4A-GZE supercharged - more power options for Lemons!

[chi-town]

I understand they both have the same max pressure but the volume of air at the max psi is greater with the 14 than the 12.

[yoshimitsuspeed]

I understand they both have the same max pressure but the volume of air at the max psi is greater with the 14 than the 12.

This is something that people seem to think about both superchargers and turbos.

If I replace my turbo with one rated for double the volumetric airflow then my new turbo will flow twice the volume of air at the same PSI and therefore it will make waaaaaaaaay more power. Therefore I will put a GT5541r on my civic at 6 PSI and it will be awesome.

The volume of air moved by the compressor is determined by the motor.
If a motor moves 3200 LPM NA and you put a supercharger on there it will move roughly 3200 LPM boosted. That is measuring volumetric airflow after the compressor. On a supercharged motor that will go up slightly because of the pressure differential allowing more flow during overlap but it won't change a lot.
This is measuring volumetric airflow after the compressor. Of course the volumetric airflow before the compressor will be much higher but after the compressor that increased volume is turned into increased density.

If you have an SC12 on a 4AGE that moves 5000 LPM through the motor at 4000 RPM at 12 PSI and then you replace that SC12 with an SC14 and run 12 PSI at the same intake temp the bigger supercharger will move 5000 LPM at 4000 RPM.
It will move the same volume of air and more importantly the same mass of air into the motor. The motor dictates flow not the compressor.
Now if you put a turbo on that took your efficiency way up and let's say you took your intake temps from 200F to 150F the air would be much more dense. As measured after the compressor the volumetric airflow would be the same as the superchargers but the mass airflow would be higher, the volumetric airflow as measured entering the compressor would be much higher and the power output would be much higher.

[slow_poke]

Ok, so alot has happened, er, well, a lot of time has passed. surprising how little you get done when you're buying a new house... and then a teammate buys house and we're moving the base of operations... anyway.

had a spare block, brought to shop (BEST MACHINE in San Rafael) who did our head / block last time. give Lemon's folks a price break, runs and MR2. all good stuff. Spare block was crap, he got us a new one. so, 0.004 off the head he already machined for 0.008" total, and going for 0.011-0.015" off the block. ideally parts back next week and then put it all back together again...

My calcs put us at around 8.6:1 compression, could probably go higher but we're trying to go for some power and some reliability.

we also have a C50 tranny w/ a 5:1 final ratio and LSD so we'll see if we can get that in. that'll be ~50-60lbs less than the E51. that's worth some time. my calcs say the ratios won't make that much of a difference, but we'll see... i'll see if i can get some plots up. what site do you all use for pics???

[slow_poke]

One more question:

w/ the block and head work i calculate 0.6DEG of change in cam timing... is it worth adjustable cam gears (or at least a set that get's us back to 0.0deg)?

we have ~4 sets of gears and could mount them in a mill and drill new holes if it would help. i suppose we could also fab some adjustables. just don't know if its worth it...

thanks,

[oldeskewltoy]

One more question:

w/ the block and head work i calculate 0.6DEG of change in cam timing... is it worth adjustable cam gears (or at least a set that get's us back to 0.0deg)?

we have ~4 sets of gears and could mount them in a mill and drill new holes if it would help. i suppose we could also fab some adjustables. just don't know if its worth it...

thanks,

Not doubting your figure, just wondering how you calculated it???

**IF** you cam timing is off less than 1 degree, you should be fine without adjustable pulleys

[slow_poke]

my assumption was as the cam gear gets closer to the crank gear the excess belt will wrap around the cam gear, changing the timing. at present its looking like 0.011, 0.012, 0.02" (=0.043" or 1.08mm) off block, head, gasket, respectively. Which, wrapped around the pulley dia of 107.6mm (676mm circumference, or 1.88mm/deg) turns into about 1.08/1.88 = 0.58deg. so, not EXACT but close...

that said, i just noticed my assumption was cam belt & crank belt tangency points are vertically above each other... and they're not.... so i suppose now i'm going to have to go back and redo based on the angles but my guess is that's just going to be a small difference.

i'm also calcing that to be ~8.65:1 compression ratio. (start w/ 36cc headV, 397cc swept volume, & 8:1CR gives me a 20.7cc unswept volume in cylinder and gasket). determine the volume removed due to machining. add back in the volume gained from sinking valves into head from valve job. recalc the compression ratio. my assumption here is the head walls near the face of the head are vertical, if not the compression ratio will be less.

so far, all math. we'll see how it all turns out. see any issues?

[oldeskewltoy]

my assumption was as the cam gear gets closer to the crank gear the excess belt will wrap around the cam gear, changing the timing. at present its looking like 0.011, 0.012, 0.02" (=0.043" or 1.08mm) off block, head, gasket, respectively. Which, wrapped around the pulley dia of 107.6mm (676mm circumference, or 1.88mm/deg) turns into about 1.08/1.88 = 0.58deg. so, not EXACT but close...

see any issues?

It has nothing to do with circumference.... The head(cams) is/are now 1.08mm closer to the crank, so it is linear - as the belt is the measure.

Do you have adjustable timing pulleys? If you have one, rotate the outer pulley just over 1mm, and I believe you'll see something closer to 2 degrees. 2 degrees isn't a huge deal, although I tend to be picky, so I'd check cam timing myself

[slow_poke]

whoa, i hope i'm not confused... sadly no adjustable pulleys. we have a couple sets and we could drill one out to an offset, but that offset would have to be calculated.

two ways i calced the angle (approximately):
a) if i took a string and wrapped it around the pulley it would be 338mm long and it would represent 360degrees, ~.94mm/deg. so my 1.08mm would be 1.15deg (this is what i did which is why i talked about circumference. and look you caught an error of mine! circumference=dia*pi)

b) (this is what i imagined for your way...) drop the center of the pulley 1.08mm creating a right triangle that is 1.08mm vertical and 107.6/2 horizontal. what's the resultant angle. atan(1.08/53.8) = 1.15deg. for a while i was getting 2.3deg because i was in radians rather than degrees... (grrrr.).

anyway, that's what my math is telling me. if you've a pulley and you're seeing ~2deg as a result of the 1.08mm move my head is exploding and i can't account for it. AND i could see that >2degrees likely matters and i need to either get adjustable gears or cut some new holes in one of our sets.

any more insight would be great. thanks

[yoshimitsuspeed]

Ok, so alot has happened, er, well, a lot of time has passed. surprising how little you get done when you're buying a new house... and then a teammate buys house and we're moving the base of operations... anyway.

had a spare block, brought to shop (BEST MACHINE in San Rafael) who did our head / block last time. give Lemon's folks a price break, runs and MR2. all good stuff. Spare block was crap, he got us a new one. so, 0.004 off the head he already machined for 0.008" total, and going for 0.011-0.015" off the block. ideally parts back next week and then put it all back together again...

My calcs put us at around 8.6:1 compression, could probably go higher but we're trying to go for some power and some reliability.

This is one of the great motor misconceptions. Compression does not have a direct effect on reliability. Run 11:1 on your setup and if you can keep it from detonating it will last just as long. The key is keeping it from detonating.
Since you are racing you will put a lot more heat into the SC and into the charge and intercooler. This means that you will likely need to run lower compression than your average joe who might do the occasional 10-20 second pull on the street, dyno or drag strip. Their SC won't have time to head soak. Your SC and outlet temps will get higher since you are continually pumping that heat into the system. If you had enough intercooling to compensate then that wouldn't make any difference but it's likely that would be very challenging to do.
With that said, your most ideal setup will be the one that runs the most compression possible while still giving you an acceptable margin for detonation.
It would be easier to estimate what that safe number might be if you collected post IC intake temps. For example if during racing your intake temps are hitting 350F you would want to run considerably less compression than if they didn't exceed 140F. Or the even better route would be to first try to get your intake temps as low as possible then try to build up your compression.
It's been a while since I read through this thread and I am sure we have talked about this but the key to keeping your setup as ideal as possible will be in making the most power possible at the lowest boost possible. Compression can go a long ways for this but it will be a balancing act.

[slow_poke]

my goal is pre and post IC air temp sensors and we've got a "scheme" where we take two SC14 IC's and run them in parallel in good flow that should go a long way to cooler temps. know that keep the inlet temps (all the way to the cylinder) cooler is MUCH better. and that minimizing the restriction upstream of the SC is also very important... we/re working on it...

thanks for the input!

[slow_poke]

Post race update:

engine built up, installed, broken in. break-in consisted of ~60min of 2500-4500rpm WOT accelerations in 2nd and 3rd gear in a parking lot at work. the car is not that fast and we have some big parking lots. everything looking good

a couple days before the race, re-installed the accusump and primed it. also installed big oil cooler in rear light opening. brought everything up to temperature, drained and refilled the oil / replaced filter during this install.

day of the race everythings working great. the Eibach springs are stiff enough in the front we no longer drag our splitter on hard braking and the car still feels neutral. lots more pop as well, pulling some faster cars on the straights. still scrubbing outside front tire so we need to get more sway bar / more camber / etc. etc. but otherwise things looking good.

trying to keep the rpms generally under 6500 but excursions to 7k...

6hrs 50min into a 7hr race day i was driving and heard a car go by that had a horrible knocking sound... next corner same sound, no other cars around, its me... pulled off, called it in. idled back to the pits and shut it down. debug points to rod knock on #1. Good news is we didn't destroy the block or the head or anything like that. bad news is we're going to need another rebuild.

so, between the accusump and the oil cooler we had ~6.5Q of good synthetic oil but when we shut the car off we didn't have excess in the oil pan. (have a solenoid valve on the accusump). never saw a drop in oil pressure, and oil temp and water temp were rock solid all day. we have good cooling, we were at 185F for the radiator most of the day

questions to the forum:
a) i thought that we should be able to run up to redline w/o incident. is that true? driver #3 i think took it up to redline on a regular basis. "if its pulling i'm leaving my foot in it" recall we're running '85 or '86 NA cams so they don't die around 6500 like the SC cams.

b) the guy that did our head said that we also should also have "conditioned the rods" we took 4 rod / piston assemblies, along w/ a crank, out of a spare engine. the head guy bought us new bearings for crank and con rods (chinese, one size). we used new ARP bolts in the rods. Head Guy said we should machine 0.001-0.0002 of mating face of con rod cap and then assemble, torque properly and re-machine the resultant big-ends. we did not do that, merely dropped in the bearings and tightened things down per the Toyota manual w/ exception of using the ARP instructions on those bolts. does "re-condition the rods' make sense?

i know, i know, and i kick myself, do the one-size chinese bearings make a difference? should we ahve purchased the appropriate matching toyota bearings?

is there anything we're missing? right now we're pretty disappointed (car fire, holed block, rod knock... 3 failures in 4 races)

right now we're thinking a) we're missing something important, b) these engines are really not up for endurance racing, b) we bought the wrong bearings and if in the future we open up an engine we need to get new connecting rods, new rod bolts, etc. etc...

oh, btw, engine mods: machined head, machined block, MLS gaskets (calc'd 8.9:1 compression ratio), JDM pulley on SC, NA cams. no other mods. pulled great. felt like another MR2 w/ a 2zz couldn't really pull away and we could totally dust a really lightened '85 NA, at least in the straights.... they've got a better sorted suspension

any help here would be great.

[oldeskewltoy]

Post race update:

6hrs 50min into a 7hr race day i was driving and heard a car go by that had a horrible knocking sound... next corner same sound, no other cars around, its me... pulled off, called it in. idled back to the pits and shut it down. debug points to rod knock on #1. Good news is we didn't destroy the block or the head or anything like that. bad news is we're going to need another rebuild.

so, between the accusump and the oil cooler we had ~6.5Q of good synthetic oil but when we shut the car off we didn't have excess in the oil pan. (have a solenoid valve on the accusump). never saw a drop in oil pressure, and oil temp and water temp were rock solid all day. we have good cooling, we were at 185F for the radiator most of the day

questions to the forum:
a) i thought that we should be able to run up to redline w/o incident. is that true? driver #3 i think took it up to redline on a regular basis. "if its pulling i'm leaving my foot in it" recall we're running '85 or '86 NA cams so they don't die around 6500 like the SC cams.

b) the guy that did our head said that we also should also have "conditioned the rods" we took 4 rod / piston assemblies, along w/ a crank, out of a spare engine. the head guy bought us new bearings for crank and con rods (chinese, one size). we used new ARP bolts in the rods. Head Guy said we should machine 0.001-0.0002 of mating face of con rod cap and then assemble, torque properly and re-machine the resultant big-ends. we did not do that, merely dropped in the bearings and tightened things down per the Toyota manual w/ exception of using the ARP instructions on those bolts. does "re-condition the rods' make sense?

i know, i know, and i kick myself, do the one-size chinese bearings make a difference? should we ahve purchased the appropriate matching toyota bearings?

is there anything we're missing? right now we're pretty disappointed (car fire, holed block, rod knock... 3 failures in 4 races)

right now we're thinking a) we're missing something important, b) these engines are really not up for endurance racing, b) we bought the wrong bearings and if in the future we open up an engine we need to get new connecting rods, new rod bolts, etc. etc...

oh, btw, engine mods: machined head, machined block, MLS gaskets (calc'd 8.9:1 compression ratio), JDM pulley on SC, NA cams. no other mods. pulled great. felt like another MR2 w/ a 2zz couldn't really pull away and we could totally dust a really lightened '85 NA, at least in the straights.... they've got a better sorted suspension

any help here would be great.

You got nearly 7 hours..... but I'd be going with "b", above. Anytime you replace the rod bolts, the rod needs to be re-conditioned. Oil failures typically strike further back then #1. Most common oil starvation is #4 rod bearing. Did you actually check rod clearances?? Or just throw in these Chinese bearings.

Both sets of cams pretty much top out @ 6600 (+ or - 100), but that really doesn't matter... the engine should be no problem going upto redline on each shift.

[yoshimitsuspeed]

You say you didn't have excess oil in the pan. Does this mean the oil level was where it was supposed to be?
This is not a totally uncommon thing for some endurance motors to see but it's not the motor. It's likely a weak spot or a couple in the build.
One thing that can really help is more drainage from the head. You can add external drains like the smallport has to help oil get back to the pan easier.
I have talked to others who have had similar experiences and they also claimed the oil pressure never dropped but I still suspect there could be a lack of oiling. The accusump should help but I have also heard a lot of mixed reviews on their effectiveness.
One thing that should help it moving the oil pickup lower in the pan. I was making a housing that went over the screen and moved the pickup lower but I am thinking about just offering a spacer instead that moves the whole pickup lower in the pan.
There is a reason race cars run dry sump though and it definitely is the best way to protect against oil starvation.

There is nothing wrong with single size bearings as long as they are the right size. How did you guys measure and size them? You said they were Chinese? I would definitely go with a name brand bearing. You could use OEM with sub sizes to get it perfect or you can polish the journals to get each one perfect. If the oil clearance is too big ACL race offer a .025 under which is great. And if that makes it too tight you would just polish it back into spec.
http://www.matrixgarage.com/products/ac ... d-bearings

For a motor like this I would go on the loose side of the factory spec.

If you are running original bolts it's a great idea to at least get the rods inspected and or resized if necessary. Of course the rods are the first piece of hardware I would upgrade in the motor.
If you replace the original bolts you are definitely supposed to get them resized. Many people don't do this and sometimes it works out, especially on a street car but it definitely could have contributed to the failure.
You also need to be real careful who does this type of machine work. I would guess maybe 10% of the "Auto" machine shops out there will actually get everything back into factory spec. Maybe 10% of those are qualified or capable of getting things to a race level tolerance and quality.

[sirdeuce]

Were any of the oil ports or galleys restricted? If crap gets lodged in the crank or block galley it could restrict or stop oil flow. Of course you know that. Even after years of operation something can dislodge, what with the vibration and heat cycles, like a piece of casting flash. Another thing that can offer up problems is changing the oil filter. Dirt can be introduced during the change or a piece of the filter can be introduced to the oil system. Being bearing #1 I bring these to light. On the rods and bearings. Rods don't offer positive centering, unless pinned or sleeved, so just slapping in new bolts or studs without reconditioning can be bad. another thing reconditioning the rods does is ensure a round bore. After years of use the bores can become oblong and create friction hot spots. Bearings; in conjunction with all the aforementioned items, cheap bearings(especially Chinese) have lower tolerances, resulting in sloppy fitting bearings. Did you check for the proper crush? It's possible for the bearing to rotate or spin if it's not properly locked in the bore. Bearing could have rotated enough to block the oil port. Could be the bearing rotated during assembly, partially blocking the oil port. So many things that can go wrong. These are just a few I can think of that could allow normal operation for a while before failure. I've seen all of these as causes of failure. It's a crazy machine!

[sirdeuce]

Another thing, bolt stretch. You said you used ARP, but even they have pieces that fail. Nobody is perfect.

[slow_poke]

clogged ports / galleys: don't think there's anything clogging, but won't know until we tear it down. same w/ spun bearing.. oil filter... we filled the car w/ crappy oil for initial start and did the 60min of accels. drained, new filter added accusump, warmed up. finally, for the race, one more oil change and finally good filter... might have been something, don'tknow.

i didn't assemble but the guys are mechanical engineers by training so they probably would have noticed if one bearing was different than the others...

bolt stretch / assy: we'll tear it down and see if we can see the results... thanks for all the help!

Yosh: the head guy uses these bearings and currently has >6 races on his engine... but he resized his rods. he also said that on these engines you want to restrict oil to the head so he put in a restrctor in the block. essentially forces more to the crank / rods.

accusump. initially we had some trouble w/ it so to ensure it was working correctly we pulled it from the car and cleaned and tried it again. filled it w/ 2Q of oil, installed the solenoid valve, pumped up to 40psi and released the valve. oil shot out of that thing like crazy w/ a stream thick as my finger. shot out a good foot. made a mess... i'm guessing the accusump works great if installed properly, you'd get 5 sec of good oil flow at 40-some psi. more likely 10sec of oil given you won't be totally starved. lowering the pickup certainly wouldn't hurt though.

absolutely agree w/ going to a reputable shop for any machining work...

[yoshimitsuspeed]

The issue with cheap components is consistency, accountability and standards. It's possible that this company has as high or higher standards than ACL, King, Clevite etc but it's extremely likely they don't. It'very likely that if you measured the thickness of 100 of their bearings vs 100 of ACLs you would see more variance in the cheaper ones. If you wanted to take the time to measure each bearing in a dozen spots to confirm thickness and assuming the material quality and consistency was there then they may be fine but generally you would be better off starting with quality bearings that have a name and reputation to uphold.
People have successful builds with all kinds of stuff thrown into their motors but until you look at a big enough sample that doesn't really mean anything.
But either way the level of inspection before assembly is at least as important.

I am not a believer in the head restrictor. There are exceptions to the rule but generally speaking i believe that this was something that was used in special situations on race motors and then everyone decided if a FA motor used it then it must be better for their motor. HKS and similar companies saw the sales potential and started selling them to anyone who would buy.
I have spoken to some race motor builders about this and it sounds like they may be used on some dry sump setups, especially when pumps were so oversized they just moved too much oil. generally speaking though you shouldn't want to reduce oil flow to the head. The big issue is getting that oil back to the pan before the pan runs dry.
The mod also doesn't force any more oil to the bottom end. The oil flow above 3500 RPM is limited by the pressure relief valve. If you restrict the flow anywhere in the motor then the pressure will stay the same and more oil will just flow through the relief valve. Oil that used to be flowing through the head and cooling and lubricating is now just being sucked out of the pan, run through the pump and spat right back out the pressure relief valve.

As for the Accusump, I know they work great in theory but I have heard of many times where people expected them to protect their motor and they didn't. The spec racers at our local private track all ran Accusumps on their 1ZZs. Racers started blowing up motors when they took them to other tracks with big sweepers or other changes in the track. So some of the cars that never leave the track still have wet sumps with Accusump but all the other cars have been converted to dry sump. I do believe if we spent the time to improve the system we could probably get the wet sumps surviving but in this case they just decided to take the safer, easier but more expensive route.

[oldeskewltoy]

As far as draining the head........

[sirdeuce]

As for 'more power', you could try to sneak a 7A block into the mix. There's a guy on this forum that has a set of Belfab rods for sale. I'm sure you could get a low price on the receipt from him. Though the stock 7A rods have proven pretty strong, I'd say to use aftermarket for the extended high RPM periods. If you are running the US spec pistons you compression ratio would be In the 9.5 range and you could run lower boost or tune it for what you got. You can get the 7A block at the wreckers for under a hundy.

For oil return from the head? OST's illustration is about the best. Weld bungs are available as well. if using a threaded fitting, pipe, grind the protruding fitting flush with the inside of the head to reduce restriction. I've seen some install in the valve covers and call it oil return, but that's just vapor.

[slow_poke]

oldskool: love, LOVE the stop motion work!! will consider

sirduece: i like the idea of the 7A. a 1.8L SC. i love it, there's even a note on wikipedia about a 7A-GZE. that said, i'm going to just remember this and try and see if we can get our 4A-GZE working first... any idea on the increase in power? 1.8 vs. 1.6 and 9.5:1 vs. 8.9:1 OST?

right now i'm thinking if the dissembly doesn't point out any foreign matter we'll likely rebuild w/ new rods, rod bolts, oh, and hot tank the block and check it for flash, etc...

[s24a]

If you are cleaning the block, be sure to remove all the plugs before it goes into the marinade, and afterwards high pressure blow out all passages, plus then gun brush the oil galleries until they come out with no residue.
Another thing is after you deburr and clean you can paint the inside of the block with Glyptol high temperature electric motor wire varnish.
This will seal the surface of the block (trapping any particles that didn't come off with the high pressure wash) and also make the block surface smooth so that oil wants to get back to the pan sump faster that a rough surface finish.

[sirdeuce]

Just remember, the thing that gets the 7AGE a bad rap is the cam timing. Get the re-indexed crank sprocket or adjustable cam gears. I've been in a few cars with the 7AGE and they are frikken awesome! Those were NA. I'm sure forced induction would be nuts. Oh yeah, the stock rods hold their own when abused. They aren't as weak as they look. The extra 200cc displacement won't overtax the SC12 and you'd more than likely get more from less boost. Maybe after you get the bugs worked out in the 4AGE or get a good devaluation. It's LeMons! Main goal is to finish! Finish and have as much fun as possible doing it! Good luck!

ACL bearings are the way to go. The mains have a 2/3 oil groove to ensure constant uninterrupted oil feed to the rod bearings. If you want something close get two sets of mains and use just the grooved shells. Feeds oil to the rods 100% of the time while still offering adequate bearing surface for the mains. I've done it in many engines without any main failures with a noticeable reduction in rod bearing issues.

Another thing to do, at a cost of a little power, is using higher vis straight weight racing oils with EP additives. Try for phosphate EPAs over sulphur EPAs. Sulphur tends to have corrosive qualities during time of storage.

[oldeskewltoy]

any idea on the increase in power? 1.8 vs. 1.6 and 9.5:1 vs. 8.9:1 OST?

way too many variables.... but a guess might be in the 170hp range... with torque output of about 150-155#/ft


you might also look at an AE92 version of the C52... the final drive is about 4.1, where the MR2 version is 4.3. This isn't a huge difference... but it might save some engine wear/tear.

[yoshimitsuspeed]

You would gain more power from the compression than you would the displacement because the supercharger is fixed displacement so it is largely regulating the amount of air going into the engine. This does mean that your boost would be lower though. This means cooler air temps and a small gain because at lower pressure the SC will have less air leakage past the lobes. These combined will gain you a little and would allow you to run a little more compression or timing. Or you could overdrive the SC more to make more boost again but honestly on a race car I just wouldn't do that.

Don't take this to mean I don't think it would be a worthwhile change. It should be worthwhile because you will make a little more power at a little lower boost and with a little less heat and more efficiency.