T3 T4 Hybrid Turbo OHV

Well I got tired of the 4.0 ohv not having any power on the highway climbing the hills on the 62 and having no low end in 4x4 high offroad, especially now that I have a pickup with a 5.7 v8 in it..

I've been lurking for some time since I've been kinda busy with work but, I got my hands on a Turbonetics T3 T4 hybrid so it's project time. It has the .48ar T3 turbine and a f1-57 trim T4 compressor. I expect this thing will spool FAST but I am not making any claims to being too familiar with forced induction..worst case scenario is there's a problem I can get a higher trim turbine.

I plan on having it live just behind and to the right of the alternator after doing test fitting. Its snug but should work nice to draw through my snorkel set up and for routing the exhaust.

Now, I have a concern about drawing through the stock airbox with a K&N drop in.. will this be too much suction and cause oil to get past the center housing seals?

If I hit full boost before highway cruising speed will that boost still be effective once in the higher RPM's? ie: is 7lb boost (where I plan to limit it at) at say, 1500 rpm still 7lb boost at 3k rpm?

Anyway, thanks in advance for the guru advice and input. I'll try to post through the project and get some pics up since everyone likes pics.

'merica

 

[Caejxr]

Impatiently waiting and cursing fedex for taking "so long."

 

[Caejxr]

Wire bound tuning guide showed up today from Don LaSota. 114 solid pages of textbook type material. Guess I'll get crackin on getting smart since I have a few days until the usb key shows up

 

[Caejxr]

Finished reading the book today while the network and email were down at work.

Lots of good info I will reference as I go and it's mostly layed out in order of what to tune first. Still some to be desired.

Seemingly my most difficult challenge will be tuning the spark and fuel once the maf curve flatlines at full boost. Maybe someone has some experience in this part that can chime in with some tips?

Not too sure yet how to compensate for the fuel when the curve flatlines or for the dropoff in load that will add spark. Obviously the latter will require adjustments to the spark tables beginning at where the MAF input, boost, RPM and Load all cause this.

Still trying to wrap my brain around tuning the MAF once boost makes it flaline at 7lb. The textbook said to group the data points close together, easier if I can move them manually on a graph... it'd be easier to understand if I could get into the program yet....or if I should just go with adjusting the base fuel table to be richer at the higher rpm's to avoid leaning out. Input to which is preferred?/why

I don't want to use a fuel adder (if one is in the program) because I do not want to deal with re-tuning any time there is a change in the weather,altitude,temprature etc. That'd be dumb for my purposes.

...this books taught me enough to be dangerous not sure about being effective yet.

 

[Dono]

Im the wrong person to be commenting as I have no knowledge here. Take my comment for what its worth (Not much).

But, even when boost flatlines at 7lbs, the maf will continue to read the volume of air going thru it. As rpm's increase, the volume of air increases. The increase in air flow should allow you to tune a/f. Im sure there are many other tricks. Do you have access to the SCT forum yet? I'm sure there will be a thread on this.

 

[Caejxr]

Im the wrong person to be commenting as I have no knowledge here. Take my comment for what its worth (Not much).

But, even when boost flatlines at 7lbs, the maf will continue to read the volume of air going thru it. As rpm's increase, the volume of air increases. The increase in air flow should allow you to tune a/f. Im sure there are many other tricks. Do you have access to the SCT forum yet? I'm sure there will be a thread on this.

I think you're right, I'll double check on the SCT forum and see if there's anything contrary but I think the MAF flatline at full boost only applies to WOT as at that point the volume of air being allowed/blown in is a constantwhereas with acceleration it's increasing as RPM's go up like you said. Probably was just over thinking it and erroneously applying a WOT concern to acceleration. Ill report back.

 

[Caejxr]

Confirmed...my concern really only applies to WOT. Boost comes on so fast even under 1/2 throttle it should make things interesting for tuning..

So,
At WOT at full boost the MAF sensor will flatline due to the volume of air passing the MAF remaining the same. Under WOT and full boost is fine because as variances in the throttle allow more or less air pass the MAF and enter the engine it changes fueling as well as other parameters based on what it senses. (Given impeller spinning at a given speed will only move a certain amount of air and only build so much pressure within a given size chamber. <- which explains the drop in load. Load is a measurment of air in the engine. So as an example..if at say 3500 RPM and 7lb boost at WOT is a load of 1.0 (100% load) as RPM climbs load will drop because the turbo is not pushing any more air into an increasing frequency of combustion cycles...so at say 4500 RPM load may drop to .870 or 87% Load... If I'm not mistaken, this makes the PCM think engine going rich so it adds spark as load decreases, tuned incorrectly this is where detonation can come on very quickly and become catastrophic. Which brings me back to the best way to attack it in the tables. Maybe locking spark to a given value at the RPM's where MAF is flatlined and Load is dropping and shooting for an A/F of 11.3 or so at my max RPM to keep the mix richer in this scenario?

 

[Dono]

At wot, the maf should never flat-line.
If your accelerating, more air is passing past the maf as the rpm's increase (Think an air pump that's spinning faster). When you shift to the next gear, rpm's decrease causing less flow across the maf. My 'over-thinking' comes in when I try and understand how the maf knows how 'dense' the air is (Boosted, pressurized).

If your maf flat lines, it could mean you are 'pegging' it at max. That would mean you need a different maf and/or maf tube.

Once you have the software you will be able to sort out the timing. I know there are tricks (That I do not know) to tuning turbo that makes your life much easier. Question is, how do you find out the tricks without living the pain?

 

[Caejxr]

At wot, the maf should never flat-line.
If your accelerating, more air is passing past the maf as the rpm's increase (Think an air pump that's spinning faster). When you shift to the next gear, rpm's decrease causing less flow across the maf. My 'over-thinking' comes in when I try and understand how the maf knows how 'dense' the air is (Boosted, pressurized).

If your maf flat lines, it could mean you are 'pegging' it at max. That would mean you need a different maf and/or maf tube.

Once you have the software you will be able to sort out the timing. I know there are tricks (That I do not know) to tuning turbo that makes your life much easier. Question is, how do you find out the tricks without living the pain?

I guess that makes sense. Doing the same thing faster.

 

[Caejxr]

Uploaded the base tune tonight. Looks to be basically the stock 91 octane explorer tune file with the BA5000 Maf tables from a well tuned mustang file, 36lb injector tables, and some edits done to the top ends of the fuel and spark tables.

Idle runs a little richer than before but not where I want it. Still seeing 15-17 at times at idle but I'm targeting 13-14.

Most of the program ive noticed so far requires math to transfer logged values to target table values..I like the functions I can enter zero into to turn them off...like the auto transmission function and the associated codes. It's simple multiplication/division but still...not my strong suit but theres a built in calculator....Richened up the base fuel table and cold start table at .1 and .2 load under the 750 column for idle but ran out of time for tonight I'll upload it and log it in the morning should have done the trick.

 

[jd4242]

Good to see progress. .think you picked the right path..i cant help any as far as advice,all my tuning is done on dyno..but im following

 

[Caejxr]

been putting hours into this and slowly the afr's are getting where they need to be and i'm actually able to drive it 1st through 3rd mid throttle right now.

Still too rich but the goal is to get part throttle where its not so rich it bogs and refine it from there to reach the commanded af a lot of discovery learning taking place so It's taking longer than it should but its going. Every re-tune and data log I do gets me closer.

 

[Caejxr]

53 tunes later and some fine tuning left to do I've got it driveable up to 3 lb boost. It's a bit rich still through the rpm range but its driveable enough now where with the wife copiloting and watching the AFR I'd feel confident taking it on the road to get full boost tune it in then try a wot pull.

 

[Rick]

Sounds like you are on the right track

 

[Caejxr]

Thought I'd be nice to the environment and keep the breather on the fill cap hooked up. Ended up pressuring the crank under boost enough to be squirting oil out the base of the dipstick. I capped it off to hopefully solve the issue could have gone with a check valve to only allow vacuum through but this should resolve the problem too. BOV is on the way not too cause I have compressor surge now that the exhaust is solid.

 

[Caejxr]

Alright So doing more reading and digging around my engine I think I need to put a check valve into the drivers side valve cover vent. Looking at the intake runner near the brake booster hose the one goes down into the valve cover is wide open to boost. Would it be a vac leak if I capped the intake runner there and vented the valve cover?

 

[Dono]

Im trying to remember the factory 4.0 ohv routing.

I 'think' you would have an issue with the pcv valve. When not under boost, the vacuum would be pulling air thou the motor from that filter. This would be introducing un-metered air (a vac leak, like you suggested) in to the intake.

 

[jd4242]

You would have to cap the line on the intake tube side,coming from oil fill neck,then place filter on oil fill neck also..both sides would need filters and both vacuum sources would need to be capped..

 

[jd4242]

But there is a check ball in the pcv line on the driverside. .its only open doing vacuum. .there is not one on the oil fill neck line though and boost can be introduced there..

same time you really need to worry about all the other items that may be boost sensitive coming off the intake manifold,like the FPR..too much boost can blow the diaphragm out and fuel could be sucked back down the line when vacuum returns..could is key word..

 

[Dono]

I agree JD. There are a few notes on this though.

I guess is depends where the turbo is on the inlet side.
does the intake air go Mass air meter, fresh air inlet to motor, then turbo?
We always want metered air.

Also, does the pcv valve seal under boost? (the 5.0 one doesn't, I had to substitute a different pcv valve from a vehicle that was factory supercharged).

 

[Caejxr]

JD's comment on breathing both of the hoses seems right. With the filler breather capped crank gets boosted still. So the check valve in the cover still lets boost through. It may cause a vac leak if their vented but it isnt one causing any noticible issues while I am data-logging. Right now I just want to get oil to stop blowing out. I have the tune really close now and want to test it on the hwy so I can get more data but I dont want to do that loosing oil. BOV should be here within the week.