If this is your first visit, be sure to
check out the FAQ by clicking the
link above. You may have to register
before you can post: click the register link above to proceed. To start viewing messages,
select the forum that you want to visit from the selection below.
I like the transfer pump and reservoir idea. Low pressure to the reservoir and then high pressure from there?
Yup. You could implement the same idea completely in tank to keep things tidy by just adding a couple hose connections at the filler plate and an external supply pump to the container. Just have an extra switch so you can flip over to the reservoir once the pressure starts to drop. That should give you a couple laps warning without having the lap times drop.
As for the rest, a very wise and experienced racer/racecar fabricator told me to manage airflow...all of the radiators, intercoolers, oil coolers, etc., won't make any difference if you can't get air to flow through them and out of the engine compartment. He makes sure everything is in direct airflow and the surrounding areas of the coolers sealed so that air cannot go around the coolers. You'll only know this with sustained runs at racing speeds, however.
He's also big into making sure your oil supply is never interrupted (Accusump good!) but also make sure that the oil is always around the oil pump pick-up using proper baffling. Might as well put in a windage tray/main studs etc., too.
Another point is to make sure the water pump does not cavitate at the rpm's you'll be racing at, so ask around for what pumps and pullies to use.
Also, practice brake pad changes per axle to line up with gas stops. My pad changes were fronts every second stop (4+ hrs) and rears every third stop (every 6+ hrs). Brake pad changes were always done before refueling was completed. One guy did both sides, a side at a time just to eliminate the possibility of mistakenly blowing out a caliper piston.
wow, thats a fast brake change. is that with stock calipers? I guess with proper maintance on parts, and doing it a few dozen times, and power tools you can get into a groove, but still...
They started off as stock calipers and were mildly massaged. I made up thicker pads on the mill from DS11 pads for an AP Lockheed caliper. Stock front pads would have last less than an hour. Front calipers saw some time in the mill. Rear calipers had lathe time removing the threads from the park brake mechanism so that the piston could be retracted with channel locks. Remove one slider bolt, hinge the caliper out, kick out the old pads, slide in the new pads, retract the piston, replace the caliper and bolt. Wham bam, done deal. The only air tool used was for removing the wheel.
Thanks Mike. By the way, love those Catholic girls.
So using .7 full throttle, 154 hp max on 22 gallon tank for a two hour interval.
250 hp would be 14.7 gallons per hour. So we could run 1 and 1/2 hours on a 22 gallon tank. So we need ~ 8 gallons more to get two hours.
Of course that means at the wheel we are looking at .85 of that number so... 212 at the wheel.
Pretty tame engine.
Ok, so we are looking at a very tame build, can we increase fuel efficiency with a higher CR and low boost? Let's say 10:1, less than 10 psi boost?
Technically we shouldn't be using boost pressure as a determinate, we really need to talk about airflow. I think we'd need to pick a turbo with as low a backpressure as possible in the 4000 to 6800 rpm range. Who cares about something that comes in earlier than that, we don't drive down there.
Ok, so we are looking at a very tame build, can we increase fuel efficiency with a higher CR and low boost? Let's say 10:1, less than 10 psi boost?
higher CR => lower boost requirement => less heat in charge air (normally..) => more timing => lower BSFC = good stuffs.
Technically we shouldn't be using boost pressure as a determinate, we really need to talk about airflow. I think we'd need to pick a turbo with as low a backpressure as possible in the 4000 to 6800 rpm range. Who cares about something that comes in earlier than that, we don't drive down there.
running the turbo in crossover is pretty much a requirement when dealing with BSFC related performance. a t3 cold side could supply the needed 25lb/air at .7PR at ~68% eff. more modern turbo would put less heat into the charge air. (ie: T04E 60 trim sits around 80% eff at those PR and flow) a VATN would be wonderful for backpressure.
Alex, great input thanks. Crossover would be awesome. 80% efficency would be incredible. My next task was going to be to start combing the compressor maps. You've helped narrow it down.
Haha. I like that Corky Bell quote in their website. "The VATN is a whole new deal." . That tells you how old his book is.
The VAT or VNT was designed and patented at the now defunct Turbotech in North Hollywood between the years of 1978 and 1982. The prototype was installed on a daily driven Lancia Scorpion. Concurrent design and development was being done by John Knepp and Don Devendorf at Electramotive, and several patent right phone calls were made to remind them about the patent. The patent rights were eventually bought by Garrett.
To answer your question, several manufacturers have used VAT or VNT.
Ok, so we are looking at a very tame build, can we increase fuel efficiency with a higher CR and low boost? Let's say 10:1, less than 10 psi boost?
Technically we shouldn't be using boost pressure as a determinate, we really need to talk about airflow. I think we'd need to pick a turbo with as low a backpressure as possible in the 4000 to 6800 rpm range. Who cares about something that comes in earlier than that, we don't drive down there.
I think that you have reached just about the optium that the 2.3 likes in the way of compression and be safe. What you should be looking for, optiumizing squish and maximizing swirl. Bo can give you some good ideas on that. Do Pats mods, pick up a nice ball bearing turbo, put in the best intercooler you can get, run some higher RPMs and go have some fun! If you are looking at turbos and airflow consider the cam choice too.
. Do Pats mods, pick up a nice ball bearing turbo, put in the best intercooler you can get, run some higher RPMs and go have some fun! If you are looking at turbos and airflow consider the cam choice too.
in the vein of best intercooler, have you taken a look at going water/air. Since the conductivity between air/water vs air/air allows for much higher charge heat extraction per area in the IC, you can run a much smaller sized IC for the same amount of heat removal, and the resultant lower pressure low and increased flow. The downfall is it weighs more and you have another pump to fail.
less flow restriction = lower compressor outlet pressure = lower compressor outlet temperatures and lower turbine inlet pressures = MORE POWER.
since you also have a higher thermal mass in the system, you can toss a slug of hot charge air at it for a short period (overboost, push to pass, etc) and not have skyrocketing air temps.
edit: just thought of this, you can also mount the radiator for the IC in the shade (under the rear end), which _might_ mitigate some of the stupidly hot air temps on track.
We process personal data about users of our site, through the use of cookies and other technologies, to deliver our services, personalize advertising, and to analyze site activity. We may share certain information about our users with our advertising and analytics partners. For additional details, refer to our Privacy Policy.
By clicking "I AGREE" below, you agree to our Privacy Policy and our personal data processing and cookie practices as described therein. You also acknowledge that this forum may be hosted outside your country and you consent to the collection, storage, and processing of your data in the country where this forum is hosted.
Tweet
Comment