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3" full exhaust hurtin turbo spool?

Old 05-16-2018, 05:31 PM
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Default 3" full exhaust hurtin turbo spool?

So Ive been messing around with my setup, 5.3, ported stock heads, 218/228 blower cam, CX 76/65 .81AR, 3" crossover, 3" dump into a resonator into a 3" catback with dynomax ultraflow SS muffler and dual 2.5" tips (sleeper quiet). Im noticing in my logs that boost seems to start in early like 3k but doesnt full boost till later. Its a 2004R with a 2400 billet converter stall and 3.55 rear gears (converter feels to be alittle loose maybe due to the low end boost power). The problem is that I want it quiet (only street DD driving). Im trying to get some good data but I can't seem to get enough load on the engine/turbo to get it to spool quickly. I have 275/40r18 summimoto HTRZ IIs (less than 1k miles) and the power just blows through them on the street. Most of my logs I can't get more than 50% TPS without smoking them and thus no load and no logged turbo spool. I'm looking into getting some lightly used MT streets in a 305/35r18 and seeing if I can get some traction with those. Log resolution isn't the best as it shows 200-500rpm breaks but it is what it is. Attached is a log of prob the only low rpm to 5k log I have, you can see the boost starting in the 3K range and full boost in the 4k. THis should spool like 2500-3k and be all in 500rpms. I can only assume that my log isn't accurate as I can't log the engine without tire spin so I dont know the whole truth. But its been brought up that my full 3" catback is killing flow and causing slow spool. I can't dump the exhaust except under the car, i could do a cutout but thats after like 6ft of 3" DP. Thing is that I dont want to have to open the cutout or be loud to spool... maybe I just need to delete the resonator (doubt its hurting flow its 3" straight through perf core). Or Run something like a SLP loud catback style with a single muffler in the intermediate pipe? Again I dont want it "loud" tho lol.

Thoughts? Think its just traction and need to get that before making a decision?

heres the log showing RPM/MAP/TPS%
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Old 05-16-2018, 05:53 PM
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3" crossover will kill spool. change it to 2.25" and prosper.
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Old 05-16-2018, 06:50 PM
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You need to go WOT. Rolling onto it like you did in that log isn't going to tell you much really. I run a 2" crossover on my junk.
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Old 05-16-2018, 06:52 PM
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Is that log in third gear? If not try it there. Just go WOT who cares if it's spinning it will give you better data than you're getting at 50% tps.
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Old 05-16-2018, 06:58 PM
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Might be traction? I had a bunch of inaccurate logs while spinning(low psi and rich spikes).

I ran my best trap through a standard 3 inch exhaust to corsa dual w/ bullet resonator welded in the I pipe. Didn't get a chance to open the cut out for a back to back test but I think it was making over 600rwhp.

Just noticed you weren't even WOT.
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Old 05-16-2018, 08:43 PM
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Originally Posted by LILHEMI View Post
3" crossover will kill spool. change it to 2.25" and prosper.
wish I could. The way CX designed the crossover connection to the pass side log gives me no real room to modify. I would need a 3 to 2 vband adapter and even then I dont think Id have enough room to clear the tensioner. Ive thought about it many times but it would be a nightmare on that side.
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Old 05-16-2018, 08:48 PM
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Originally Posted by chiaj144 View Post
Is that log in third gear? If not try it there. Just go WOT who cares if it's spinning it will give you better data than you're getting at 50% tps.
i would say its more likely in 1st or 2nd. But Ive done logs in 3rd gear but not a full swing. So say Im doing 40mph in 3rd and Im stalling around 2400-3k on the converter. If I mash it the tires will break loose and the tranny will more than likely downshift to 2nd or so. So how do I log in 3rd and take into account the 2400-3k stall?

Honestly in that log Im pretty sure I was spinning the tires big time. You know goosing it out of a local car show and making some boost noises. I think I just need drag radials to help plant the tires so I can goose it more and not have my *** end swing around as some dangerous speed and total the car.
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Old 05-16-2018, 08:55 PM
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Originally Posted by CyberGrey Z28 View Post
Might be traction? I had a bunch of inaccurate logs while spinning(low psi and rich spikes).

I ran my best trap through a standard 3 inch exhaust to corsa dual w/ bullet resonator welded in the I pipe. Didn't get a chance to open the cut out for a back to back test but I think it was making over 600rwhp.

Just noticed you weren't even WOT.
its definitely traction! Im pretty sure I was getting sideways if I remember in that log. Thought the 275/40r18 sumimoto htrz IIs would be decent but anything over 40% and boost causes them to spin.

So you were running a resonator in the ipipe and a full 3 Corsa catback? So a single bullet and then a corsa single in and dual out stock style muffler? We essentially have be same car and setup and your system spooked fine? You got any logs of boost and at what rpm? What tires you running?

Nope, Ive only been to full throttle in 3rd but at much higher speed like 100mph+ and at that point its like 5500-6k and full boost anyways. Most I can do from a low speed or stop is like 30% and I can creep up to 40-50-% if Im moving in 2nd or 3rd.
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Old 05-16-2018, 09:09 PM
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Originally Posted by LILHEMI View Post
3" crossover will kill spool. change it to 2.25" and prosper.
also FWIW the collectors on the headers are 3 and the entire pass side header is 3 into the vband to T4 adapter.


best pic I got to illustrate the design of there hotside. I actually had to modify it to fit the truck accessories but adding 3 to the crossover to clear the tensioner. But you can see the 3 pass side header collector that has the merge from the 3 crossover and then the 2.5 or 60mm WG port inline and continues 3 to the 3 CX SS cast T4 elbow. So even if by some miraculous miracle Im able to get a 2.25 or 2 crossover to fit it still merged into a 3 pass side collector/log into the turbo.
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Old 05-16-2018, 09:20 PM
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explain those valve covers
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Old 05-16-2018, 09:29 PM
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Originally Posted by LILHEMI View Post
explain those valve covers
stock valve covers. Stock coil brackets and coils. eBay aluminum fabbed coil covers, wrapped in 4D carbon fiber vinyl and a custom hoonigan decal I designed.
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Old 05-16-2018, 09:29 PM
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i like.
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Old 05-17-2018, 07:49 AM
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Originally Posted by customblackbird View Post

stock valve covers. Stock coil brackets and coils. eBay aluminum fabbed coil covers, wrapped in 4D carbon fiber vinyl and a custom hoonigan decal I designed.
That looks awesome and seems pretty straightforward. What brand vinyl and how is it holding up to the heat?
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Old 05-17-2018, 07:59 AM
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Wants to be fast and spool quick....but not loud....*shakes head*. The only other way to light it off quicker is in the tune. Whats the timing and commanded air/fuel?
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Old 05-17-2018, 08:28 AM
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I have 1.75" header tube into 3" collector to 3" turbo 90 to turbo then 4ft 3" to bullet muffler in a twin setup. Turbo starts to spool about 2800 and lights off hard around 3400. A single turbo setup should be even faster unless the turbo is really large. If the throttle is not fully open no matter how much air you have available it's not gonna make it IN the engine. From my experimenting, more air in creates more exhaust out which compounds the cycle until the exhaust causes a restriction or the waste gate opens. It all happens quick once it starts but very controllable with the throttle. Playing with small crossover tubing and back pressure balance to spool the turbo seams counter productive IMHO.
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Old 05-17-2018, 08:33 AM
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Originally Posted by Photochop View Post
That looks awesome and seems pretty straightforward. What brand vinyl and how is it holding up to the heat?
Ebay 4D. Coil covers don't get to hot. Prob in the low 100*F. Ive wrapped actual fabbed valve covers and never had an issue but that was with real 3M 3D carbon fiber vinyl. The decal is oracle outdoor and seems to be holding up fine. Its been like this for a few years now and is holding up great.
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Old 05-17-2018, 08:46 AM
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Originally Posted by ddnspider View Post
Wants to be fast and spool quick....but not loud....*shakes head*. The only other way to light it off quicker is in the tune. Whats the timing and commanded air/fuel?
haha I know, sounds crazy but the OEMs do it... so why can't I? All the new fords with the eco boost you can't even feel it come in, they are pretty quick and dont make a peep. Sure were talking like 2x the power but the concept is the same. small turbo, restrictive exhaust, quick spool thats all done by 6k is good with me

Ummm, commanded boost AFR is 11.7ish (happens in the 170kpa range, its leaner below to help with spooling, but I am also injecting 750cc/min of 50/50 water/meth starting progressively at 100kpa. Below is data from the log I pulled in the same area as above but includes timing and actual AFR + Commanded AFR. Idk why it was reading super rich at 1800-2k in the beginning, might have been light throttle/decel making the turn to get onto the main road before giving it throttle.

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Old 05-17-2018, 09:28 AM
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Your AFR is all over the place. You need to mat it from a slow roll and 0 tps to 100 to get a real idea of the spool.
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Old 05-17-2018, 10:00 AM
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Originally Posted by ddnspider View Post
Your AFR is all over the place. You need to mat it from a slow roll and 0 tps to 100 to get a real idea of the spool.
IT's in self tuning mode, I've made changes almost everytime I park it without letting or giving it time to learn. Doesnt look that bad with maybe 15min or learn time. Its in the 11.8 -12:0:1 in the higher boost range when its commanding 11.9:1. Its also fighting the sudden hit of 50/50 meth and adjusting fueling on that.
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Old 05-17-2018, 10:05 AM
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Originally Posted by customblackbird View Post
IT's in self tuning mode, I've made changes almost everytime I park it without letting or giving it time to learn. Doesnt look that bad with maybe 15min or learn time. Its in the 11.8 -12:0:1 in the higher boost range when its commanding 11.9:1. Its also fighting the sudden hit of 50/50 meth and adjusting fueling on that.
I wouldn't run 12:0 AFR even with meth on 93 octane, but thats just me.
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