turbo cars, there has been a lot I have had to relearn.

just out of interest I assume you are tuning it on E85 but using petrol AFR ratios ? .... that's all I can make out from the log ?

Yep, that's right. All the dynos I have used are either in Lambda or Petrol AFR's and I got sick of having to do the conversion also, being a beginner, when I was talking to people it just caused confusion, so I converted all my tables to Petrol.

looks like 46 degrees inlet temps is all happy

Very, very happy with inlet temps. I think there could be some improvement here too, as my return pipe runs straight past the radiator and directly under the headers on the passenger side. You can feel the conductive heat in the pipe. Custom intake manifold is next, so it will shorten the path from the cooler and direct the piping away from the heat.

[Holden202T]

yeah im certainly no expert with blowers, but have done boost turbo stuff, so it is certainly different, mines more like takes time to build boost, then flat lines full boost till redline .....

I guess im more surprised the SC14 doesn't make more down lower then peak and then drop off as rpm rises ... would be very interested to see the torque curve, that's the big thing!

yeah I understand about dynos in lambda, my dyno uses that and when I goto the dyno I put my innovate wideband display in lambda for him hehe, still have methanol AFR's in the logs so I can compare to my targets and I never normally tune off the innovate gauge just the wideband input or the dynos wideband.

I also noticed it looks like your about bang on with injector size, 86% duty cycle at the end of the power run!, what size are they ?

[TdracerTd]

Yeah, I didn't get a printout of the torque curve. But it is much the same as the boost only opposite. :LOL It Starts higher goes flat for a long way then drops off in much the same manner as the boost curve builds. lend more to the the theory that the boost is only showing you how much restriction there is. remember a PD blower's air output is linear, one rev produces x air and the engine consumes y air per rev. A turbos boost is controlled by the waste gate/boost control circuit so, once spinning fast enough will feed as much air as is required to maintain the boost set by your boost control circuit. Anyway that's how I understand it.

The injectors are 60lb seimens. I'm not sure of the math, but they may have more in them as we set the KInj flow to a very conservative number to ensure we had resolution in the VE tables.

[Holden202T]

yeah to measure a turbo in the same manner as your measuring the blower you'd really need to measure how much air flow is coming through the gate as that would be the varying factor!

as for you injectors, it wont change things if you change the injector rate as if you change it one way or the other you just have to offset the ve table the same to suit, really as long as your VE table is not going over 100 then theres nothing in the VE or injector rate that is going to need to be changed.....

injector duty cycle is a calculation of how much of the cycle the injector is open for, it will be able to go slightly higher than what you have now with an adjustable regulator and more pressure at idle (note this will throw all the ve settings out too probably ) ....

either way I reckon you'll have enough in them with the head and cam changes to not need to upgrade anything other than pressure regulator if you haven't already.

I am running deka 80's with about 10psi more than stock pressure off boost, then increases 1psi for every psi of boost and I see about a max of 65 psi at 21psi boost ... I've heard you can go a bit higher than this pressure wise with deka's but I have no need to so haven't tried!