ok guys i have been searching and it seems there are many different options on what size of housing to run.

there are only a couple of people running a .70. They claim it works just fine and spool up is INSANE. The main concern seems to be EGT's and choking the exhaust on the top end.

loads of FD guys run .84 hot sides and love the spool up. they are even running this size with street ports and making over 400whp at 15psi. that sounds great.


my question is about stock ports. spooling a big turbo with stock ports is tough.
Fd ports are pretty big as it is so talking about stock 13brew ports is one thing.
Im talking about stock s4 tii ports.

would running a .70 cause problems to the motor at 15psi? Im talking high egts and combustion temps due to exhaust getting fed back into the intake stroke cause by the higher back pressure. not will it... i know egt's will be higher but will they be high enough to cause detonation. (15* timing at 15psi max on 93 octane pump gas)

any input from people that have experience with this would be great. thanks.

 

do you have a divided manifold? if not -i'm assuming you don't, then get a collected turbine housing. the sizes for tangential p-trim T4's (garrett, as far as i know) are .68, .81, .96 and a 1.x

so, get the .81
its a good match for stock exhaust ports. .68 is a bit too small and .96 is a bit too big.

 

i do have a divided mani

 

I had a Garrett T4 Ptrim 60-1 turbo with the .84 turbine housing. Spool up was pretty quick so you won't have much trouble spooling that. Honestly that .70 would be too small even on your S4, you'd also be minimizing your top end (just like you stated). Turbo Timmy on here has basically the same turbo as I did on my old car and I took a ride in that beast. Spool was quick around 3500 and top end was mighty nice compared to a stock TII turbo

 

Im running a master power t-70. 69mm inlet... Id kill for 3500rpm full boost. mine is more like ~5250rpms.

Having a huge intercooler dosent help spool but my intake temps are grrrreat.

alright so something in .8x A/r would be best then. .81 open or .84 divided. I have been watching ebay for ever for one. there is one on there now but the guy only takes money order and lives out of the country.

 

call precision turbo and have them ship you out a .84 tomorrow. $110 is what I payed if I remember right for my .81.

 

just got an email back from them.

"I do not make such a housing. I have .58, .68, .81, or .96 in P-trim and
undivided. These have a 3 5/8" V-band discharge. Price is $220.
__________
Don
PTE Northeast Territory 2 Sales Rep/Manager
hours 8 am to 7 pm CST M-F
phone 219-996-7832
fax 219-996-7749
email don@precisionturbo.net
website address www.precisionturbo.net"

 

I can probably get you a divided .84 P trim with v-band for around that price.

 

im running a 1.0 divided on my 60-1. it used to be an xs engineering t04e kit that has been upgraded with a 60-1 wheel/to4s housing. am i missing out? should i be running the smaller housing? man. . . i got mine ceramic coated and it would pretty well suck to get rid of it now. hehe. . . all in the name of performance, i guess. what do you guys think?

 

Your 60-1 with 1.00 A/R turbine will be fine. The smaller compressor will spool up faster then the larger compressors (ex: T70) even with the larger A/R housing.


~Mike.............

 

I swear Jacob, you're in love with pre-turbine backpressure...

 

i just want this turbo to spool up all at once. id like it to hit... right now its VERY linniar. like, it builds 3psi per 1k rpms. It doesnt come on all at once... and it pretty much loses boost when i shift.

I realllllly should have just picked a 60-1 60trim like every one else and been happy with it. Im willing to cut out on some top end power in trade for quick spool.
thats why i was asking about a .70 housing. I dont plan to do a high boost race gas map. If i ever got a port or did want to do a race gas, high boost pull then i would just put my 1.0 housing back on.


the right thing to do would be to sell this turbo and get a smaller one. Cant right now so rule that out. So i want to make it work as good as i can.

1. one step down to a .84 from my 1.0 will lower my power band down and help get rid of this liniar spool up?

The .70 should make for pretty much insta spool compaired to what i have now, The draw back is that power will fall off at like 6.5k.
A quick spooling 375whp at 14/15psi with a power band from 3k to 7k (falling off at 6.5) is what im shooting for.

 

i use to run a 1.0 a/r on my t04s on my stock port cosmo, boost was similar to how you described

i just today fired up and drove my car with a .84. even with a supid rich fuel map and my conservative ingition map, i got into boost a few times light thoral shifting near 4ish k

 

?

 

fixed.

 

Lol

 

before selling the turbo get a .84

You will have the responce you want.

 

corkey bell reccomended me a simliar setup 60-1 .81 or 84....said 81 will have a little more mid and .84 will be lose some of the mid take it to top...

 

i just remember fending off the herds of anklebiters in the rabbits den. don't forget, get that new exhaust first!!!! then the 50 shot

 

https://www.rx7club.com/showthread.p...=%22.70%22+t66

thats that guy running a .70 on a t66 with a stock port motor. that thread has dyno sheets and everything.

 

jared, i dunno now. i would get the .84... if that guy made only 370rwhp at almost 16psi then you will only get like 350 max at same boost most likely. damn s4's flow like ****. that .70 really is a choke, also his full boost comes on at like 4700rpms and to me that's not worth a 30rwhp loss. do the .84 so you will get full boost around 5300 or so and neil's exhaust. well, that's just my opinion kind sir


p.s. dont forget mang... COMP CHECK!

 

odds are im going to end up with a .84... but i wanted to explore my options before deciding.

i wouldnt assume im only going to make 350 at 16psi. thats selling this turbo short id say.

p.s. id gladly trade 30hp for 8psi at 3500rpm and full boost at 4500rpm.

 

Hey it made 379 Comp on that motor was in the 6s, timing was extremely conservative and, FWIW, that car trapped 122mph @ 16 psi. Honestly the difference between a .70 & .81/.84 is probably negligible. Comparing it to other dynos out there at the time, I could find no evidence that the .70 was choking it up top -especially running stock ports and relatively low boost.

 

im running a 67 p-trim divided .86, gets positive pressure at 3,200, full boose at around 3900. it is un tuned right now and the boost map has 15* of timing advance and pulls 10:1 afr's. hopefully i can get the spool time down on the dyno.

 

No offense, That dyno is certainly not something I would call responsive for that power level. And you can't compare different dynos it shows you nothing, especially with different cars.

-S-