sonny-sil80

so, first of all, hi, im new from BC. been working on Christine for a few years now. had a gt3076r on her. but it was laggy as hell, so i scooped up a tomei b7652 ( gt2871 ) in hopes of it not being retardedly laggy.
well. 2nd gear it spools up right away, makes beautiful power, shoots up properly on the dyno sheet. then third, through to 5th, its laggy as hell and doesnt start spooling til around 4-4500.
ive rebuilt the motor, and im assuming after the rebuild, my secondary butterflies were seized ( my first tune i only made something like 130 hp to the wheels ).
s we disconnected the vac line to the secondary butterflies, and you could feel the butterflies snapping back into place, plugged the vac line. car made 230 or so to the wheels. but it wont go any higher than that.
now my question is. is the lagginess caused by my butterflies not being hooked up? perhaps, some of the flaps are still stuck shut? anything else i should be looking at before i tear the whole stupid motor apart again?
should i route my vac lines so my butterflies read off of boost, and not through the actuator?
in second it was making 240 on a mustang dyno that reads low ( around 290 ) then third 4th and 5th it'll read maybe 215. and the power doesnt come on as nearly as aggressive as second. any help would be appreciated.. havent come across anybody whos had the same issue.
perhaps it could be an injector shitting out on me? air to fuels are relatively perfect. 11-3-11.7 while under boost. just takes a while to get there once im out of 2nd.
i hope you gods can help me out here.
edit: curious if it could be because of running a manual boost controller, my blitz solenoid went on me so i had to go to mbc. wouldnt affect spooling time by 2k revs would it?

Croustibat

Who tuned it ?

Yes your "manual boost controler" is sh*t, bin that thing.

There are 21 different variants of gt2871r, which one is yours ?

I would check these:
first ignition mapping. Who mapped the car ? How ?

second, CAS position. Is the CAS set at 15° ? If not do it properly (you need to fit an HT lead between coil and spark plug, and use that as a reference for your timing light)

Is it fully to the left or right ? If the answer to that is "yes", then your timing belt is out 1 tooth.

I think your MBC cannot hold the pressure your turbo is pushing, or you mapping is wrong. The engine might switch to DET maps because it is detting to death.

sonny-sil80

Racing greed tuned it. .63 rear housing, 60 comp housing. The general 2871 people go after except mine is the tomei version.
I can get the ignition map for you, but I have no idea how to tune and do that shit so I couldn't tell you what it looks like, racing greed did it. Cas is at 15, I have my cas pretty much dead center. I do have the powerbond 25 percent crank pulley, perhaps the "degrees" lines are different that on the oem one? If it couldn't handle the boost pressure wouldn't I see this on my boost gauge? I'm at a solid 14 pounds. I'm about to give up on this car, has to be some explanation..

Croustibat

OK, that gt2871r should spool quite quickly. Your ignition map will not help me, i know my setup and it is not the same as yours (i am running e85 and a gt2560r).

I dont know about the crank pulley either ...

If your timing is right and your car is not having internal problems, it could be your actuator is weak and cant hold the pressure, or your MBC. I really cant say here ...
try doing an ECU check and see which code it tells you. I cant send it to you now because i am at work, but try getting a european 200sx s13 workshop manual to get the procedure for the ECU check (they are called 200sx here, and come with the CA18DET as standard)

try here :
La mini encyclopdie de la RS13

(i know, it is in french ... i think the manual is in english though, try to get the chapter you need )

If it gives you a "no problem" code, try removing your MBC.

sonny-sil80

I just had it at the shop and it threw no codes at me. I have a feeling it could be the WG actuator sticking open after I shift from second to 3rd. Afr's will be beautiful in second, I shift, then go WOT and it'll hit tens till boost starts to build and slowly even out around 11.5. I have a feeling the actuator is sticking, allowing pressure to pass by giving me the richness, and laggy feeling I'm experiencing. Sound correct? I'll be taking my WG off of my older blown t28 and see if it changes anything tonight.

Croustibat

Ok i think i know what is happening .

This is a MAF system; it sends fuel based on the air quantity it measures . Actuator being open should not send more fuel.

a boost leak however, caused by a BOV that does not hold the pressure, will. Try removing your dump if you have one. If you dont, check every hose connexion, because one of them may be leaking on boost.

T28 actuator is very weak, you wont get more than 0.5bar boost with it (unless you shim it, 5mm shims will up that to roughly 0.7-0.8bar ), so it is likely the problem will not appear.

sonny-sil80

The thing is, my car does hold pressure. Under wot in 2nd, air to fuels are dead on 11.5. But in 3rd-5th, when I get on it, it doesn't spool up nearly as quickly as it should, rheres lag and some richness, 10 air to fuels til I get to boosting then it'll rest around 11.5 under boost again. So are you saying after my second gear shift, the bov is sticking open slightly til I build enough pressure for it to seal up?

[email protected]

Based on what? there is nothing wrong with MBC's if it is faulty it wouldnt hold PSI anywhere not just in a certain gear.
I would remove the secondaries all together and leave a open direct path for airflow.

verify Timing and check for boost/vac leaks, try swaping out the gate for a known working one

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MunkyW3rkz Racing

sonny-sil80

Yeah I'm going to remove the butterflies over winter, as I have to do the oil cooler anyways. I didn't get a chance to try my spare gate yesterday, but on my old setup it was running 18 pounds til the turbo seals blew. I'm really hoping its just the gate. If it were the butterflies, second gear would be the same as 3rd-5th. Either the gate actuator isn't closing fully, or the blow off valve is getting stuck. But I'd have a boost leak if it was stuck. In my eyes, the old gate will hold pressure til 5 lbs at least, then the boost controller will manage the spare 10 lbs. This, to me, would allow for quicker spooling, rather than the gate staying full closed til 14 lbs hits. Does this make sense, or am I just being retarded.

[email protected]

if you want to keep a internal gate i suggest getting a new high PSI gate. Many Evo owners swap high psi gates for stock apps.
Verify the MBC is in proper working condition, also try routing your MBC closer to the turbo, I had quicker spool and held PSI beltter when i moved my MBC from my intake manifold to the Turbo Housing.
there is nothing wrong with MBC's. Mine holds 33psi no problem and has seen 40psi a few times. Also used a MBC on a 43PSI set up without any issues for years.
Just cover the basics, The CA's secondaries are wack IMO and would rid them once you get a chance

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MunkyW3rkz Racing

sonny-sil80

Thing is, the gate I have on right now is a high psi rate. The guy who was running it before me has it set to 14 lbs. Perhaps I should take it off and adjust it down to 7 or so?

[email protected]

is it holding psi solid or fluctuating? When you tuned it did you get a graph and does it have a boost plot showing? Of so post it

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MunkyW3rkz Racing

sonny-sil80

Its holding psi pretty solidly. I don't have the boost graphs but I could drop by the shop and get some photos. In second its pretty linear, spools quick. But the graphs for 3rd-5th flatspot til about 35-4k revs then it hits boost.

[email protected]

graph? are you saying your making 1-5th gear pulls?
if so that graph wont tell tell much because the rollers will already be going and the load is minimal if any.

you should be logging it under load as in street / track but honestly if on the dyno doing a 3rd or 4th gear pull it holds fine then theres nothing wrong and this is just a matter of confusion on what the graph/boost plot should look like

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MunkyW3rkz Racing

sonny-sil80

We did seperate pulls for 2nd through to 5th.

[email protected]

why pulls for each gear?
whats the purpose for?
depending on the RPM pick up point there wont be much of a load on it so the boost plot will be different. what dyno was used?

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MunkyW3rkz Racing

sonny-sil80

They noticed the lag when getting up to speed for third gear pulls. It was just to get dead on afrs throughout every rev and gear. Its a mustang dyno. I just want to know if its the wastegate, butterflies, bov or mbc.

[email protected]

well lets start with basic trouble shooting, try running the car without the MBC see if the boost stays consistant, also check your BOV diaphram. make some pulls see what happens. if it stops try throwing the MBC back on see what it does if it comes back then you know its the MBC if it doesnt then both of those items check good.
check all vac lines and couplings, personally put the MBC on the turbo side.

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MunkyW3rkz Racing

sonny-sil80

While disconnecting the mbc will I have to plug the vac line route from my intake to my mbc? Or do I leave it open? Also, how would I check the diaphram. My mbc is mounted on the turbo side, maybe 8 inches from the wastegate. If my bovs diaphram or spring was worn out, it wouldn't show up on a boost leak test would it? I have a feeling its getting stuck upon release of pressure, and doesn't settle back in til I'm making boost higher in the rev range. In my brain this would explain the initial 10.0 afr when I initially get on it in 3rd and above..

[email protected]

you will look for cracks or tears in the diaphram.
plu gup th elines for th eMBC and manifold so that you dont have any vac leaks. basically remove the MBC from between the wastegate and IM and connected it like stock.
leakdown will only tell you on the motor side. you would have to charge the pipes to look for leaks with compress sir and a jig to fit it on one side or another

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MunkyW3rkz Racing

Croustibat

Yes ... you cant see it on 2nd gear because there is not a lot of load on the engine. It happens more on the higher gears because it creates a lot more load.

I think the spring in the bov is too weak and cant hold the boost pike the MBC creates. You cant see it in 2nd because you are already shifting in 3rd when the spike arrives.

And to Santos > MBCs are poo, i dont care if they work or not in your case, they always end up leaking, creating spikes, have no built in security if something goes wrong, and they add more pressure when weather goes cold. Actually that is not open to debate; That is the real downside of using one. The upside is very simple : "cheap boost upping". Every user always forget about the downsides, until they blow up their engine, usually in winter.
They are just an unmonitored boost leak before the actuator command. Nothing beats an MBC when trying to kill an engine.
Now an EBC uses a real closed loop regulation and has enough security features to alarm the driver, or cut boost if things go wrong. It also limits / deletes boost spikes. Advanced ones even have different boost settings, so that if you dont want to burn out in the first gear, and then have more pressure / more sudden boost delivery at higher speed, you can. Some also have an overboost feature.
And no, i dont have one for sale. Mine just has a low/high setting, and i quite like it .

[email protected]

you are right they do not have a fail safe measure but when you have a EMS system in place you can avoid engine failure.
and yes i know about EBC as well as we run a AMS1000 in our racecar.

if you are getting a good EBC then spend the $ on a good one not some $22-$300 crap that always fails

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MunkyW3rkz Racing

sonny-sil80

i'll check the diaphram and keep you posted. the bov is the only thing that makes sense to me. and under a boost leak test it wouldnt show up as the bov does hold pressure, but after it releases, it may be getting stuck, or leaking. unless theres a boost leak test that can accurately show the engines vaccuum/pressure similar to how it is when driving, then i could see it being hard to pin point.
i had mad lag with my 3076 as well, one day just decided to go to 10.0 afr's under boost but would slowly even out, similar to how this set up is from 3rd-5th. im getting further from the wastegate being the problem since the mbc, and the bov are the only constants in both of my setups. as for embc's, i do have one, the solenoid just decided to be a cunt, so ive temporarily set up an mbc til i can source/repair the solenoid.
you guys have been wonderful so far, i really appreciate all of the hypothesises ( the hell is the plural for that? )