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To give some perspective, crawled under the car after work to snap a pic. Forgive the mufflers being out of plane.. this setup has always been "temporary". The mufflers (Flowmaster 50 series, long case.. grossly restrictive) are 4" thick case, 2.5" in/out.. so the Dynomax mufflers I'm looking at are 4.5" thick 9.75"x14" case with 3.5" in/out, and Magnaflow's version is a 5" thick case with 8"x14" case. You can see how high up the rear axle is stuffed relative to the mufflers (as high up as they can go). The ride height is right at 2.5" compressed on 5" total stroke shocks.
When I renew my setup I will go to a minimum of 3.5" and will work my sheetmetal to get the over axle fit. I will also use the oval, and may as well tell you now, I'll work in electric cutouts tied into secondary fuel map.
Also.. 3.5" is 36% bigger than 3", and 4" is 78% bigger than 3"... how much exhaust flow are you planning on needing in the future? I can't imagine 4" exhaust would drop that much more backpressure vs 3" in comparison to 3.5" vs 3"? Also would the drop in exhaust backpressure when running cutouts (on the downpipes I presume) really need a different fuel map?
I read a little in that thread, specifically around the idea that a smaller crossover gives a more responsive/more better performance setup. What it rattled from my memory banks from working at Garrett years ago is that turbines gain efficiency from pulse flow. When you put a turbine on a flow bench (smooth/constant flow) you will get a lower efficiency than when you put it on an engine, especially at low flow/RPM, because the pulsating exhaust boosts the turbines efficiency. This is why split housings are used. If you have a larger crossover pipe, the volume of the pipe is going to dampen the pulses and I think that is why a smaller crossover may be more favorable.
That concept only applies to the inlet side of the turbine.
Very cool to know, thanks for chiming in Clint. From reading that thread, my existing hotside piping (OD=2.5", so ID=2.375") is quite a bit bigger than necessary, so the future twin setup will have somewhere in the neighborhood of 2.0"-2.125" ID and hopefully less than 18" length of thick wall hotside pipe per turbo, maybe even closer to 12".. which should keep the exhaust velocity up as well as consistent, and minimize the distance over which heat could dissipate.
Something I've thought about, which is admittedly academic, is whether or not a crossplane V8 like this would benefit from 180 style headers with the evenly spaced pulses split into a divided ("twin scroll") turbocharger. Lots of plumbing required for something like that and I kind of wonder if the oddly-spaced pulses would be a benefit anyway... I have no idea.
Yeah.. twins are the next stage of the build (see previous page of the thread) but the immediate work will be free flowing dual exhaust with large Y-pipe after downpipe, slightly reworked crossover pipe to allow thicker rad+fans cooling setup, some firewall and floorpan heat shielding, and some big *** vents in the hood.
Also want to redo tank setup with the Holley Hydramat replacing the labyrinth setup I originally made as I fuel cut under boost out of corners when tank is less than maybe 1/3 full. Also need to rebuild tilt steering column and make inner fenders. All the while being on the lookout for discounted BNIB twin Precision 64/65, Precision 66/67, or Turbonetics GTK650 turbos from someone's project gone stale.
My thought is if you are going to be rebuilding the engine, redoing a lot of the exhaust and crossover, and then having to tune the new setup, you are putting a lot of work into this single turbo configuration. It might be time to just jump into the twins. Actually since Mark already has twins, you should go for triplets. Or how about a pair of single sequential turbos like this http://www.powerstrokehub.com/sst.html (I'm a little partial since I helped develop that technology when I was at Garrett).
Good points, Clint.. My thoughts are that the new exhaust system will be compatible with twins from the driveshaft loop crossmember rearward.. so the only exhaust work I'd be doing now for the single but would then undo for the twins setup would be between the end of the downpipe to the start of the oval duals rear of the tailhousing.. maybe about 2ft of tubing.. no biggie.
The modification of the single hotside crossover pipe for rad fan clearance isn't a big deal, and realistically is a mod that would be needed to make this arrangement more accommodating/universal should I end up selling it to someone in the future.
And the tune isn't a big deal.. I'll need to adjust the fuel map for the stroker engine under boost regardless, and changing to twins may add some extra boost up top, but will definitely add boost down below... don't forget I have the Holley software so it'll self-learn
Also want to redo tank setup with the Holley Hydramat replacing the labyrinth setup I originally made as I fuel cut under boost out of corners when tank is less than maybe 1/3 full.
Sad! What's your fuel setup again? I recall you had the 340 in-tank for a bit, but didn't you replace it with twins or something? And what regulator are you running?
I had a single Aeromotive 340 Stealth, which I replaced with dual TRE 300's (hopped up Walbro 255 supposedly) which have worked well for me since installing. I'd like to remove all the mild steel baffling inside the tank and replace with a full-area hydramat.. the demo videos of how well the hydramat works is quite frankly mind-blowing.
Yeah, I saw the Kibbetech Racing trophy truck article, seems good. Not many reviews outside of that, though. I'm also considering a gen5 Camaro in-tank setup, with the integral regulator.
I had a single Aeromotive 340 Stealth, which I replaced with dual TRE 300's (hopped up Walbro 255 supposedly) which have worked well for me since installing. I'd like to remove all the mild steel baffling inside the tank and replace with a full-area hydramat.. the demo videos of how well the hydramat works is quite frankly mind-blowing.
That sucks to hear about still having slosh issues with the baffle you made, I was going to try and do something similar on my setup. I have been going back and forth on the hydramat and trying to mod the tank.
I'm not completely convinced on the hydramat. Let's say you park on a slant and leave the car there over night. If one end of the hydramat goes uncovered, wont the surface tension eventually let go to evaporation and leave an exposed area of the mat to draw air from when you go to start it the next time? Maybe it's great, maybe not, but if it were mine I would not want a full-tank sized mat, but something a little smaller and still with some baffling around it so it's the last thing to get unwetted. The hydramat concept is really no different from the pickup sock that normally goes on a pump - it's just a much larger version.
If it were mine, I would put a lot less focus on the rear tank and instead make a surge tank up front to keep the primary fuel system on the engine fed properly. The aspect ratios of the rear tank are unfavorable for preventing fuel starvation and IMO the hydramat is just a bandaid to that problem.
I have an Aeromotive adjustable FPR, on the firewall, boost referenced 1:1.
Originally Posted by 408GT
That sucks to hear about still having slosh issues with the baffle you made, I was going to try and do something similar on my setup. I have been going back and forth on the hydramat and trying to mod the tank.
Yeah it's a bit strange.. most of the time it would be fine, but sometime it would fuel cut briefly.
Originally Posted by -TheBandit-
I'm not completely convinced on the hydramat. Let's say you park on a slant and leave the car there over night. If one end of the hydramat goes uncovered, wont the surface tension eventually let go to evaporation and leave an exposed area of the mat to draw air from when you go to start it the next time? Maybe it's great, maybe not, but if it were mine I would not want a full-tank sized mat, but something a little smaller and still with some baffling around it so it's the last thing to get unwetted. The hydramat concept is really no different from the pickup sock that normally goes on a pump - it's just a much larger version.
If it were mine, I would put a lot less focus on the rear tank and instead make a surge tank up front to keep the primary fuel system on the engine fed properly. The aspect ratios of the rear tank are unfavorable for preventing fuel starvation and IMO the hydramat is just a bandaid to that problem.
Very good points.. and I totally agree on the sizing of the our tanks.. they're wide and short in height.. worst case for trying to contain liquid from sloshing. I'm not too familiar with pickup socks.. I thought those were mainly used as a pre-filter for rust and big grit particulate.. didn't know they have the surface tension mechanism similar to the hydrmat. I'm not set on the hydramat, and quite frankly the current labyrinth works well almost all the time.
I remember way back at the beginning of the thread I think I uploaded a hand drawn diagram of a fuel system with a transfer tank up front, but then abandoned that setup for simplicity. I'm going to remove the heater from the car, which will free up valuable space on the firewall (right were the FPR currently is), so I may re-investigate a transfer tank setup. But it's also a 2nd pressure pump with associated wiring, more fittings & connections (and thus things that could leak) and a nice big heat sink to absorb all that engine bay turbo heat. Then again it's a spot to let all that disturbed fuel pumped all the way from the gas tank hang out and maybe de-aerate.
Another thought I had was to put a small "sump" into the bottom of the tank (maybe an inch or two deep) and extend a baffle like you made into the tank.
If you watch the youtube video of it: it looks like it can be uncovered and still function without sucking air.
That is true once the mat is initially wetted, however if the mat is dry and you only dip one end of it into fuel I really doubt it will pick anything up at all. The only way that would work is if there is enough wicking for it to soak fuel across the entire mat starting from one end. Perhaps there is, but I don't think I would want to rely on that.
Originally Posted by frojoe
But it's also a 2nd pressure pump with associated wiring, more fittings & connections (and thus things that could leak) and a nice big heat sink to absorb all that engine bay turbo heat.
Actually you only need low pressure transfer pump coming from the main fuel tank. You vent the surge tank so it is at atmospheric. Your main pressure pump(s) lives in the surge tank. You can either have the pressure regulator return dump back to the surge tank or go all the way back to the main tank. Returning to the main tank allows the fuel to cool back there so there is always a supply of cooler fuel coming into the surge tank. Surge tank provides a favorable aspect ratio and a consistent head (amount of fluid above the pump) to maintain an air-free supply of fuel to the engine, even when the transfer pump is delivering air.
Actually you only need low pressure transfer pump coming from the main fuel tank. You vent the surge tank so it is at atmospheric. Your main pressure pump(s) lives in the surge tank. You can either have the pressure regulator return dump back to the surge tank or go all the way back to the main tank. Returning to the main tank allows the fuel to cool back there so there is always a supply of cooler fuel coming into the surge tank. Surge tank provides a favorable aspect ratio and a consistent head (amount of fluid above the pump) to maintain an air-free supply of fuel to the engine, even when the transfer pump is delivering air.
Oh yes, I know that.. sorry I meant that a surge tank setup requires a pump at each opposite end of the car.. hence the pain in the *** with wiring, especially since my fuel pump solenoid is above the rear axle and the battery is in the trunk.
01-09-2017, 08:45 PM
