**CHALLENGE** - TURBO LAG TEST using a log
- Thread starter coker6303
- Start date
I'm scared to see mine. I bet 10 seconds
Spray her like a man!! Lol :happy2:
Boost is a measure of restriction. The turbo fills up the engine and when there is more air in the engine than it can take boost is created. Different size turbochargers will flow different amounts of air true, but if you are measuring boost and not exhaust back pressure between the engine and the turbo, the turbo is not your restriction point, the engine is. So take a stock turbo and compare it to an aftermarket turbo. They both can make 20 PSI. How quickly is a good question. Now let’s shoot for 50 PSI. The stock turbo won’t make it or live at that level for long while the aftermarket turbo can. That is why the aftermarket turbo will make more power than the stock because there is more air available. The bigger turbochargers move more air so they should in theory fill the engine quicker and create boost numbers in a shorter amount of time. The other side of the coin is that bigger turbochargers have heavier wheels and take more time to get spinning so there is a delay in making boost, but once rolling they will make more of it. Cool thread! :thumb:
5th, hold 1500rpms steady as possible (not 1599 lol) and then jump in it without down shifting. Then highlight the log from the start to 20psi gain on map reading
My truck will not complete this. I have my trans calibration set so that I will need to be at 2400 rpm when I crowd the throttle or it will downshift. That means roll into it at 80 mph.
And if I do lightly crowd the throttle I will be doing 80 by the time it hits 20 psi.
Now if I am doing 55-60 and press pedal 75% I will get 1 downshift a cloud of smoke and 20 psi in a decently reasonable time ( I will try for a log and vid).
In the same situation if I go 100% pedal I get 2 downshifts and basically 20 psi in less than a second.
The only way I could perform the test is with a stock trans cal. Which is really awful to drive on because the truck won't downshift.
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Id love to participate but I'm not very good at logging. If I lock my truck in fifth with the converter locked and lay into it, it will be tomorrow before my charger lights lol. In fifth it doesn't light until about 80mph 1800 or so rpms. Believe it or not my truck is very streetable with the trans tune I have though but it downshifts with very little throttle input.
I don't mean to speak for Russell, but I think that's the whole point of this thread. Everyone getting these big fixed geometry turbos are saying they "spool like stock". I personally find it a little hard to believe. I've been around larger turbos (even modified stock ones and bigger VVTs) and never saw one that I thought spooled anywhere near as well as stock. Now you two and Brian are saying your turbo won't spool well enough to complete this test. Try it and post the results. You can make a tune that will hold in 5th gear for this test if you want to do it.
Exactly Josh! That was the reason I suggested doing the test this way instead of a roll. Just because you can tow with these big singles does NOT mean they tow well. I would never want to tow with a truck that had to downshift at 60mph then take off like a rocket.
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Ok josh I will lock it 5th and do a log.
I can tell you now its gonna be a rolling freight train that video will only do justice. Like a gallon of fuel to light it.
A setup has to be complete.......as in I picked a cam and head port sizr, compression, timing and fuel pressure trans cal and tc stall.
Like dmacchris brian and the rest of us have found. With the right combo these trucks are amazingly streetable.
Towing is a chore but can be done.
Not to mention my trucks exhaust noe sounds more like an alchohal dragster than a diesel as I click off gears.
I would not say spool like stock at all.
But our point is the trucks are responsive they are also a completely diffrrent animal. Does that make sense Josh?
from mobile
I can tell you now its gonna be a rolling freight train that video will only do justice. Like a gallon of fuel to light it.
A setup has to be complete.......as in I picked a cam and head port sizr, compression, timing and fuel pressure trans cal and tc stall.
Like dmacchris brian and the rest of us have found. With the right combo these trucks are amazingly streetable.
Towing is a chore but can be done.
Not to mention my trucks exhaust noe sounds more like an alchohal dragster than a diesel as I click off gears.
I would not say spool like stock at all.
But our point is the trucks are responsive they are also a completely diffrrent animal. Does that make sense Josh?
from mobile
If I pull a mountain with a trailer it has to be fully lit at 80 mph. So yeah it is a vhallenge. Od lockout and manual 3rd etc.
But I can keep egt's below 1200.
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I completely understand, but streetable is a very subjective term. I wouldn't want to drive a truck that has to downshift on every hill, but to some, that isn't a problem. I've driven several different turbo combinations, and I know they build boost quickly once they start to light. The question is, when or how long do they take to start to light, and how does it compare to a stock turbo? I think that is what we're after here.
