Low-end performance?

Q&A regarding engines, turbos, and intercoolers and power upgrades

Low-end performance?

Postby CodingParadox » Thu Sep 16, 2004 5:52 pm

So, now that I have my ignition timing fixed up, the car's actually working fairly well. I still have nasty valve tick that I need to readjust clearance on, and some other small things that I need to fix up, but it's at least in working condition now. However, I have incredibly crappy low end performance, like _far_ worse than my 89 GT (3S-FE.) Now, I realize that this is a far lower compression ratio engine, tuned for a higher revving powerband, but I wouldn't expect it to be this bad. If I'm below 3000rpm, there's just no balls at all. Stomp down on the gas and just nothing happens, it slowly accelerates, even in first.

So my question is, are most alltracs like this, or do I continue to have something major wrong with my car like I suspect? My high end power is pretty good. I'm not as fast as my friend's VR-4, and if all was working well, I should be, since we're both same specced horsepower.

If not, like as I suspect, anyone have any ideas for things I should check? Timing belt we've rechecked two times, that should be perfectly fine. We did ignition timing, and if that's off, it's only by like a degree. Fixing ignition timing was the biggest performance restoration to the car yet. Is it possible that my valve clearance is so fucked that I'm getting this problem? The car is ticking like a beast, so I'm pretty sure that the clearance is something of a major issue right now, but I wouldn't expect it to be killing all my low end power.
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Postby GT4TOY » Thu Sep 16, 2004 8:35 pm

on my stock ST185 if I plant it in first even under 3000rpm it gives you a kick in the pants (only in 1st,2nd,3rd, after that its just to low in the rev range for any power). so I'd say something isn't right.
What boost are you getting at that point?
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Postby RedCelicaTRD » Thu Sep 16, 2004 8:43 pm

Your friends vr4 (im assuming a galant) will be quicker then you even if you are up to par. They have a lot better final drive for acceleration. Take him out on the freeway and you'll show him whats up though. You 3sfe would have had better bottom end due to the head design. It was made for torque. I could punch it down low on my car and there really wasn't a ton of power. Of course I'm at a decent elevation so until the boost kicks in im screwed.
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Postby alltracman78 » Thu Sep 16, 2004 8:47 pm

Do you have a boost gauge?
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Postby CodingParadox » Thu Sep 16, 2004 8:48 pm

I don't really spool until above 3k. If I'm sitting at like 2k in 2nd and WOT it, it'll spool a bit by the time it passes through 3k, but nothing significant. For the most part, below 3000 there really is nothing. If I start from a stop without like 4000rpm clutch-dropping, it'll take it like one and a half seconds of slowly revving up to 3.5k or so, then it's a major kick in the pants.

There's an odd resonance around 3200 rpm, with a band of about 200rpm in either direction, where the whole car is vibrating oddly. Under that vibration peak, no power, above it, power. I don't know if the two are connected or what, but that's odd as well.

And yeah, as I said, I realize I shouldn't have much power down there, but it's kinda ridiculous this bad... :/
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Postby allblackalltrac » Fri Sep 17, 2004 5:27 am

What mods have you performed and what maintance have you performed? What kind of gas do you use? How many miles on the car? Any rebuilds in its history? A little more detail will help in diagnosing your problem. This thread really belongs in the Maintance section...
Got a BGB? That will will help cause theres lots of tests in it for troubleshooting...check the FTP site for peeps that might have scanned in some pages...I would suggest you start with diagnosing your AFM, TPS, fuel pressure and lastly your TVIS (often times overlooked).
Got a boost gauge? Get one if you dont this should be a mandatory install on any FI car and not to be considered an upgrade at all. It plays a vital role as a diagnosis tool.
What boost are you seeing in all gears? Your vac should be in the 15-20HG range at idle...

I don't really spool until above 3k. If I'm sitting at like 2k in 2nd and WOT it, it'll spool a bit by the time it passes through 3k, but nothing significant. For the most part, below 3000 there really is nothing. If I start from a stop without like 4000rpm clutch-dropping, it'll take it like one and a half seconds of slowly revving up to 3.5k or so, then it's a major kick in the pants.


Sounds alot like my car except I have alot of mods so its expected that I will lose some low end...
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Postby CodingParadox » Fri Sep 17, 2004 5:33 am

I've performed no mods. Theoretically, the car's been a daily driver since its purchase 16 years ago. I use 92 gas, though when I got the car it hadn't been driven in two years. I recently drove all the old gas off until it was empty, and have refilled it with 92. That helped a bit, but not as much as I was hoping. 151k miles on the car. No idea about rebuilds, the guy didn't have jack all for documentation. The radiator is the only non-stock thing I've found so far.

I don't have an alltrac BGB, just an 88 celica BGB, but unfortunately that's not gonna help much since this is all engine related. The AFM diagnoses fine (as per the chilton's test method,) TPS also diagnoses functional as per chilton's method, I have no idea how to check fuel pressure, and I didn't think this engine had TVIS... The intake manifold doesn't have a big thing that says "TVIS" on it, so I didn't think it had it. Does it...?

As for a boost gauge, that is my first planned upgrade here. I need to find a good one and then buy it, but yeah, I realize it needs to happen. I have no vacuum gauge or anything, so I can't test vacuum. Yeah yeah, I'm working on that part... :)

I'm really kinda concerned with the resonance thing though, and I'm guessing that's rather telling of some major problem... Any idea about that?
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Postby allblackalltrac » Fri Sep 17, 2004 6:13 am

Yes it does have TVIS.
Give your engine bay a good cleaning with a quality engine degreaser, be sure to cover your dizzy, AFM, coil and starter to prevent them from getting water logged. Do it on a cold motor and have it running when you are rinsing off the detergant.
Check, double check and triple check all vac lines, any that appear cracked, brittle, broken or missing replace them.
Go over as much of the wiring harness that you can and look for for the same as when checking your vac lines. Spray soapy water on areas that appear to be a cause for concern this will determine if you have any shorts - the soapy water will make arking wires more visible. Pull all the connectors off as many sensors as you can reach and check there condition, clean if nessessary.

Sounds like its time for some general maintance. Oil/filter change, new plugs, wires, cap and rotor, air filter, pull the TB and clean that and your intake as good as possible, pull the cat and gut it, replace your fuel filter, replace the filter in your egr vaccum moderator, coolant flush, install a grounding, timing belt, run a really good fuel injector cleaner or have it professionally done at a shop. Look into a product called Seafoam I hear it does wonders but stay away from all those other engine additives. After all that is done add about 3oz of ATF to a full tank of gas and report back.
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Postby CodingParadox » Fri Sep 17, 2004 6:20 am

Oil/filter change: planning on doing that tomorrow
new plugs/wires: plugs are new, wires are of unknown but low mileage
cap and rotor: that needs to be replaced? i suppose i could do that.
air filter: gonna do a completely new intake in a few days anyway
pull the TB and clean that and your intake as good as possible: easily doable. i assume you mean just clean anything off the inside passage of the 3 inches of TB or wahtever
pull the cat and gut it: ... define "gut it", that sounds like remove all the innards... somehow i suspect my emissions test wouldn't like that so much...
replace your fuel filter/replace the filter in your egr vaccum moderator: okay
coolant flush: doing that tomorrow too... running water in there right now
install a grounding: where? it's already grounded in a ton of important places...
timing belt: just replaced it and the water pump and the two drive belts
run a really good fuel injector cleaner or have it professionally done at a shop: any suggestions?
Look into a product called Seafoam I hear it does wonders but stay away from all those other engine additives: yeah, i need to find somewhere that sells it.
After all that is done add about 3oz of ATF to a full tank of gas and report back: what the hell is it about ATF? it's like the universal cleaning agent.
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Postby allblackalltrac » Fri Sep 17, 2004 6:37 am

cap and rotor nessessary: yes
gutting cat: remove primary cat and chisel out the honeycomb webing
will it effect emissions: no
do a search on grounding kits...theres a thread floating around here somewhere
I just looked into the Seafoam product and apparently you can use it in your fuel system, intake system, and engine oil to get rid of deposits. You can find it at CarQuest locations. So taking your car in to have the fuel system professionally cleaned might not be nessessary, however taking the TB off and cleaning that might still be a good idea.
Gasoline is not a very good lubricant adding a few onces to a full tank of gas every now and then helps lubricate your fuel lines, pump and injectors.
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Postby CodingParadox » Fri Sep 17, 2004 6:43 am

Time to find a new cap n rotor. The gutting cat is going to have to wait a bit... I'll put it on my to do list down the line a bit, about the same spot water injection is at... Fortunately there's a seafoam like 2 blocks down the road here, so tomorrow I can hit that up. I think I'm gonna get emissions checked before I start the seafoam treatment. Supposedly it smokes like a bitch, though it does work wonders.
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Postby damselracer » Fri Sep 17, 2004 5:33 pm

seafoam works wonders, its true :)

I've ran it through several high-mileage, highly-abused cars that I've owned or worked on (namely, an 88 Corolla FX with the 4a-c, an 85 Celica GT-S, an 87 RX-7, and an 86 MR2) and I saw pretty immediate improvements in all of them. The corolla was most noticeable- it was getting pretty crappy gas mileage (about 20-22 mpg on the freeway), it was running rough, had horrible emissions, and would diesel like mad when I tried to turn it off (damn carbs!). After running 1/3 of a can down the carb, 1/3 in the oil, and the remaining in about a half tank of gas and driving the piss out of it for about 10 miles, I was able to pass smog, get about 35 mpg on the freeway, and the thing diesels MUCH less when I turn it off. I was sold on the stuff. Beware the cops for those first few miles you drive it though- it makes your car smoke like mad! You should be okay to get it smogged though after you do it- it will only smoke for about 5 minutes.
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Re: Low-end performance?

Postby AwdGte » Fri Sep 17, 2004 8:25 pm

This car has ridiculous acceleration considering its small displacment motor. I attribute it to the few inches of intercooler piping, which is why I want to keep a top mount intercooler, the spool is amazing. Something is wrong with your car, or your expectations, IMO


CodingParadox wrote:So, now that I have my ignition timing fixed up, the car's actually working fairly well. I still have nasty valve tick that I need to readjust clearance on, and some other small things that I need to fix up, but it's at least in working condition now. However, I have incredibly crappy low end performance, like _far_ worse than my 89 GT (3S-FE.) Now, I realize that this is a far lower compression ratio engine, tuned for a higher revving powerband, but I wouldn't expect it to be this bad. If I'm below 3000rpm, there's just no balls at all. Stomp down on the gas and just nothing happens, it slowly accelerates, even in first.

So my question is, are most alltracs like this, or do I continue to have something major wrong with my car like I suspect? My high end power is pretty good. I'm not as fast as my friend's VR-4, and if all was working well, I should be, since we're both same specced horsepower.

If not, like as I suspect, anyone have any ideas for things I should check? Timing belt we've rechecked two times, that should be perfectly fine. We did ignition timing, and if that's off, it's only by like a degree. Fixing ignition timing was the biggest performance restoration to the car yet. Is it possible that my valve clearance is so fucked that I'm getting this problem? The car is ticking like a beast, so I'm pretty sure that the clearance is something of a major issue right now, but I wouldn't expect it to be killing all my low end power.
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Postby Stubble » Sat Sep 18, 2004 4:18 am

At least take your cat off and look at it. If it's plugged, you'll easily see it and it will save you the trouble of troubleshooting the rest of the engine. I don't know what gutting it will do to your emissions, but you can also drill a few holes in the honeycomb for a small improvement.
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Postby BoostJunkee » Sat Sep 18, 2004 4:32 am

The only problem I have heard about Seafoam is on very high mileage engines, Issue being that so much carbon buildup was broken loose that it plugged up the oil pump pickup, and booya instant lack of oil pressure, well, not instant.

But other than that on a couple cars that had never been maintained much, I have heard nothing but good things.
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