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Some turbo install questions

 
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Scorpio  



Joined: 05 Jul 2007
Posts: 1957
Location: Brisbane, Australia

PostPosted: Fri Jun 06, 2008 9:34 pm    Post subject: Some turbo install questions Reply with quote

in the process of planning my bae turbo install on a NA keeping CIS, The BAE kit was andrews..
http://www.924board.org/viewtopic.php?t=21614


a few questions

1) what sort of boost can the stock injectors take b4 "popping" out

2) What are the CIS turbo users using to connect the "fuel metering plate section" to the turbo piping(i cant find big enough silicon hose) . How much boost pressure would the stock rubber boot take? Andrew seems to have been running it safely (pics)

3)The system uses two extra injectors which are boost activated. One injector sprays into the boot joining to the throttle body..
see pic ..
The other is the cold start valve.. Ive read that using the cold start valve as an extra injector isnt good as fuel will be sucked straight into the 4th cylinder.
I also think this would be detrimental to my"street car" as the cold start valve is diabled from its normal function. 'IF the CSV can be used' can it be electrically joined in parrallel so that it can be triggered both ways? im scared backcurrent could burn something in the extra injector comp or something controling the CSV.. Any suggestions








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MS1..EFI..
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ideola  



Joined: 01 Oct 2004
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PostPosted: Fri Jun 06, 2008 11:01 pm    Post subject: Reply with quote

Very cool stuff, Scorpio! As for the extra injector, there was a GTx variant posted over on Rennlist (there are links to it here somewhere, I'll go find later) that was running 1 bar of boost (IIRC). He was using a single extra injector that was plumbed into the back side of the intake manifold. I don't recall the BHP figures off the top of my head, but his car was a monster, and it had a top speed of 160+ MPH. My point is that I suspect that your single extra injector just before the throttle body is probably in a very good location, and is probably sufficient for a street car. If it were me, I would rewire the CSV for normal usage due to the concerns you mentioned (unbalanced fuel delivery across the intake runners, cold starting).

Out of curiosity, how is the fuel flow regulated, tuned and triggered for your extra injector?
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RC  



Joined: 25 Mar 2007
Posts: 2634
Location: Australia

PostPosted: Fri Jun 06, 2008 11:25 pm    Post subject: Reply with quote

Scorpio wrote:
Quote:
.. Any suggestions


Andrew NZ wrote:
Quote:
I have to admit that it would have been a lot easier to go for EFI, but it is nice to achieve reasonable power with the factory set up.


At least get yourself an O2 sensor so you know WTF is happening with your improvised fuel delivery system.

Roger
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Scorpio  



Joined: 05 Jul 2007
Posts: 1957
Location: Brisbane, Australia

PostPosted: Fri Jun 06, 2008 11:38 pm    Post subject: Reply with quote

forgot to mention those pics are on andrews setup ..

Im still in the planning phase

Quote:

Out of curiosity, how is the fuel flow regulated, tuned and triggered for your extra injector?






The sytem uses a powerlink extra injector controller, with the vacuum sensor coming out from the supplied(its a 931) throttle body.

Andrew had it dyno tuned to come on at the appropriate boost b4 the system leaned out. The powerlink injector conroller has two adjustable trim pots one is for boost at which extra injectors are activated and second is for the amount (pulse width) of fuel sprayed out of the injector.

I am still a fair way away from sticking the system in so dont exactly knw how fuel pressure will be regulated..as im guessing when boost is activated pressure through the CIS will drop slightly as extra injectors are activated, will it cause any significant problems?

Perhaps i could just use a much larger "single" injector at the throttle body rubber spray point? are their any prob with spraying fuel through the rubber boot, through the throttle body, through the intake manifold..perhaps the fuel rich air might interfere/clog vac lines ??
_________________
1979 NA
MS1..EFI..
GARRETT T25 TURBO
BILSTEIN SHOCKS
GT BASED CUSTOM BODYKIT

Brisbane , Australia
Think mean think fast
all youll see is
my Porsches Arse!!!
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Scorpio  



Joined: 05 Jul 2007
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Location: Brisbane, Australia

PostPosted: Fri Jun 06, 2008 11:45 pm    Post subject: Reply with quote

Quote:
At least get yourself an O2 sensor so you know WTF is happening with your improvised fuel delivery system.


An o2 sensor with A/F gauge is already on the shopping list

EFI would be nice, but atm i think its a little less costly to "refine" Andrews kit then to do a EFI conversion
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1979 NA
MS1..EFI..
GARRETT T25 TURBO
BILSTEIN SHOCKS
GT BASED CUSTOM BODYKIT

Brisbane , Australia
Think mean think fast
all youll see is
my Porsches Arse!!!
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RC  



Joined: 25 Mar 2007
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PostPosted: Sat Jun 07, 2008 12:27 am    Post subject: Reply with quote

Bonus then as it looks like you got Andrews controller too. Why not just use his intake tract with the CSV set up in it. Appears that he used the rubber boot successfully, although I suspect some blow through the AAV under boost. A 3" x 2.5" silicone reducing bend also fits the TB.

In the pic Andrew just tapped into the HP fuel line for the CSV. Sure they`re Y adaptors and not FPRs. Simple matter to install a stock EFI FPR or an adjustable one in series with extra injectors. Both will have input fitting for MAP and vary pressure accordingly. May or may not be desirable. Only a guess at best without O2 readings.

Standard mod is to increase CIS system pressure, giving greater differential against control pressure for enrichment across the board. The vac/boost WUR will also assist here. Not sure how Andrew blew his engine but with an O2 gauge you can monitor the fuel metering and throttle off if it leans out. An invaluable tuning tool for this type of experimenting. The CIS may be usable with conservative and intelligent tuning. Almost everyone has trouble trying to tune it on a modded or particularly boosted engine however. Personally I kick myself for not going EFI sooner but am fortunate that my valves and pistons survived.

Roger
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leadfoot  



Joined: 11 Dec 2002
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PostPosted: Sat Jun 07, 2008 1:14 pm    Post subject: Reply with quote

don't worry about an o2 sensor... better to get it tuned on a dyno and once it's set you won't be playing around with it...

Ebay is your source for silicon hosing, make sure you get the fiberglass reinforced silicon. As RC said 3.5 to 2.5" right angle reducer will fit.

Make a new pipe from the intercooler to the throttle and insert your injectors there.

Not sure what the turbo's do but for the AAV you might be able to tap into the the line between the metering plate and the turbo inlet. This would mean you don't see the pressure element but you are still counting for metered air. It might also be easier to bolt the AAV on the other side of the manifold for this.
Stu
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Andrew NZ  



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PostPosted: Sat Jun 07, 2008 6:33 pm    Post subject: Reply with quote

I only ran one CSV initially, and it was running out of fuel at higher revs under boost (on the dyno) so we added the other one to bring it right. There are lots of other ways to get around the fueling, but since we know that it was ok it's probably easier to start with the two to be on the safe side, and then you can play from there.

What about machining your manifold and mount the second CSV on the oposite side of the manifold to the original CSV. I was thinking about moving the second one there if I rebuilt the engine, as I wasn't sure how long the rubber boot would stand having fuel in it. You could use a silicon boot then and make better pipes from your intercooler.

I wouldn't worry about loosing the use of the CSV for cold starts. Mine never needed it even on very cold mornings, and Brisbane is a lot warmer than Auckland!!

RC, the engine dying had nothing to do with the turbo set up, as it ran the rod bearings.
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Scorpio  



Joined: 05 Jul 2007
Posts: 1957
Location: Brisbane, Australia

PostPosted: Sat Jun 07, 2008 9:27 pm    Post subject: Reply with quote

Quote:

What about machining your manifold and mount the second CSV on the oposite side of the manifold to the original CSV


would that mean uneven fuelling to cylinder 2 and 3?..
or is that a myth?

Perhaps tapping two injectors into the back of the inlet manifold..one in-between intake "1 and 2" the other between "3 and 4" ?
Andrew is the injector near the boot the same as the porsche Cold start injector ?
_________________
1979 NA
MS1..EFI..
GARRETT T25 TURBO
BILSTEIN SHOCKS
GT BASED CUSTOM BODYKIT

Brisbane , Australia
Think mean think fast
all youll see is
my Porsches Arse!!!
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ideola  



Joined: 01 Oct 2004
Posts: 15493
Location: Woodstock IL

PostPosted: Sat Jun 07, 2008 10:55 pm    Post subject: Reply with quote

On early GM cars, there was a style of injection called throttle body injection. This essentially positioned the injector(s) in front of the throttle body. For your setup, pre-throttle body would be ideal because it would minimize the concern of fuel distribution across the intake runners. So if you can come up with a hard pipe configuration before the TB, this would be your ideal location. The injector(s) can be controlled by a manual rising rate fuel pressure regulator, or electronically by a supplementary controller such as the one you already have, or ones from 034 Motorsport (and possibly other ECU manufacturers), or even a piggyback Megasquirt configuration (which could be a first step toward subsequent conversion to full-blown EFI).

I have seen an NA intake manifold modified in the manner suggested by Andrew (dual CSVs on opposite sides of the intake). My thought with respect to the CSV is that if it were really that inferior for distributing fuel across the runners, I'm sure Porsche would have identified it and come up with a better solution. Now, under boost, it may not be ideal, but I still think you would get adequate fueling across the runners, particularly if you were running one on each side of the manifold. I suspect the issue there is that the CSV simply can't flow enough fuel at high RPM/boost. A higher capacity injector would probably do better.

Here is a thread you should take a look at:
http://www.924board.org/viewtopic.php?p=211519#211519

Also, here is the link to the GTx variant and what he did for add'l fueling that I referred to earlier. In this case, Cliff installed a single injector on the back side of the manifold:
http://forums.rennlist.com/rennforums/showpost.php?p=4320253&postcount=47
(BTW, Cliff is a apparently from NZ).
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Andrew NZ  



Joined: 22 Jun 2004
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PostPosted: Sun Jun 08, 2008 8:17 am    Post subject: Reply with quote

Scorpio wrote:

would that mean uneven fuelling to cylinder 2 and 3?..
or is that a myth?


Possibly, I'm not sure.

Scorpio wrote:

Perhaps tapping two injectors into the back of the inlet manifold..one in-between intake "1 and 2" the other between "3 and 4" ?


That could work, or maybe even do what Dan and Leadfoot suggested and put them both before the throttle body, since you'll probably have to make a new pipe from your intercooler anyway. I'm sure you'd be able to shuffle the braided lines around so they'd both reach.

Scorpio wrote:

Andrew is the injector near the boot the same as the porsche Cold start injector ?


Yes.
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Scorpio  



Joined: 05 Jul 2007
Posts: 1957
Location: Brisbane, Australia

PostPosted: Sun Jun 08, 2008 10:07 am    Post subject: Reply with quote

Cheers, or can always make longer braided lines. Does anyone see any problems sending a stream of fuel through the throttle body?

Perhaps a stupid question
but what sort of fuel pressure increase can you run through the normal injectors?
the reason i ask is could the extra injectors actually be left out and something like the following unit used

http://www.msdignition.com/tc_24.htm

Could possibly be overkill, im guessing the cheaper equivalent is a boost controlled adjustable fuel pressure regulator..although that wont increase pump flow output just line pressure

increases fuel pump voltage thus increasing fuel pressure when boost is sensed...
can the fuel pump handle a little extra voltage? and would the resultant pressure increase through the injectors be enough?


Haynes extreme sport customizing says injectors can handle safely up to a 10% pressure increase

LEADFOOT
Quote:

Not sure what the turbo's do but for the AAV you might be able to tap into the the line between the metering plate and the turbo inlet. This would mean you don't see the pressure element but you are still counting for metered air. It might also be easier to bolt the AAV on the other side of the manifold for this.



ANDREW-- Do you remember at what boost PSI the extra injector controller starts firing at?

IDEOLA Thanks ideola just having a good read through that info..lots of good info there and some good ideas to start sorting through


RC Hey RC i think they are just Y connections, but i could always use a boost controlled regulator in series with the extra injector fuel lines (seems Andrew diudnt have a prob though with fuel pressure), would that cause the CIS to starve for fuel a little at boost or will the pump work harder to handle it?

Sorry for all the mini questions, just looking for thoughts from people that have a lot more experience then me
_________________
1979 NA
MS1..EFI..
GARRETT T25 TURBO
BILSTEIN SHOCKS
GT BASED CUSTOM BODYKIT

Brisbane , Australia
Think mean think fast
all youll see is
my Porsches Arse!!!
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Andrew NZ  



Joined: 22 Jun 2004
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PostPosted: Sun Jun 08, 2008 10:22 am    Post subject: Reply with quote

Scorpio wrote:



ANDREW-- Do you remember at what boost PSI the extra injector controller starts firing at?



I think it was about 3psi from memory.
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RC  



Joined: 25 Mar 2007
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PostPosted: Sun Jun 08, 2008 10:47 am    Post subject: Reply with quote

Scorpio wrote:

RC Hey RC i think they are just Y connections, but i could always use a boost controlled regulator in series with the extra injector fuel lines (seems Andrew diudnt have a prob though with fuel pressure), would that cause the CIS to starve for fuel a little at boost or will the pump work harder to handle it?

Sorry for all the mini questions, just looking for thoughts from people that have a lot more experience then me


The stock 984 pump is more than adequate. It will flow over 2L/min at up to 140 PSI. Also fitted to 930s, the turbo commodore and XR6 turbo boys use it as an upgrade since it will support 500Hp.

Should be little problem running an independent FPR (rising rate/boost controlled or not) to extra injectors in parallel with the CIS that is internally regulated to around 70PSI. A 10% or even 20% increase in system pressure should be OK for the metering unit and injectors.

There is NO WAY I would use or recommend that SMPS booster contraption from MSD. Other opinions may vary, everyone is entitled to theirs.

Roger
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