7mGTE GT4088 swap, runs, but weird issue? TONs of info, and I've searched.

[nsngarage]

Any turbo'd car i've ever seen will build enough boost to cause the blow off valve to operate. Mine does not at all.. When I drive it, get to 4k it's barely 1psi and it will blow off.. but I feel no boost at all..

The car is leaking a small amount of air at the injector seals.. but it'll build to 7psi before it even starts to leak, so under 7psi, something should be happening.

 

[MDCmotorsports]

I think you keep asking questions you don't want to hear answers to.....

 

[nsngarage]

I can't see how you saying that makes any sense..

The car builds 7+psi through a boost leak test before it leaks through the injector seals..
I've checked timing 100 times as per the TSRM, and it's right..
It will not build anything past 1psi when im on it up to like 4500 rpm..
The wastegate is not stuck open or closed for that matter.
The compression results are listed.

So everything that's been "answered" i've checked and it's all right.

So what exactly are you trying to "answer" for me?

 

[MDCmotorsports]

Explain to me in detail how you have tested the wastegate and turbocharger for proper operation.

 

[honeydew]

"Around 16-19, when it hits 19+ it'll bog and run weird, but go back to 16.5ish (Scary)." Do you mean when you are letting off the throttle and it leans naturally, it'll lean to 19:1 then stutter or bog? as it's decelerating?

I honestly don't know where the PSI hangs with a MBC turned all the way down on a GT4088. Good god it could be anywhere. On a CT26 it should read around 6PSI. With my 57trim turned all the way down it hung around 8-9PSI.

I have a feeling you are breaking in your engine and, rightfully so, being very ginger with the throttle. What I mean is you are not Full throttling 100% to 4000Rpm. You are being easy on it, yes?

When I drive my Supra easy for gas mileage reasons it feels very heavy and I can drive it so it doesn't spool at all. In fact when I was in "Limp Mode" from a weak HG for a few months I would keep an eye one my gauge and made sure it never went over 1 or 2 PSI.

It is a bigger turbo so the spool will happen later. the CT26 came in quick but died around 5600-5800Rpm full throttle on a stock set up. When I had the Lexus upgrade with a 57trim into my CT (Mind you I had 680's, duel walbros and a regulator, SAFC and Wideband.) the spool came later but stayed well into 7000Rpm full throttle.

Because you are not pushing your car yet I wouldn't worry about the lag and apparent lack of power. Break in your engine first the way you feel comfortable. Then when you are 100% in on the throttle you can have a better perspective of the complete system.

I think at this time you might be OK to full throttle it for a short time once complete warmed up. You really do need to throttle 100% until spool to really see how it'll react.

Compression on 1 3 and 5 seems a bit low? anyone is that normal?

Edited to add: You had a issue with leaks at both ends of the IC? what IC are you using? Stock? What Pipe fittings are you using? Gearclamps? Blue cuffs?

---------- Post added at 12:46 AM ---------- Previous post was at 12:36 AM ----------

Sorry I didn't notice there were several pages to this thread. I only read 1st page. whoops. BUT I think most of what I said can be salvaged.

He is saying he "Get's in on it to 4200Rpm" before he backs off in fear of damaging new engine. With a 4088 I probably would be pretty paranoid too. Considering the Air/ fuel system has not been upgraded you will hit fuel cut if you revv much past 5000rpm anyway. Be thankful for that otherwise you would just detonate and blow up your engine.

A wastegate problem. as in being too small would creep his boost upward, not give him a lack of boost.

Even a turbo charger that has been eating something and lost most of it's inital blades will still spool auditorily and make some boost.

 

[nsngarage]

Well the entire kit came from funkymonkey... with very little mileage on it... the wastegate spring moves like it should and I can hear the turbo "spooling" or at least trying to like it should.. There is ZERO shaftplay and there's no smoking at all.. except for unburnt fuel when I rev and let off.. my next step is to block off the wastegate and run it to see if it will spool boost...

Honeydew - yeah it'll lean naturally when i let off after a rev.. Since my original post I've gotten into it a bit more.. it just seems to labor to 4k even, and it'll build 2 psi of boost, without the feeling of "pull" which from a 4088 should be there.. if i stay in it at 4k and 2 psi, I feel what I'm assuming is fuel cut happening already..

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[nsngarage]

Im also putting a walbro in with the afpr from aeromotive and the lexus afm along with 750s.. if nothing seems to change after that im going to do a megasquirt setup and ditch the afm for a 3 or 4 bar gm map sensor..

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[honeydew]

No Bud I'm telling you the lexus AFM can metre so much more air than our stock ones can. Huge difference, and of course, when you add the fuel sending system with a injector that can handle the flow, well, it's just an open door.

750's will be more than enough, fixed forever. A regulator, a reliable regulator will be necessary.

Honestly IMO, There is nothing wrong with your car at all. It's reacting like it should, laggy turbo spool, and when it finally does spool the set-up can't support the A/F needs. Put in those extras you just mentioned with a reliable tune, you are gold.

It's actually almost genius to omit the fuel and air when upgrading a turbo cause your ECU will fuel cut before you blow anything up while you are breaking in the new engine. Ironically genius.

 

[nsngarage]

I really hope that's the problem.. So the GT4088 and the stock afm and injectors will act just like I'm saying?

Even without being in boost being sluggish?

 

[honeydew]

Well ya. You are not revving past 4200Rpm (or about) correct? The 4088 is pretty big from the CT26. I wouldn't even expect that to spool until after 4000Rpm and 100% throttle. With no A/F support it'll fall on it's face once it begins to spool. Whatever you do don't push it past there even if you are able.

OMG the car is soooo sluggish out of spool. Like I said, I have honed a skill of driving it out of boost and it's slow and feels so heavy. Great gas mileage though.

---------- Post added at 01:49 AM ---------- Previous post was at 01:45 AM ----------

It's almost like where the CT26 ends it's lifespan in the powerband the GT4088 is just getting started.

 

[nsngarage]

What turbo and mods are you running? I've read that people with the GT40 series turbo's will start spooling at 2800-3000 rpms, and im nowhere near that.. Would the fuel/air restrictions cause slower/later spool also?

 

[honeydew]

GT40 series like a GT4094? Bull. Straight bull.

I HAD a 57trim impeller wheel on my CT26, same exhaust wheel, tiny little guy. Given that, you would think that since it's operated by exhaust I would be spooling very close to stock... Not so. The 57trim inducer is bigger, but not by a huge margin to our eye. To the laws of physics it really is exponential.

With the GT4094 the low end of the gears (@ 100% throttle) are quite unremarkable, and unremarkable for what seems like a long time. But as you come out of vaccuum and hit boost around 4000Rpm you feel it pulling. Then things gets really spectacular once you are making about 5-8Lbs +.

I think that's why alot of drag guys like these turbo's because you can establish SOME traction in the low end before things gets crazy.

Yes and No about the A/F situation affecting the boost. Yes, your car cannot suck in enough air to support that turbo. Yes, your car cannot suck enough Fuel to support that turbo. No, Your boost should not be affected because it never has a chance. Once your big turbo makes some compressed air for the compression chamber, the AFM and Fuel system cannot keep up. Fuel cut.

 

[nsngarage]

So im on par then once I get the right mods... basically as soon as the boost is starting im backing off because im trying not to beat on it yet lol...

So it seems like I may be worried about nothing.. ill know soon.. next few days the other stuff is going in

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[honeydew]

All I'm really saying is that it's shortsighted to think that a big turbo is the end all and be all of making speed. It's a piece. One step of several or else the turbo is useless. The turbo is adding denser and denser air, but with no fuel (and without a bigger AFM to get the air coming in) the dense air is completely useless and counterproductive.

You really are putting the cart before the horse. Do everything for your engine to work properly then if you still have a problem (which *teehee* you might have) let us know.

Kinda shocked it took 4 pages to realize he has a 7M-GTE stockness with a GT4088 and NO SUPPORT FOR A/F.

 

[nsngarage]

I see what you're saying, but to me, the car runs slower than the NA did even without boost.. that's the entire point Im trying to make..

I know to reach full potential of a bigger turbo you need supporting mods.. I am just waiting for all that stuff to come in, but before that I drove the car, and it seemed wrong to me.

So, I'm not sure if the comments are aimed toward the "smart" side of things, but if they are I don't appreciate it, I appreciate the help on everything else you said.. Just seems to me that the motor should be a little faster even before the turbo spools.

Ya know what I mean?

 

[nothingbetter]

did you check the valve clearances when it was rebuilt

 

[boostcraver]

Cam Timing NOT Ignition timing....:nono:

What he said^^^^ When setting the cam timing you should first set the crank to 0* TDC, cyl#1. Next, line up the timing marks on the cam gears with the marks on the upper rear timing cover. Route your belt and get it READY to be tensioned. Once you are to that point, turn the cams about a quarter tooth past the mark clockwise (IOW, just slightly past the mark). When you apply tension to the belt, it will pull the cams back to the marks and your CAM timing will be set. I drove my first supra with a slight misalignment of the cam timing for about a week after a headgasket replacement and experienced similar sluggishness. Once it was corrected though, I had power again. Might be something to look into, since you have only described the ignition timing being checked. Yes there is a difference between the two. Hope this helps.

On the subject of GTE vs. N/A, you have lower compression from the factory in the boosted motor, so it won't naturally tend to be a very "zippy" motor off-boost. I've had four 7M powered vehicles and they all were less than impressive to me off-boost.

 

[nsngarage]

I've put the Crank at 0 and reset the cams according to the marks on the back of the upper timing cover quite a few times, when I roll the motor over and line up the crank on 0, the cams are straight up pointing at their respective marks.. I'm still lost as to what my problem is.. I'm starting to feel like it's a sensor or an ecu problem for some reason..

I'll be able to eliminate the ecu problem soon as my shop started into Megasquirt standalones.. So I'm sure one of those will end up in my car soon enough lol

 

[Nick M]

0 on the crank pulley is not straight up on the cams, assuming you mean the damper, as the pulley isn't marked. Read the TSRM. Their procedure isn't needed, and it isn't that hard. You have to have the damper off, and have the crank at 0. Of course, the crank timing pulley has no mark, so you have to mark it before you pull it off. Later Toyotas are marked. Our's isn't.

 

[nsngarage]

The crank timing pulley only goes onto the crank with a keyway yes? I'm looking at the TSRM and I don't see how to check that specific part for 0, it points you to the Damper