For the guys out there interested in quicker spool up on their 16gs for autocrossing or stop light to stop light street driving, try swapping to a 6cm turbine housing. Its good for 400 rpm quicker spool. Did it on my small TD05H-16g with a 6cm port job and 10*clip on the turbine wheel. MUCH better bottom end response, the loss of top end I could not detect. The torque would hit you around 3000 rpm vs. 3400 rpm, could even lug it around 2600 rpm and actually get some power to come out of slow corners. The 7cm was laggy in comparison, NOTHING below 3200-3300 rpm. It basically shifts your entire torque curve down about 400 rpm, very nice for you autocross freaks. I could not detect any choking up past 120 mph. Actually one year Mitsubishi EVO actually ran with a 16g and a 6cm turbine housing.

Sounds crazy but David Buschur did it on his 91 Eagle Talon back in 91-93. He actually recommended it to me when I told him my 16g with the 7cm was laggy back in 1995. I had an automatic and needed the quicker spool for better launching. A nice ported 95 exhaust manifold port matched to a ported 6cm would be IDEAL for an autocrosser. That setup spooled FASTER than my T28 on my 2nd gen, WAY faster.

Quoted out of Turbo & High Tech Performance, September 1997 issue, pg73: "David hand-ported the exhaust manifold and 02-sensor housing while swapping out the 7cm2 turbine housing for a smaller, ported 6cm2 housing for better response....The following year, Dave got educated in a hurry. With an opened-up exhaust (2.5-inch diameter from the turbo back) that eliminated the cat, a larger fender-mounted intercooler, a Marc Hallman manual boost controller, an Extrude Hone-processed intake manifold and an HKS GCC that allowed more precise tuning of the fuel curve, Dave's best time in 1993 was a 12.34 @ 116.72 mph.

"...made history in doing so with an 11.98 second pass that eclipsed 116.36 mph. This was accomplished by installing the 7cm2 turbine housing, swapping on a tubular manifold, fitting an external wastegate and lightening the car 200 pounds."

So, it LOOKS like Dave went [email protected] mph on a 6cm housing, then went all out and swapped back in the 7cm2 housing to crack into the 11's.

The real nice thing about Mitsu turbo's is one V-band clamp, 4 exhaust manifold bolts, and 2 downpipe nuts drops the turbine housing/02 sensor out. For autocrossing it can be done in 20 minutes tops. Head out to a dragstrip and pop the 7cm backin. Total flexibility. Actually I have a spare 6cm housing on hand (bought used for $50, NO cracks) for when I swap to an EVOIII 16g, just in case.

Ahh just thinking of mechanical tunning makes me feel all warm and fuzzy inside ,then I get a splitting migrain because of all the possobilities wich can be used.

Being able to inter change between housings is a great idea but im not that dedicated. To be honest,, I would be interested in a mod that would work all the time regardless if im daily driving or autocrossing.

In regards to my cams I really dont think the regrinds are all that different from the original aftermarkets . What makes a cam a cam is it's specs of duration and lift.

I noticed that maybe my intercooler is too big for my setup and is most likley contributing to the lag im so desperatly trying to reduce,but im not in a position to swap to a smaller one.

So that leaves me with limited options. What else would you reccomend to fight laggyness?

I personally think that if I could get my hands on a 3 inch 02 housing with the evo 16-g bolt pattern then maybe that would help by releaving flow hence a faster spool.

Hmm lets elaborate.

Hmm,

Did a little adjustment on my car last night, tightened down my 17 psi adjustable wastegate rod a few turns. I had to dial back my HKS EVC but the point was to keep the wastegate absolutely pinned shut during spool up. I did a little datalog today and the turbo hits HARD at anything over 50% throttle. I was actually getting a touch of 4 wheel spin at the top of 3rd gear. There is a BIG difference running a stiff wastegate, even with the same maximum psi. Car feels MUCH more torquey and I don't look at the boost gauge as much anymore.

Revolution,
I also noticed my Big FMIC causes a touch more lag, 3400 rpm vs. 3200 rpm but its well worth it, I wouldn't compromise there either. I mentioned the cams because HKS 264 cams do not cause ANY lag increase IMHO. If you noticed lag increase than maybe something happened during the install or your not getting your valve timing right, just a thought.

The turbine housing worked for me, a very effective solution for the street. I was never tempted to put the 7cm back on but that was on a small 16g with a clip. I'm at the point now where I wouldn't give up the top end I have now for anything. Your fast running out of options though. I'd say your 3" 02 housing sounds like a good idea. I personally think a smaller diameter exhaust helps out on the very bottom end but thats me. Dennis Grant does run a full 3" exhaust with an open dump.

I don't know what the wastegate spring rating is on the EVOIII 16g is but if its only the 11 pound actuator than you might find some low to midrange torque by running a 17 psi or higher adjustable actuator. It really does change the way the turbo hits, it hits SO much harder and with less throttle even with the same max boost. Also, maybe your Magnus manifold is hurting your low end. It was never really designed for autocross in mind, more for power above 6500 rpm. The stock intake manifold has got to be ideal for autocrossing.

This doesn't make much since to me, but the other day I put a 7cm exhaust houseing on my 14b. I had it off changeing a few gaskits and figured what the hell. Well I have otherwise stock exhaust.

I noticed no diference in spool up but it does sound a bit diferent, and seems to actualy have more pull (just a bit) around the 3k area, but thats it.


But that doesn't seem to make since, oh well.

Your really not gonna notice a difference unless you have a 7 cm ported manifold. Might as well throw on your 6 cm housing unless you get (or got) your manifold ported. If you think about it, your not really doing anything when you upgrade to 7 cm if your manifold is only 6 cm.

Rick

okay, so let me get this right... with a small 16g & 6cm exhaust housing you spun a AWD on the top of third gear?????/ THATS AMAZING!!!!!!!!!!!!!!!!!!!!!!


secondly I have a 6 bolt bored .020 and 9:1 compression stock head cams etc...
front mount intercooler w/ 2.5" intercooler piping
2.5" turbo intake pipe through hacked 2g maf
my turbo is a ported 14b with a ported 7cm housing. I can build 12 psi by 2,200 rpms and 18 by 2,600 rpms?

you have horrible turbo lag.


p.s. -> 2g exhaust manifold is fully ported through the runners, opening between mani. and turbo is 2.5". the 7cm gasket was smaller than the hole so I had to make my own gasket. the o2 housing was also ported & 3" from the exit of the o2 to the rear of the car

You do understand that upped compression helps with spool time, don't you?

Wouldn't it make more since for me to get a 2G manifold? That would then help right?

I really don't understand how you can possibly be spinning the tires at the top of 3rd gear on a 16g unless you run the worst tires in the world. I don't care what housing you have, it is just not possible. I run 19 psi on the street and I spin a little in 1st and thats it, but I run SO3s.

Anyway, its a proven fact that you'll pick up top end with a 7cm housing. You may not notice it, but you definately do. Whether its worth the low end is personal opinion. All I know is that lag is overrated, boost is a downshift away.

ChicagoGSX said:

All I know is that lag is overrated, boost is a downshift away.

Click to expand...

AMEN!

Coup D E'Tat said:

You do understand that upped compression helps with spool time, don't you?

Click to expand...

yes, I also realize that I am running a
larger ported exhaust housing.
longer and bigger than stock intercooler piping (more area to fill)
and much larger intercooler (also more to fill)

ChicagoGSX said:

I really don't understand how you can possibly be spinning the tires at the top of 3rd gear on a 16g unless you run the worst tires in the world. I don't care what housing you have, it is just not possible. I run 19 psi on the street and I spin a little in 1st and thats it, but I run SO3s.

Anyway, its a proven fact that you'll pick up top end with a 7cm housing. You may not notice it, but you definately do. Whether its worth the low end is personal opinion. All I know is that lag is overrated, boost is a downshift away.

Click to expand...

Dsmtuners, take a chill pill. With a 10*F outside temperature on a 2g Eclipse GSX I spin 1st gear and 2nd gear with ease. The top of 3rd gear spin happened tonight for the 1st time, I must have hit a slick spot due to the cold weather cause I went opposite lock to catch it around 80 mph WOT, right where my HKS cams hit HARD.

I don't run a 16g on my 2G GSX, I was talking about my 91 Eclipse GS back in 95. I run a FPt28/28 on my 2G GSX which has a higher top end than a small 16g. Who the hell is talking about a 6cm housing having better topend than a 7cm? I never asked for your advice, I don't need it.

Hey pboglio I was contimplating the other day ,over the whole boost issue ,and well I was hitting boost at around 2800 but wasnt reaching my boost limit till 3100 -3200 rpm. The reason I asked you about my cams was maybe the stock cams would have been better for the mid rang,then my 264 regrinds.


I honestly thought that the exhaust manifold would have increased the spool dramatically ,but it only brought it down by about 400rpm. Even though I know my ssmim hurts my low end ,it works wonders for me on the top end factor wich helps alot while running down the 1320.

I keep asking myself about ways of increasing the speed of the air to the throttle. One such idea was to gradually expand the turbo i/c pipe from stock opening to 2.5 inches just b4 the i/c inlet thus minimizing the space the air would have to occupy. This might work but im afraid of trying it.


After I do this honing mod I will stop focusing my efforts on spool and power but more on how to put the power down,ie fatter rims and tires ,and better shafts and lsd's.

I heard obx was coming out with an lsd unit ,I just might check that out.

In regards to the wastegate ,,how would I go about getting my spring changed?

And lastly in you'r thoughts (totally off the topic here) does it make a difference if you run the boost controler from i/c /turbo outlet pipe nipple and wastegate or the blow off valve nipple?

I was asked this today by fellow dsmer but i could not come up with an answer , so i pass the question on to you.

Coup D E'Tat said:

You do understand that upped compression helps with spool time, don't you?

Click to expand...

I just started reading this post so I may be repeating this but higher compression to my understanding only helps off boost response and does not increase spool itself. mark

Seems that getting the boost signal from the comp housing or right after would help spool quicker. I woul like to try this with mne but it would require removing the turbo as the port is directly on the bottom as installed and I cannot get at it!
Pboglio would have an opinion backed by fact on whether smaller IC outlet pipes openingto a 2.5 before the TB would help. mark

sweet97 said:

I just started reading this post so I may be repeating this but higher compression to my understanding only helps off boost response and does not increase spool itself. mark

Click to expand...

From my understanding, it does help spool times, however, I can't seem to find a really straightforward answer (I did a quick search.)

However, I did come up with this -

Higher compression DOES NOT produce more exhaust gas. It DOES produce more exhaust pressure.... THIS is why it will spool a turbo faster.

Click to expand...

I get mixed answers in a bunch of threads, so if someone could shed some light on this, it'd be appreciated.

from my experience going from 8.5:1 to 9:1 did help turbo spool..

like I said my 14b with a ported 7cm exhaust housing will be at 10-12 psi by 2,200 rpms and full boost by 2,500 in fifth gear.. spinning in first and second commence about 3,500 @ 15 psi. sooner at higher boost

pboglio said:

Dsmtuners, take a chill pill. With a 10*F outside temperature on a 2g Eclipse GSX I spin 1st gear and 2nd gear with ease. The top of 3rd gear spin happened tonight for the 1st time, I must have hit a slick spot due to the cold weather cause I went opposite lock to catch it around 80 mph WOT, right where my HKS cams hit HARD.

I don't run a 16g on my 2G GSX, I was talking about my 91 Eclipse GS back in 95. I run a FPt28/28 on my 2G GSX which has a higher top end than a small 16g. Who the hell is talking about a 6cm housing having better topend than a 7cm? I never asked for your advice, I don't need it.

Click to expand...

This isn't VTEC. Chirping your tires on a hard shift doesn't constitute spinning. You didn't spin your tires, it was probably your clutch.

Revolution,

Your spool numbers are right on for your type of turbo. I've seen the datalog for another very well tuned EVOIII 16g turbo car and it hit 5psi @ 2600 rpm and 15 psi @3100 rpm in 3rd gear. Your spooling as fast as your average small 16g or T28, based on all of the datalogs I've seen, maybe even a little faster.

The exhaust side controls the engine rpm at which the turbo fully spools, I'd concentrate there. I run NO maf sensor (speed density), low pressure drop big I.C., Huge airfilter, 60 mm throttlebody,etc. None of this stuff on the intake side lowered my spool rpm, just helped reduce my intake pressure drop at high rpms. It did help in giving me quick spool up at PART throttle, but the rpm point always remains the same (15psi @ 3100 rpm, 20 psi @ 3300-3400 rpm). Your trying to gain spool up by reducing intake restrictions, but they aren't restrictions until WELL beyond the turbo full spool rpm (~3000 rpm). That strategy won't work.

You would have to increase the exhaust flow at low engine rpm (stroker or high compression), decrease the manifold runner diameter, or decrease the turbine housing A/R to alter the turbo/engine spool rpm point. The turbine side is controlling turbo spool speed. A big free flowing exhaust system would help too to a certain extent.

To increase the spring preload, add washers between the wastegate actuator and the compressor housing. I used a compressor, hooked it up to the wastegate actuator, and measured the pressure it took to just crack the wastegate valve open with the wastegate actuator bolted on. On my car I adjusted my wastegate from a cracking pressure of 16psi to 18psi. I already have a 17 psi wastegate actuator that has an adjustable rod. Your actuator I believe is a 11 psi actuator, so I'd add washers until I needed about 13-14 psi to just crack open the wastegate. This is all done with the boost controller pulled out of the loop with the car shut off. Now, this will keep your wastegate slammed shut under all conditions, especially during spool up. The wastegates tend to crack open a bit during spool up from the exhaust pressure, this helps out. Just adjust your boost controller lower to compensate and watch out for boost spiking. Probably cost you $2.00 in washers.

I source the boost controller off of a separate pressure fitting welded onto my lower I.C. pipe. I switched after seeing how my manual boost controller was bleeding pressure away from my CBV vaccum line, which was opening it during spoolup, causing turbolag at part throttle. This problem gets worse the stiffer the wastegate actuator you run, which is what I had. My T28 pressure source on the turbo actually reads LOWER than the intake manifold by a good 5 psi, I don't even use it. Cheers.

O.K.

I did a little DSMlink datalog on my turbo spool up. Looks like I'm hitting 5psi @ 2624 rpm, 15 psi @ 2964 rpm, and 20 psi @ 3100 rpm in 3rd gear, starting from 2000 rpm WOT. This is on a T28. Just 2 weeks ago I needed 3400 rpm to hit 20 psi. In that time I added Dejon Tools CBV stop leak pilot valve and added a lot of preload on my wastegate actuator. Looks like I'm hitting 196 ft/lbs of wheel torque @ 2624 rpm @ 5 psi, 233 ft/lbs wheel torque @ 2924 rpm @ 15 psi. My boost starts coming on at the same rpm as before, it just shoots up to its max faster now, I'm getting almost all of my boost by 2900 rpm now.

For reference, a T25 hits 5psi @ 2459 rpm and 15 psi @ 2719 rpm in 3rd gear. My T28 is now only 250 rpm slower in spool up than a stock T25. I'm not sure I could spool any faster short of running nitrous. I'm running a FPt28/28 turbo, HKS 264/264 cams, ADFX FMIC (23"x10"x2.75") w/2.5" short routed pipes, 60mm t-body, HKS VPC (no MAF), HKS EVC, 2.5" downpipe/testpipe, Greddy 2-3/8" catback, full turbo port work, RRE 2.25" turbo inlet pipe, DSMLink, 660 injectors, denso 150 lph fuel pump, etc.

Thanx for the heads up ,I guess im not spooling that slow after all ,but still worlds apart from the t25. I figure that if im spooling like this now then this extrude and hone job would help me just a touch more wich is always wanted.

Mind you my fidenza flywheel makes the car rev faster so maybe im not spooling so slow, but it could still be improved imho.

" on a 2g Eclipse GSX I spin 1st gear and 2nd gear with ease. The top of 3rd gear spin happened tonight for the 1st time "

All of that and only with a t-28? Umm what is the point of AWD then? Post a video with your AWD car SPINNING 1st 2nd and 3rd gear with a t28.

Holset ex40 ,simular size as t66 16psi at 3500rpm in 3rd

1993eclipseGS said:

" on a 2g Eclipse GSX I spin 1st gear and 2nd gear with ease. The top of 3rd gear spin happened tonight for the 1st time "

All of that and only with a t-28? Umm what is the point of AWD then? Post a video with your AWD car SPINNING 1st 2nd and 3rd gear with a t28.

Click to expand...

What do you mean "only with a T-28", thats the reason the wheels spin? I'm looking right now at a couple different torque curves for various larger turbos and its ugly. This is turning me off from ever buying a big turbo for the street. Its like a slow climb to power. The smaller turbo AND HKS cams just drops a torque bomb right on the tires and under certain conditions they just can't handle it. Flooring the throttle at 3000 rpm is pretty mild torque wise on my car, just as I would suspect. Flooring the throttle at 4000 rpm is a whole other universe, this is where the engine goes nuclear, the turbo dumping all of its boost near instantaneously.

I don't get it, you guys with AWD never spin your tires? You mean you AWD guys can't spin your tires in 2nd gear in cold weather? 2nd gear WOT in cold weather puts me sideways into the opposite lane. I'm getting to the point where I need to start worrying about 3rd gear instability. It happened just once, maybe a fluke, but my turbo has room for another 45 ft*lbs of torque. My DSMLINK shows 330 ft*lbs of wheel torque at 5200 rpm and 20 psi pump gas. If I crank it to 24 psi 100 octane and install my 3" catback I'm going to need to worry about 3rd gear instability around 5500 rpm if the roads are not absolutely bone dry.

ahhh ripping it in the cold ,gosh I miss that , the only thing im ripping are old newspapres to stick into the bon fires at the bus stops ,considering the past few days have all felt like minus 30 outside. And trust me waiting for these busses is no danm pleasure ,sometimes I cant feel my left prostate ,wich says alot about spanish guys and cold weather.


I am relieved to hear you say that im on the money for normally well tuned e16g turbos. Now after my exhaust housing gets back im going to jet coat everything from the mani and housing right down to the downpipe,in the hopes that could help.

In any case my gaol was to have the turbo see boost around 2500 and hit the limit at around 3000 rpm.

Now the next question on my mind is how im going to fit 17/9 advan's or volk rims on my 2g. And whether the new shocks should be soft and the springs harder?