bumpstart

NO ! retain the throttle delays on 6 p turbo engines, it means a lot to the bottom end,,
and delay plates or not makes 4/5 of fuckall difference to top end

IF you have the original s4 vacuum delay dash pot ,, or IF you have the s5 auto vac delay dash pot TB then there is a trick that will amount to keeping the secondaries and auxs shut until boost
this makes a very noticable difference for the better to tractable power at lower revs

rotorhead_izzy

iTrader: (36)

are you refering to the 5/6th ports when you say aux ports, because if you are i'm running a modded t2 lim, no 5/6th actuators

bumpstart

and so am i,, read what i posted,, keeping the delay throttles ,, and making them work only with boost
this will hold off the secondary and aux porting

ie,, the engine will run primary only till into boost ,, and the delays will blow open,, and show the larger ports to the inlet tract

this is a way of contolling you from having too much port at too low a rev ,, and having basically stalled airspeed,, which is terrible for fuel atomisation and TQ down low

the engine will have more area under the curve before boost
IE more usable TQ

removing the delays or going to stupid 80 mm single plane manifolds is going to cost you everything under 4000 rpm
and give FA improvement to the top end ( cause the manifold and mezzanine are the limiting factor anyhows )

rotorhead_izzy

iTrader: (36)

well thank you for the explanation on what you meant. now onto my question. how do you make the delays work only with boost?

bumpstart

the original s4 turbo TB can occasionally be found with a direct action vac delay setup
if you have one of these,throw away any one way valve and feed the delay can with vac taken from the primary runners only
when the port becomes inefficient boost will build in the runner and push open the delay can directly ,and control the ouput angle of the delay commisurate with the boost

-- with the s4 unit you may have to use a tee and bleed to tenuate the signal a little,, this is to prevent a surge as you come off throttle in higher gears
( if too strong a signal , can amount to acting like a cruise control in 4 and 5th gear and continue momentarilly when you lift up throttle or till you knock the car out of gear )

if you have the s5 auto unit,, it also uses a vac delay throttle
,, this one is not direct acting on the delay TB
and so you just hook it to primary runner vacuum without one way valve
when the port becomes restrictive,, the can will realease ,, and the delay throttle will this time follow the output angle of the main throttle

as such this TB will have no " cruise control " effect in higher gears
though its improvement low down is not as marked as with the s4 delay setup

rotorhead_izzy

iTrader: (36)

Well thanks for the info. I will try and source another t2 tb.

bumpstart

your looking for the delay can pot ,, not all TBs have them,, later s4 and s5 manuals are fully mechanical drag delays
auto s5 is the easiest one to get ,, the early s4 turbo one may be tricky to find in the US
( cause you got the year delay )

be aware when swapping s4 and s5 TBs there is a minor difference in the height of one stud that you may have to correct by swapping studs,, or fixing with a washer stack

rotorhead_izzy

iTrader: (36)

Well I need a s5 t2 tb because mine is damaged. Then I need to source the delay can pot. Would an s4 n/a tb have it?

bumpstart

its not quite the same , look for the s5 auto TB
pic-


Uploaded with ImageShack.us

the s4 t unit instead is a bigger alum looking triangle

rotorhead_izzy

iTrader: (36)

Update:

I have updated this in a while. The car is still running strong, very reliable. I was finally able to run the dyno with the car. I ended up with 322 whp and 259 ftlbs. Very conservative tune still. Here's the link to one of my runs:
https://www.youtube.com/watch?v=BhAI...e_gdata_player

RxManny

Do you have any pics of your engine bay how it looks...
How hard was it to boost the n/a for yah? Im doing an n/a s4 turbo for a friend...

rotorhead_izzy

iTrader: (36)

I'll post some pics later tonight. It wasn't all that bad depending on what parts you're planning on using.

On a side note. Got my car tuned by Steve Kan. On 2lbs less of boost I made 340 who and 275 ft lbs.

RxManny

Nice thats some decent power for that setup..

rotorhead_izzy

iTrader: (36)

Thanks. Sorry I haven't posted pics of the current setup. Currently doing a 6 port turbo 1st gen at the moment and its taking up a lot of my time.

~Rev Free~

Old thread bump, but I'm currently looking into going the same route, thought this could use some more exposure.

rotorhead_izzy

iTrader: (36)

What questions do you have? I currently just did a 6 port turbo GSL-SE

~Rev Free~

Well, I'm planning on building for Time Attack and in the class I'm shooting for, (Enthusiast) it stipulates that the "OEM ECU must be used. The OEM ECU may be reprogrammed and/or a "piggyback" ECU may be added."

I guess this isn't necessarily the right place to be asking about ECU questions, but if you have any comments on what route would be best, I'd appreciate the feedback. So far, I can see my options as being SAFC and Rtek, I don't know what else is out there that would work within these rules.

I'm only looking for about 240-260 hp at the wheels, so I'll be staying with the stock turbo for now and hoping I can transplant most of the parts from my blown S4 13BT. The engine currently in the car (S5) is a bone stock re-manufacturer with approx. 40k on the block.

Just a side note; since I'm in CA, I'm stuck with 91 octane and also for the class, I cannot use alcohol or water injection.

rotorhead_izzy

iTrader: (36)

Well due to your classing restrictions, I'd say an rtek is your best bet. Try to get something that you can tune like a 2.X. You're going to need to be able to tune your timing map to compensate for the higher compression and higher compression chamber temps.

As far as turbos go.... You're going to need to have something with some efficiency. Stock t2 turbos are not very efficient so they dont really make for a reliability in a 6 port build. I'd recommend at least a stage 1 Bnr, and an upgraded top mount or fmic.

My Bnr stage 2 makes a reliable 340 whp on 12 psi. Soon I'm going to run water meth.

~Rev Free~

Rtek seems like the only option I have available to me.

My next question is about intake manifold(s). I have a blown S4 13BT in my garage all dressed and I was wondering if I should just strip that blocks LIM and UIM to use those on my S5 engine or hold out and try to find S5 "turbo" LIM and UIM?

I've spent a few hours searching now and have read that the S4 and S5 LIM and UIM's are different (internal dimensions), but not by much?

Also, since my S4 "turbo" block is still complete, that means I've got the factory turbo there to use, but from everything I've read, I've gathered the idea that it's pretty much a waste of time to use that turbo? Is there anything I can actually do to it or with it?

rotorhead_izzy

iTrader: (36)

Yes there is a difference in manifolds, but since you aren't going for huge power numbers, I'd just use the s4 t2 manifolds.

As far as the turbo goes, you can use the stock t2 turbo as a core and send it out to Bryan at bnrsupercars and have him work it over for you and make a hybrid turbo. That's what I did. Bnr stage 2.

~Rev Free~

I've tried to find out what the exact differences are through searching, but came up short. Do you have a link where I could read more about these differences?

I came across this regarding the UIM:
FC3S Pro v2.0:* FAQ - Zenki versus Kouki Upper Intake Manifolds

I'm just wondering because I'm hoping I can also build for future growth with this setup.

In regards to the S4 turbocharger, I was at first under the impression that because it is inferior to the S5, it could not be modified to overcome its inherent shortcomings, so it was best to just start with a S5 core, but I take it I was mistaken?

I've read about the differences here:
FC3S Pro v2.0:&nbsp FAQ - Zenki Versus Kouki 13BT
And the BNR "wastegate fix" (sorry it doesn't seem to let me link directly):
bnrsupercars.com

rotorhead_izzy

iTrader: (36)

I don't have a link on the intakes. Like you posted above the runner lengths are different and I believe the s5's are just a bit wider too. Don't quote me on that one.

Stock for stock, s5 turbos are by far better due to the wastegate design. But when modified the stack up well. Bryan at Bnr says that he can make the s4 better than the s5.

What's your end goal for power?

~Rev Free~

No problem, it's of no importance, just something I've been curious about.

I've read quite extensively about the wastegate design, but I didn't know that he could get the S4 to stack up and exceed the S5 (is there a thread or something where this is stated?). Good to know, so that means I can just keep my S4 turbo and related components. Cost savings help anywhere and everywhere, lol.

Honestly, I'd be quite happy with 240-260 to the wheels. The engine is currently stock with a bad exhaust leak, it's fun and all, but the lack of power leaves me completely uncompetitive.

rotorhead_izzy

iTrader: (36)

I think he has it listed on his website. If you are looking for 240-260, get a Bnr stage 1 and run stock boost... 8 lbs.

I know how you feel about being uncompetitive. I use to run in sts... It was terrible. Now its a blast

RotaryEvolution

iTrader: (30)

i have no experience with the 9.7:1 turbo 6 ports but the 9.4:1 6 port engines wanted timing and lean mixtures to provide any real numbers, they just ran like total garbage below 15* advance in boost and sub 11.5:1 AFRs(running smooth but like they were semi castrated). by being overly conservative to start with i quickly moved in the other direction to see real gains.

so technically my response is that they suck unless you tune them aggressively. lower compression turbo 4 port engines ran merrily with little power loss with less timing. turboing the engine is still a major step up but when dynoing a car and losing 50whp due to those minor expectations of the engine is quite noticeable to me. i however did stop at 18-20* @13psi with a 12*split, this is really only 13-15* of advance after the 5ATDC mark correction but still semi aggressive for the higher compression.

personally i also wouldn't push more than 13psi on that compression ratio, even that is a high figure.


if you're running the TMIC and run into severe boost drop off past 6k RPMs then have a hard look at your intercooler and find a spot to bury it in your yard. even with a 15psi wastegate spring and the line disconnected the engine was constipated beyond belief without an intercooler upgrade, dropping to 7-8psi sharply after that point even with the wastegate completely off(basically wired shut).