I/C=Slower?

[evildky]

ok so I went to the stip today with the intercooler for the first time since I added the I/C just a few days ago, here is the set up:

183k junkyard L28ET

MSD fuel pump and aeromotove rrfpr running 40 psi base pressure

palnet o-ring fuel rail with blue dsm 450 cc injectors

240 sx TB (this is a new addition as well)

megasquirt'n'spark running moby's maps

12x18x3 I/C

2.25 hot pipe

2.5 cold pipe

tail bov on the cold pipe between the I/C and the TB

 

I now have no bottom end!

best I can figure the piping is too large and the turbo is taking longer to spool

I chose this pipe as my end goal is 400 whp, should I go ahead with the upsized t3/to4e or should I reduse my piping or both?

 

on the upside with the new slicks I was able to get a 1.81 sec 60' (a personal best and the VLSD hates it)

I was running 13.010 while overheating with the stock managment and no I/C @ about 9 psi, I had it running great with no I/C on megasquirt @ 13psi and it sure felt a LOT faster, then I added the I/C and it all went to hell

which only got me a 13.4, a full 3 tenths slower than the old stock setup

[Guest traub83]

im no turbo expert but it sounds as tho your turbo is too small and is spinning as fast as it can to make boost.. I would go ahead with your plan and buy the larger turbo cause with a te/04e turbo a 2.5" pipe is just about right unless ya have miles and miles of it..

[Clifton]

I went from 2" with a small IC to 2.5-2.75 with a big IC. Once spooled and the tubing is pessurized, piping size will not make a noticable difference in terms of lag. When are you wanting boost by?

[evildky]

I was getting full boost by 3300-3400 rpm, now it's 4000rpm

[materchan]

if you're running a stock turbo, that cant be right, under load i can get full boost about 1000rpm lower than you. possibly tweak your VE tables, because now you are running colder and then more dense air possibaly? so you might be running leaner than before. i dont know this is just a shot in the dark

[thehelix112]

I've got 2.5" piping to and from and I get full boost just over 4000 too.

 

Why on earth did you make the hot pipe smaller than the cooler pipe? Should be the other way around I think.

 

Have you had it back on the dyno? Is the peak power the same do you think?

 

Dave

[Tony D]

I/C means different fuel and spark curves...

Start tweaking, the power will follow.

Piping size only matters as a function of volume being filled...and I/C adds volume, too. A compressor wheel that flows more will fill that volume faster, along with a proper dump valve (BOV) that will keep Turbo RPMS up allowing proper on-boost repressurization after a drop-throttle event.

You changed the air density and temperature, chances are you will need more fuel and can run more spark, also. This will help boost performance.

Boost Threshold should not be affected that much if fuel and spakr is correct.

[evildky]

I havn't dyno'd it yet but

I bent the wastegate actuator and turned the boost down till I got around 15 psi, after adding the I/C I upped the base fuel pressure to the afformentioned 40 psi, the log shows like 9:1 but thts just the stock O2 sensor and I just don't trust it, with the boost limited it seems to be backfiring and less and running stronger but still not where it should be,

 

as for the cold pipe being larger I figured it was one step closer to the TB which is 2.75" and I'd think that 2.75" all the way wouldn't do much good and would be harder to aquire and route

 

really considering the larger turbo, perhaps I will try more tuning for now but I need to get the big power numbers next spring

[Phyxius]

i have a t3/t04e with a huge ic and 3" piping....i get full boost about 2800 rpm.... it felt like my car was quicker with the bigger piping...

[Guest bastaad525]

maybe not the greatest reply here, but I have very little doubt that after adding my I/C, had I just left boost where it was (10psi at the time), that my car would actually have ended up slower. I too noticed that the turbo seemed to spool MUCH slower after the I/C, and I"m only running 2.25" pipe. Also my I/C isn't even that large, like 24" x 9" x 3", not as big as many guys on here run, so I'd figure much less time to pressurize it.

 

before my turbo hit full boost at like 2400 or 2600rpm, now it's more like 3000rpm. Does't sound like a big difference but when cruising on the highway at 3000rpm and then punching it I notice a HUGE difference in how long it takes to reach full boost.

 

Of course, with the I/C in I was able to up boost a bit, from 10psi to 13-14psi, and did end up with more peak power and torque, so the car is still faster, but the throttle response still sucks

[wigenOut-S30]

before I added the IC I was hitting boost at around 2600-2800 rpms. I ran a 13.8 @ 101 1/4 at 10psi of boost. I added a smaller NPRintercooler and 2.5" IC pipe. With that done and exact same boost I ran a 13.5@104. and then bumped it up to 11-12 and ran a 13.3 @106. I still get full boost around 27-2800 rpms. With the boost controller off the car and using stock wastegate I hit 7 ro so lbs of boost. The only difference I felt after adding my IC is that it was faster.

[sims76]

Full boost here at 3000RPM with my T03/T04E and spearco IC.

I also use 2.25" pipe turbo to IC and 2.5" pipe IC to TB.

[Guest bastaad525]

I need a better exhaust

 

I swear I have the laggiest T3 ever

[Hugh]

Tuning plays a bigger role in lag than you might think.

 

I would try leaning it out from 3000-4000rpm, because its probably gone rich there since the intercooler install.

 

Your intercooler will of course add some lag, but proper tuning can level it out a lot.

[Pyro]

The IC will have a pressure drop. So it is important to feed the wastegate pressure directly from the manifold (after the IC).

 

What IC are you using?

 

The hot pipe doesn't need to be that big. Just look at the 1 inch output hole from the turbo and you will see what I mean. 2" hot side pipe is enough for 400 hp. Turbos push a lot better than they pull so a big cool side pipe is more important. In your case a 2" or 2.25" or 2.5" hot pipe will not effect anything.

 

Your turbo is very slow spooling. My old stock T3 was at full boost by 2800 rpm. My new laggy hybrid turbo is at full boost by 3500. Maybe your wastegate is not closing very well or your turbo is sick or the engine tune is off.

 

I didn't notice any difference in spool time when I added my IC. Just a slightly fast car.

 

I use a 2.5" cold pipe and a 2" hot pipe with a spearco IC on my turbo and it runs great.

[evildky]

before I added the IC I was hitting boost at around 2600-2800 rpms. I ran a 13.8 @ 101 1/4 at 10psi of boost. I added a smaller NPRintercooler and 2.5" IC pipe. With that done and exact same boost I ran a 13.5@104. and then bumped it up to 11-12 and ran a 13.3 @106. I still get full boost around 27-2800 rpms. With the boost controller off the car and using stock wastegate I hit 7 ro so lbs of boost. The only difference I felt after adding my IC is that it was faster.

I ran a 13.010 with no intercooler! and now a 13.4 with, but its backfiring through first and second gear, gotta retune the maps

[mobythevan]

Since nobody asked, are you sure none of the piping, couplers, IC are leaking? With megasquirt you would run just fine with a huge leak in the IC piping, but when you try to build boost the turbo just wouldn't be able to get there depending on the leak size. Otherwise back to tuning like everyone else said I suppose. Sounds like maybe you were running lean before the IC install and now that IC helps get more O2 in the engine requiring more fuel your not keeping up. The way I see it is that MS should adjust for the extra fuel from the IC install. So I would think you have inadequate fuel supply (pump, injectors too small) or your just adjusted lean and you need to tune the VE tables. Since you have MSD pump, 450cc injectors, it should be that your VE table is lean and was before the IC install. Wideband??

[evildky]

Moby, it was rich before the I/C install I am running the dsm's wth your maps and it was rich but ran good and without the I/C, rough idle but power from top to bottom, and I did have it running like 28 psi base fuel pressure with my aeromotove rrfpr and msd pump, after adding the I/C I upped the fuel pressure to the 40 psi it should be at, and leaned out the bottom (idle range) and cold start maps, it's got the best idle and cold start it's ever had including the stock system! and of course triple check all the couplers and no problems there although I did blow one off when racing on sunday, I am strongly considering a vertical flow intercooler to shorten the piping and I really need to tune the maps better, we're about 600 ft above sea level here an I suspect my feul system flows a bit better than your did so i need to thin the maps to compensate for my extra fuel flow, and btw I really appreciate your sharing of info and maps without it I'd have been screwed