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1984 245T mLPT B274FT Project

Some pretty sweet torque for pump gas, man.

Do you have any particular power or 1/4 mile goals in mind?

Do you have a way of measuring exhaust backpressure? Looks like maybe boost/torque might be falling off - as it is there's no point in even tuning at higher rpms IMO, torque and HP are falling off pretty hard... as it is you wouldn't pick up any power spinning to to 7k that's for sure. Maybe you're dropping boost intentionally due to fuel limits though...

I'm interested to see where this goes.
 
Captain Bondo said:
Some pretty sweet torque for pump gas, man...
Maybe you're dropping boost intentionally due to fuel limits though...

I'm interested to see where this goes.
Click to expand...

He said that right now his limitation was fuel pressure, from the pumps being insufficient (because the injectors are only at circa 78%)

Once he gets a pump that's better equipped to handle those sorts of HP numbers, he'll definitely be making serious HP and Torque well into the 7000's
 
Last edited:
amerbritcan said:
He aid that right now his limitation was fuel pressure, from the pumps being insufficient (because the injectors are only at circa 78%)

Once he gets a pump that's better equipped to handle those sorts of HP numbers, he'll definitely be making serious HP and Torque well into the 7000's
Click to expand...


:doh:
 
Captain Bondo said:
Do you have any particular power or 1/4 mile goals in mind?

Do you have a way of measuring exhaust backpressure? Looks like maybe boost/torque might be falling off - as it is there's no point in even tuning at higher rpms IMO, torque and HP are falling off pretty hard... as it is you wouldn't pick up any power spinning to to 7k that's for sure. Maybe you're dropping boost intentionally due to fuel limits though...

I'm interested to see where this goes.
Click to expand...

Cappy,

Nope, no particular power goals. Just whatever it will make.

There is no special provision in my exhaust set-up to measure back-pressure. You think maybe the GT30R is choking the engine? I'm not at all sure that the graph above peak power and torque RPMs has much meaning at this point until I fix the fuel issue and try again. As I mentioned the ignition timing levels are not optimized yet nor (obviously) the fueling in these upper ranges. We're not going to refine the tune all the way up to 8K if it's not making any more power there. If I end up needing a bigger turbo, I'll get one.

Paul
 
"If I need a bigger turbo"

hahahaha, its going to be fast regardless. Need to figure out where you want to stop ;)

http://www.atpturbo.com/root/maps/gt30r.htm

That's the flow map. I would actually have expected it to spool a little faster, I imagine that's something left to be ironed out in the tune.

If you do decide to go bigger, I would recommend an HTA35R from forced performance.. you get a bigger turbo but the spool up will be somewhere inbetween what you've got now and a regular 35R. generally those are good to around 650 or so hp, and the area under the curve is on average broader than those with regular 35r's.

Still, be interesting to see what it does with the system sorted and all tuned out.. I bet you won't want to mess with it for a while once you get to that point.
 
For what it's worth, YLD244 runs a dead stock motor, uses a GT35R, but a mid sized 35R, it comes on full boost by 3k and runs motec fuel injection and ignition, so i'd say a GT30 would be a limitation on a motor almost half a litre bigger with twice the number of valves and air flow.
 
VQ said:
For what it's worth, YLD244 runs a dead stock motor, uses a GT35R, but a mid sized 35R, it comes on full boost by 3k and runs motec fuel injection and ignition, so i'd say a GT30 would be a limitation on a motor almost half a litre bigger with twice the number of valves and air flow.
Click to expand...

Reviewing the dyno again with a little more perspective, something is off with the spool up.

It spools like the same as my T67.... that turbo should be all in almost 1000rpm sooner than it is IMO... maybe the dyno doesn't load it up very much and it spools better on the street though. I missed what sort of dyno it was and what gear the pulls were done in.
 
Done tuning for now

Finally got my turn on the dyno again.

Chart is posted below but it's not significantly different from last time. Last time's problems are fixed: fuel pressure is stable at all rpm and load levels.

This time's problem is clutch slip. Started to slip somewhere past 4500 RPM, so my power peaked at 4900 that run and no more power tuning runs were made. I could put a new clutch in and go back, but it's pointless since I will never be able to make the clutch slip on pavement with this wheel/tire combo. Disk is sintered metal 4-puck, PP is my old Centerforce.

I won't have complete maps until Saturday but tuner said it has a safe tune, only moderate ignition advance, injectors well within their limits. etc. It's now being tweaked for drivability (cold start, part throttle accel, etc.)

461 WHP at 4900 rpm
508 WTQ at 4500 rpm

Turbo is GT30R with .82 A/R turbine. Spool-up still looks the same as last time on the graph but both hp and torque build noticeably quicker than last time. I haven't driven it yet but tuner told me it has no discernible lag on the street. We'll see.

Dyno still Dynapack. Gas still Sunoco 93. Note ambient air temps during run, not sure how much affect that had on results. Last dyno figures posted were obtained when it was 15 degrees cooler.

V172710.jpg






Next steps are hood repair from where engine is trying to beat its way through, and some better kind of engine stabilizer.


.
 
Great to see you're back to testing! Still seems like something's off though eh?. I think the hotside is really big for the cold side maybe - so it spools kinda slow but then the cold side chokes it.

What are afrs like in the spoolup range?
 
pwschuh said:
Hi Kenny,

What do you mean when you say "spool-up range"? The graph I posted includes the AFR's from 6 psi and up. Did you mean from vacuum up to 6 psi?
Click to expand...

No sorry my bad, i didn't pay enough attention. I meant in the 0-14psi region. AFR's look plenty aggressive especially for pump gas - I was thinking maybe it was overfueled on spoolup but that deifnitiely isn't the case. 14.0 is a very lean spool.

Only thing that doesn't seem right to me is it's getting fatter after peak torque/power...
 
How have I never seen this car before? :oops:

This thing is amazing! I've seen you post plenty before, but somehow never saw this thread. . .

All I can say is WOW!
 
Captain Bondo said:
Still seems like something's off though eh?. I think the hotside is really big for the cold side maybe - so it spools kinda slow but then the cold side chokes it.

What are afrs like in the spoolup range?
Click to expand...

On the flip side, it also keeps the hotside significantly cooler and alllows for more time spent at high rpms without excessive heat buildup. That and a slightly smoother boost curve......... just throwin that out there.
 
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