Jump to content
SAU Community

Recommended Posts

Hey guys i've got a R33 gts25t series 2 with the following setup:

Trust FMIC, Garret T3/t4(rated@350hp i think) t3 flange std mounting position, Trust Pod Filter, Custom Stainless steel Turbo dump/front pipe(liverpool exhaust), Catco Hiflow cat, Fujitsubo Super Legalis R catback. Apexi Powerfc, Apexi Avc-r set at @1.3bar(18.85pounds). Also Tomei Metal Headgasket so lower compression, Cp Forged Pistons Shot-peen rods, Sard 550cc injectors, Nismo Fuel Pump. engine rebuilt 12000kms ago.

Now i've got all the details out of the way this is the problem.

got it dyno tuned with Hitman a while back i'm VERY happy with his service and the tune TOP BLOKE, HONEST just like how others has described his skills and expertise and the results are;

[email protected] or 18.85pounds@ around 5000rpm (REDLINE on graph) AND

[email protected] or 14.5pounds. (BLUE line on graph)

post-9504-1130721617.jpg

i hit full boost nice and early around 2800-2900rpm on 1.3bar BUT the boost doesn't hold and by the time it approaches redline or even at 5800rpm boost HAS DROP TO 12pounds from 19pounds. and POWER drops too from 5000rpm onwards NO TOP END.

We did Mutiple runs hitman spent a good 1 1/2 hours after the final tune trying to keep the boost up but nothing work, tested the cat and its not the cat set the boost controll or full 100% solonied duty no good also.

Knocking level on POWERFC less then 20 on the Handcontroller so its pretty good.

HOW COME BOOST DROPS SO MUCH??? WHY IS THERE NO TOP END??? Is it the TURBO or maybe something else? any opinions??...

T3/T4 hybrid turbos are a real snake pit . Their original aim was to have a light weight (when compared to T04) T3 based turbine and hang a SMALL trim usually T04E compressor and cover on the cold side .

Back yard spares and Turbonetics take a look at them and decide that large trim compressors look much tougher and flog them off to the uninformed . Trouble is the poor little T3 turbine is going purple in the chops because the large trim compressor is trying to move the extra mass of air it can bite into .

The other problem is Wallys back yard turbos insists on boring out T3 or Skyline turbine housings for bigger turbines - the nozzle inside the housing gets machined away which you can't see and generally lag and or surge is the result .

The best T3/04E hybrids not surprisingly come from Garrett but for the money and real estate they take up the GTBB's do a better job .

Cheers A .

Not sure exactly on a/r sizes of the turbo, is it usually stamped/printed on the turbo itself? can i usually see it if i don't remove the turbo itself?

Its an original garret item that i got brand new about 2 years, i might consider a dyno run without the dump pipe connect and see if i get different results.

its 3" turbo dump front pipe to the cat, then the fujuitsubo super legalias R cat back tailpipe is 117mm, main pipe is 70-89.1mm. similar size to my previous exhaust apexi N1.

HOW COME BOOST DROPS SO MUCH??? WHY IS THERE NO TOP END???

what are you talking about dude??? The top end if the better looking part of that graph, even if it isnt totally smooth

The boost dropping off is only due to your turbo which is my guess as disco has already stated... they are a very random thing at times.

I'd be more worried why there is a dip around the 96-120km/h which looks more like a typical stock ECU dip.

Thanks for the inputs guy, this is a graph during the early stages of tuning.

its not even redline(7000rpm) yet but look at the power drop at top end.

post-9504-1130736587.jpg

i'm pretty sure a r33 gts25t isn't meant to do that in power especially if running at 18.85pounds of boost.(1.3bar)

:)

Turbo connects to the 3" dump/front pipe, can't use the standard dump pipe.

sorry guys i have read what discopotato posted but i don't really understand it. ''wally's backyard turbo?'' its a genuine garret item tho.

(i was always under the impression that a HKS2530 would of been a similar size to a t3/t04, rated around 350hp, and then you get the HKS2540 which is similar size to a T04) hahaha sorry if i'm a bit stupid.

but i'm posting at work. i really appreciate all the feedback guys

So reckon a NICE big turbo 3037's, GT30 will give me power around 270rwkw?

sorry guys i have read what discopotato posted but i don't really understand it. ''wally's backyard turbo?'' its a genuine garret item tho.

he means something that someone has made with no reall technical mind or perspective.

Just put a front and a rear wheel on and hoped for the best, obviously it has not worked.

If you want more power, do a search, all been covered before

well when ya have a look at it

ya have a worked engine, with a piss fart turbo hangin off the side

havin the turbo spoolin up and hitting full boost that early

looks to me the engine is goin way harder then what the turbo is producing. and cant keep up .

Your engine at the state you have it now, would be capable of makin 300rwkw ( from what i hear) and have a 350hp rated turbo on the side at 18psi.

Would you believe the exhaust would be so restrictive?

is it a stock exhaust ,

is it a 3 inch dump ?

do you have a different AFM?

let us know what the problem is, if i encounter it later on.

THanks

Barret

1. Not a stock exhaust (Fujitsubo Super Legalias R),

2. 3 inch Dump/front pipe right after the back of the turbo,

3. Standard R33 Gts25t AFM, (been told that there is no point of me changing it to a z32 since i only have 210rwkw) 225-230+ require Z32 correct me if i'm wrong.

FROM what others suggest its possible its just the turbos problem.

i've pin pointed it down to these possible causes

1. Turbo obviously too small

2. Dump/Front pipe (3" too big maybe, for this small turbo so it can't compress the air <same concept as having a 4" or 5" exhaust on a N/A lancer that would perform better with a 2 1/2">

3. AFM (i doubt it tho, at this power range 210rwkw i've been two by a few tuners that the std one should be able to handle it)

it wouldnt think it would be the 3 inch dump

i have a split dump 3" with a stock turbo , on 10 psi doin 187rwkw

obviously your tuner, has tuned ya power fc to all your mods.

Have you done compression tests?

with the AFM your not really far off 225rwkw, and if your goin to get a bigger turbo, you will have to consider it .

Pretty much all i can see is you have all the supportin mods just need a bigger turbo

Would think something like a gt30, or something in the gt3* range

or even a gt2835r

Also another thing i would consider later on is cams, if you havent already done that. make it a bit more reliable and safe.

drop the dump pipe off and let the turbo vent out and do a dyno run

see if you see the same problem. if so that rules out exhaust too small. if you make good power and the boost doesn't taper off then your exhaust system is too restrictive

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now


  • Similar Content

  • Latest Posts

    • And finally, the front lower mount. It was doubly weird. Firstly, the lower mount is held in with a bracket that has 3 bolts (it also acts as the steering lock stop), and then a nut on the shock lower mount itself. So, remove the 3x 14mm head bolts , then the 17mm nut that holds the shock in. From there, you can't actually remove the shock from the lower mount bolt (took me a while to work that out....) Sadly I don't have a pic of the other side, but the swaybar mounts to the same bolt that holds the shock in. You need to push that swaybar mount/bolt back so the shock can be pulled out past the lower control arm.  In this pic you can see the bolt partly pushed back, but it had to go further than that to release the shock. Once the shock is out, putting the new one in is "reverse of disassembly". Put the top of the shock through at least one hole and put a nut on loosely to hold it in place. Put the lower end in place and push the swaybar mount / shock bolt back in place, then loosely attach the other 2 top nuts. Bolt the bracket back in place with the 14mm head bolts and finally put the nut onto the lower bolt. Done....you have new suspension on your v37!
    • And now to the front.  No pics of the 3 nuts holding the front struts on, they are easy to spot. Undo 2 and leave the closest one on loosely. Underneath we have to deal with the wiring again, but this time its worse because the plug is behind the guard liner. You'll have to decide how much of the guard liner to remove, I undid the lower liner's top, inside and lower clips, but didn't pull it full off the guard. Same issue undoing the plug as at the rear, you need to firmly push the release clip from below while equally firmly gripping the plug body and pulling it out of  the socket. I used my fancy electrical disconnect pliers to get in there There is also one clip for the wiring, unlike at the rear I could not get behind it so just had to lever it up and out.....not in great condition to re-use in future.
    • Onto the rear lower shock mount. It's worth starting with a decent degrease to remove 10+ years of road grime, and perhaps also spray a penetrating oil on the shock lower nut. Don't forget to include the shock wiring and plug in the clean.... Deal with the wiring first; you need to release 2 clips where the wiring goes into the bracket (use long nose pliers behind the bracket to compress the clip so you can reuse it), and the rubber mount slides out, then release the plug.  I found it very hard to unplug, from underneath you can compress the tab with a screwdriver or similar, and gently but firmly pull the plug out of the socket (regular pliers may help but don't put too much pressure on the plastic. The lower mount is straightforward, 17mm nut and you can pull the shock out. As I wasn't putting a standard shock back in, I gave the car side wiring socket a generous gob of dialectric grease to keep crap out in the future. Putting the new shock in is straightforward, feed it into at least 1 of the bolt holes at the top and reach around to put a nut on it to hold it up. Then put on the other 2 top nuts loosely and put the shock onto the lower mounting bolt (you may need to lift the hub a little if the new shock is shorter). Tighten the lower nut and 3 upper nuts and you are done. In my case the BC Racing shocks came assembled for the fronts, but the rears needed to re-use the factory strut tops. For that you need spring compressors to take the pressure off the top nut (they are compressed enough when the spring can move between the top and bottom spring seats. Then a 17mm ring spanner to undo the nut while using an 8mm open spanner to stop the shaft turning (or, if you are really lucky you might get it off with a rattle gun).
    • You will now be able to lift the parcel shelf trim enough to get to the shock cover bolts; if you need to full remove the parcel shelf trim for some reason you also remove the escutcheons around the rear seat release and you will have to unplug the high stop light wiring from the boot. Next up is removal of the bracket; 6 nuts and a bolt Good news, you've finally got to the strut top! Remove the dust cover and the 3 shock mount nuts (perhaps leave 1 on lightly for now....) Same on the other side, but easier now you've done it all before
    • OK, so a bunch of trim needs to come off to get to the rear shock top mounts. Once the seat is out of the way, the plastic trim needs to come off. Remove 2 clips at the top then slide the trim towards the centre of the car to clear the lower clip Next you need to be able to lift the parcel shelf, which means you need to remove the mid dark trim around the door, and then the upper light trim above the parcel shelf. The mid trim has a clip in the middle to remove first, then lift the lowest trim off the top of the mid trim (unclips). At the top there is a hidden clip on the inner side to release first by pulling inwards, then the main clip releases by pulling the top towards the front of the car. The door seal comes off with the trim, just put them aside. The the lighter upper trim, this is easy to break to top clips so take it carefully. There is a hidden clip towards the bottom and another in the middle to release first by pulling inwards. Once they are out, there are 3 clips along the rear windscreen side of the panel that are hard to get under. This is what the rear of the panel looks like to assist:
×
×
  • Create New...