Quicker spool on challenge budget?

Dusterbd13-michael said:

Paul: definitely laggy. Seems to not make any boost or power till aboutv3500 or so. And then its very abrupt. Not linear. 

Pete: the recirc is currently hack, even for me. But itvwas a quickybwith whatvi had on hand. I like your thought process, and do plan to keep it amd ill take your advice. 

Calteg: i have 6 year old rock hard rivals on 15x7 and no traction issues. Which it seems like i should, even at only 10 psi. 

Shinnygroove: thats a distinct possibility with boost leaks. I haven't checked. 

 

 

Everyone: its sounding more and more like ive got some more sorting to do on the setup before i chase improvements.  Apparently its not behaving the way it should yet. Which explains why i was trying to modify it to fix it! Thanks everyone. I truly appreciate this.

You've got some sort of airflow issue going on. PCV, recirculating valve, or a culmination of several boost leaks. I start building boost around 2400rpm 

Boost_Crazy said:

In reply to Pete. (l33t FS) :

I don't see how no valve would be an improvement. With no valve, the air charge would still reverse when it hits the closed throttle plate, but it would also reverse through the spinning compressor. Best case you slow/stall it and have even more lag, worse case you snap the shaft. 

The theory is, turbos are only loaded if they are flowing air.  They aren't positive displacement pumps.  When you snap the throttle shut, with no valve the turbo keeps spinning since it isn't loaded.  With a recirc valve, the turbo is still flowing air.

A couple decades back, someone actually rigged an FD RX-7 to test turbo speed during shifts and the turbo took longer to lose speed when no valve was used.

Of note is that rally cars do not use them.  Response is super important to them, if it helped response then they would be used.  They are also way off the pathological end of the usage curve, with up to 15" of vacuum between the restrictor and compressor wheel, so it may take a 4:1 pressure ratio to make 15psi boost, and since speed makes pressure ratio a lot more than it makes flow, every little bit counts.

I didn't look closely before. That bypass valve is definitely in backwards. It'll work there if it's turned around. I don't think it's causing your slow spool though. A bit more compressor surge, maybe. Turbos don't like that reflected pressure wave off the closed throttle plate, you can hear it. The way the valve is plumbed, it may not actually be opening as there's pressure on the backside of the piston.

This is a pretty well known engine/turbo combo when run with a properly installed recirc. No boost until 3500 is not normal. I don't think we need to get into theoretical discussions of the merits of bypass valves quite yet, there's something else going on. 

Don't forget upstream exhaust leaks as a possible culprit.

So, took it for another drive tonight. 

Boost kicks in about 3k, and buils pretty quickly drom there, in a linear fashion. From off throttle decel to on throttle, theres a noticeable bog/hesitation. 

It revs QUICK from 2k on up to somewhere near 6500. Im only in the neighborhood due to it being a death trap,  so take behavior as such. I did note that the wideband functionality made things better, and i managed to run the cooling fan to maintain consistent operating temperature.  

Its definitely soggy from idle to 3k, and a freaking rocket from there. But i need to check things over closely as i install into the good car as there's only so much i can do here. 

That being said, what else SHOULD i do here before taking it all apart and adding new variables?

Check your base timing and look for leaks post-turbo.

In reply to Keith Tanner :

Umm....

How do I do that with no distributor? I didn't think timing was something to check on these....

Hmm, it's an NB engine right? Depending on the history of the kit, it may have come with a new crank timing wheel that allows you to change the ignition timing.  You may also have the AEM retarding timing, stacking the two of those on top of one another would make for laggy.

NA engines have a cam angle sensor that has to be set like a dizzy, but not NBs.

Also, looking at the pics - does that have the aux injection fuel rail on the intake manifold?
One more question: does it idle okay?

It idles on, but occasionally hangs high idle. Like 1500-2k. But no real reason for it i can find yet. 

Yes, auxiliary fuel rail, but not hooked to fuel. Just hanging out. 

2000 vics motor and ecu, aem fic6 piggyback on it. 

High idle is most likely an air leak post-throttle. Check for cracks around that fuel rail to start.

Dusterbd13-michael said:

Boost kicks in about 3k, and buils pretty quickly drom there, in a linear fashion. From off throttle decel to on throttle, theres a noticeable bog/hesitation. 

Define "kicks in"?  Is that where your butt-dyno feels it, is that where you're seeing it on a boost gauge, or is that where a datalog is showing you > 100 kpa of manifold pressure?  I recommend logging it, then you can compare it to other peoples' setups on this page 

Note that since the turbo RPM and engine RPM are not directly coupled, spool will be slower as measured against engine RPM in lower gears.  So (to make up numbers) if you see 5 psi at 3000 RPM in 4th gear, you might only see it at 3500 RPM in 1st gear.

You say it's a 2.5" exhaust with cat -- do you know what brand?  Is it FM, some other brand, or something boogered together with a stick welder and crush bender?

Is the cat clogged?  What muffler does it have?  IMHO it's worth checking exhaust backpressure -- you can do this by drilling a hole in an O2 sensor plug, adding a few feet of copper tubing (for heat handling), and then a vacuum line to a boost or other pressure gauge.

What is the altitude where you're driving it?

If it has a converter, and if the engine ever had drivability problems were it had a misfire, it may be partially melted down.  This is where metal substrate cats are your friends - they can be IDed easily by having a spiral looking substrate instead of a simple grid.  They don't melt down nearly as easily.

They also can be really, really expensive to buy new.

I am still wondering about your cam timing to be honest, if it's a tooth off then it will drive like that.  My old Subaru was off a tooth and it made no power at all at low speeds.  It was fun that way but not very fast.

So you guys brought up a good point that I didn't know about the turbo reacting differently in different gears. All my testing has been done in first second and third since it's being done in a residential neighborhood. Car has not been above 60 MPH due to violent shaking and Chassis characteristics from the accident. I haven't even tried 4th 5th or 6th in the transmission for anything other than shifting into them and letting the clutch out to make sure they exist. The exhaust is a flying Miata setup with a dual Outlet Muffler that I can't find on anybody's website so I don't know who made it. I'm not sure if the cats damaged or not as I have not inspected the exhaust. Honestly it may be damaged from the accident that totaled the car as well and I haven't seen it yet. Car was running beautifully when it was wrecked so I doubt the cam timing jumped during the accident however it did break the crank position sensor and that was replaced after the accident. It also broke and tore off the intercooler radiator and air intake systems so I had to Cobble those back together for testing purposes.

Show me a picture of the tips, I'll tell you who made that exhaust. We don't sell the duals anymore due to price pressure from ebay junk but they work just fine.

About that crank position sensor - depending on how cobbled it is, that could affect your base timing. It's supposed to be in a very specific location, being a couple of degrees off will mean a couple of degrees of error in your ignition.

Also the readings and RPM I'm reporting are based upon gauge and RPM not but Dino per se. The boost gauge in the car flutters like a hummingbird so I'm doing my best to read it at the average of the needle. It goes to from vacuum to zero with very little throttle input but stays at 0 psi until 3 to 3500 and then jumps to about 5 lb instant on the testing I have done in the neighborhood

In reply to Keith Tanner :

I'll get you pictures of both the exhaust tips and the crank position sensor. I know it was replaced with a new one by Paul and I'm pretty sure he set the gap but I need to look at it closer while I'm taking the picture just to see what's going on there

The gap on the crank position sensor must be good or it wouldn't run :) But I'm more interested in the mount, if that's not in the original location you'd have altered timing.

That big jump in the boost is the interesting thing. Maybe pop off the wastegate arm and make sure the wastegate moves freely. Also make sure the arm isn't binding..... No, that wouldn't cause a boost spike like the one you describe. It would definitely be interesting to see what the boost response looks like in a higher gear.

In reply to Dusterbd13-michael :

Don't trust Paul to have set the gap carefully. 🤪

not sure what im looking for on the cps. It looks... fine?

And the dual outlet muffler may not be salvageable. The one side was broken off in the accident and badly tacked back on with my flux core. 

More will be explored on this car in the coming week as next steps are apparently to smoke test and check timing. And visually inspect the exterior of the exhaust and driveline. 

After the triumph paints and gets reassembled. 

We spray tomorrow 

CPS looks OK as long as the mount is the original and not boogered on with JB Weld in an approximate location. Can't be that far off if the car runs and idles. Gap is fine, that's a yes/no thing.

Exhaust is an old one manufactured for us by Stromung. It's a 2.5" turbo setup and could be two decades old. There's probably no packing left in that muffler :)

In reply to Keith Tanner :

Its loud and unpleasant. But, theres other extenuating circumstances involved. Im reasonably certain there's no packing left either though. Catalytic converter health is a big question mark,  especially with the smoke on startup and misfire i fought upon bringing it back to life. Be interested to see if theres accident damage too.

It's very, very hard to cause damage to an exhaust system that isn't plainfully obvious from a visual eyeballing.

What I would pay close attention to, however, is the notch in the aluminum diff housing.  It's intended to break away so the drivetrain can shift backwards in a hard enough collision.  They can break even in collisions where the engine didn't shift, just from shock loading.

This won't affect boost response or anything, but it'd be nice to know if the rearend is flapping around in the breeze only supported on one side, and is something that should be checked after a crash.

Pete: minor confession time. 

I haven't given a visual to anything underneath the car further than the wheelwells and that was cursory at best. Couldn't even tell you if the exhaust and ppf were bent in half (they're probably not, but you get the point)

After the triumph leaves, ill actually try to at least shine a flashlight under there....