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Vapor Transmission
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I'm thinking of upgrading my Injectors, but i just need some views and opinion before i do it. Now i have APH motor:-
APH - New Beetle 1.8t engine
1.Exhaust System: VW put 2L exhaust on the NB 1.8T!
2.Small Injectors, and 3 bar Fuel Pressure Regulator (sufficient for 150HP that’s it; maybe 160 max.)
CR of 9.5:1

The 1.8T NB (APH code) has a "baby" K03 turbo--not same as Golf and TT 1.Exhaust System: VW put 2L exhaust on the NB 1.8T!
2.Smaller Intercooler (even smaller than Golf part). Less air through turbo = less boost.
3.Small Injectors, and 3 bar Fuel Pressure Regulator (sufficient for 150HP that’s it; maybe 160 max.)

Now i have KO4, GIAC KO4 Program, and 4bar FPR. Now as you all read APH has the smallest injectors "APH, 281.78cc/[email protected]" Now i'm thinking of going with the 03 GTI Injectors which are i belive 369cc/[email protected] (correct me if i'm worng).

Now should i Upgrade, will i gain HP. Would i have to change my Fuel Pump? Or should i go with the AWD 317.46cc/[email protected] Injectors?

LMK and Thanks
 

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I believe the 225HP TT's also use 317cc injectors.

I saw a table somewhere recently of models and what injectors they used, but searching for a second, I didn't find it. :(

What kind of boost are you really running w/the K04?

With the 369cc injectors, I'd imagine you'll have to crank it back a long way to make the computer think it's putting out the right amount, but it'd be nice to just have short bursts.

I'm sure there's an equation to tell ya, but I wouldn't know it. ;)

Sooo...

How 'bout an Adjustable fuel pressure regulator and those phatty injectors? :) All that combined w/limiwinks should give you enough control to get it straight, right?

I bet you could even step it back down to the 3bar range of pressure if you're got that much flow in the injectors.
 

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Like i replied in your vortex post, if you're still using a stock sized MAF than you don't need any bigger than 317cc injectors... you can try 3 bar, 4bar, or an adjustable regulator to fine tune from there. The TT uses injectors that are rated at 360 or so cc at 4 bar of fuel pressure, which is equivalent to 317cc at 3 bar. No power to be had from bigger injectors unless your current fuel system is maxxed out, which you would need a wideband or VagCom to tell.
 

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Hehehe. For Zookie, I'd say keep that 4bar FPR, and get an adjustable FPR. :)

I know that car's still growing. ;)

Hmm. I've heard of rising rate FPR's, I don't THINK all adjustable FPR's are, I dunno; deffinately something to educate myself on. You might want to check that out.
 

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pretty much all fpr's are rising rate to some extent. Ours are 1:1 meaning that the fuel pressure goes up 1psi for every 1 psi of boost. An FMU, or fuel management unit (definitely an overly technical name for a relatively primitive tuning strategy) either uses different disks for different ratios or the cartech and beigi fmu's are infinitely variable within their minimum and maximum range.
 

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The Flying Englishman
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Chips are written for a specific combo of FPR and injector size. If you change one of them you'll either run rich or lean. Contact GIAC and ask what combo of FPR and injector they recommend for that specific program. Just swapping out the injectors isn't going to give you any more power.
 

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Oh yeah, I deffinately agree w/Pittbug. No injector change is really gonna provide you any benefit by itself. But if you're using a manual boost controller in addition to your chip, or if you plan on having a new chip mapped out to fit your modifications, I think they'd be a good idea. Deffinately needs to be tuned to fit YOUR application though.
 

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Pittbug said:
Chips are written for a specific combo of FPR and injector size. If you change one of them you'll either run rich or lean. Contact GIAC and ask what combo of FPR and injector they recommend for that specific program. Just swapping out the injectors isn't going to give you any more power.

You're correct, to a point. But our ecu's are known for being VERY adaptable, and will adapt out the extra fuel to a point. You don't want it to be adapting any more than +/- 10% on block 032 in the vagcom, but the other thing is that you can adjust your trims with lemmiwinks so that you can run bigger injectors. You can also use a bigger maf housing with significantly larger injectors, since the bigger housing makes the ecu think that less air is coming in it will fire the injectors less and O2 sensor correction will make up the difference.

Not that you want or need to do this, but I tried running 440cc injectors (green tops) on my car and then putting my 3 bar fpr back in.... it sputtered the first few seconds but then adapted and held an idle. Drove pretty well, but once i got under boost it would run so rich that I had 3 foot flames shooting out of my exhaust cutout. I'm betting that if i could have backed the pressure down to 30 psi or so, that it might have been ok, but i didn't have VagCom at the time so who knows.
 

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Keep It Real
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Scarab_Beetle is absolutely correct in what he said in his reply, anything larger than 317cc injectors with the stock MAF is a waste.

You don't want to use GTI injectors, if you want to do this right you will want to use the Audi TT 225hp injectors that physically match your stock long nose injectors.

The first thing that you want to consider is does your engine currently have enough air flow capability to deal with the larger injectors you plan to use (no) and the second consideration is whether or not software for the setup you indicate is available (yes), check with Neuspeed and GIAC.

The Audi TT 225hp injectors are 386cc, adding this injector to a New Beetle with a K04 turbo and software would be a complete waste of time and money, it may trigger DTC's, a CEL and even cause drivability issues.

Although the scan tool suggests that the ECU is only capable of a 10% plus or minus adjustments here, the newer VW/Audi ECU's will account for a 25% plus or minus correction. Just like with turbo boost the same goes for fuel, pressure is not volume and volume is what you would want to be concerned with.

The whole idea of an adjustable FPR on these cars is to set the FP so that the ECU has to make only minimal idle and run adapt corrections, the ECU will adjust to variances with in it's parameters no matter what you do and anything beyond this will result in DTC's, maybe a CEL and possibly other issues.

With your present setup and the addition of these large injectors, you will need to use an Audi TT 225hp 3" MAF housing, a front mount intercooler, a good intake and exhaust system and the correct software to start.

With this kind of upgrade on this car, you will likely only need the factory 3bar FPR but that will depend on the software.

Although A/F is high on the list, there are many ECU parameters that must be tuned and balanced when making changes such as these, it can be extremely time consuming and very difficult to know if you are headed safely in the right direction even with the use of Lemmiwinks etc.
 

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The Flying Englishman
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So what it boils down to is if you swap out your injectors, you need extra twiddly bits, gizmos and stuff to make them work, especially since GTi injectors are more than 10% over your current set.... So back to my original statement: "Just swapping out the injectors isn't going to give you any more power."


edit: can't have twiddly bits and stuff without gizmos :D
 

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No doubt, otherwise how are you gonna monitor the twiddly bits and stuff?

Approach with caution and move forward, I think it's good idea. But w/more stuff you add more things that can go wrong. The twiddly bits will help keep everything right & proper w/the stuff; but you really need the gizmos to keep monitor of all the stuff & twiddly bits.

I couldn't agree w/pittbug more. And I think it's somethin' you should do. :) (reliability WILL take a slight hit as you get things worked out; so you might wanna just get the parts and wait for warmer weather)
 

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Too Cold NB1.8T said:


The Audi TT 225hp injectors are 386cc, adding this injector to a New Beetle with a K04 turbo and software would be a complete waste of time and money, it may trigger DTC's, a CEL and even cause drivability issues.

Don't forget Too Cold, those 225 injectors are 386cc at 4bar... if you run the calculations you'll find its roughly the same as the 317's at 3 bar, maybe a teeny bit higher, but still about the same.
 

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Scarab_Beetle said:
Don't forget Too Cold, those 225 injectors are 386cc at 4bar... if you run the calculations you'll find its roughly the same as the 317's at 3 bar, maybe a teeny bit higher, but still about the same.

The static rating of the injectors is not related to the FPR, it is referring to the flow capacity of the unit. The ECU will ultimately control the regulation of fuel flow regardless of injector rating.

The question is whether or not adding only larger injectors to Zookie's K04'd APH engine will yield any benefits and the answer is, no.
 

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I don't think Zookie mentioned ONLY adding larger injectors.
Now should i Upgrade, will i gain HP. Would i have to change my Fuel Pump? Or should i go with the AWD 317.46cc/[email protected] Injectors?
_Yes upgrade. :) But not the injectors alone.
_No you won't gain HP, but you MAY be able to run more boost without running out of fuel, so you MAY be able to up the boost which WILL add to your HP.
_No you wouldn't have to change your fuel pump.
_You'd probably be fine going with the 317cc injectors; but should be able to tune it (with the proper modifications) to use either 317cc or the 369cc injectors.
 

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Keep It Real
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Zookie said that he was thinking of adding GTI 369cc injectors to his system which consists most importantly of a K04 turbo, this is what my responses were based on.

The much smaller 317cc injectors wouldn't require any of the changes that I previously mentioned but also wouldn't be worth the time and expense to change as the improvement if any, would be minimal.
 

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my turbo is bigger!!!!!!!
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i got some 1000cc.... might run a tad bit rich tho :D
 

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Too Cold NB1.8T said:
The static rating of the injectors is not related to the FPR, it is referring to the flow capacity of the unit. The ECU will ultimately control the regulation of fuel flow regardless of injector rating.

The question is whether or not adding only larger injectors to Zookie's K04'd APH engine will yield any benefits and the answer is, no.

Not to start an argument, but the flow rating of an injector has to have a corresponding pressure rating. Thats why the manufacturer rates the injector flow at a given fuel pressure. No pressure, no flow. And clearly they would have less maximum flow at 2 bar than they would at 4 or 5.

The reason I brought it up is because the TT injectors can be pricey and they won't flow any better than the GTI injectors at the same pressure. It is starting to get off on a tangent but its still relevant information.
 

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Scarab_Beetle said:
Not to start an argument, but the flow rating of an injector has to have a corresponding pressure rating. Thats why the manufacturer rates the injector flow at a given fuel pressure. No pressure, no flow. And clearly they would have less maximum flow at 2 bar than they would at 4 or 5.
This is true to an extent because a fuel injector manufacturer will chooce a pressure for a given sized injector in order to be able to list a flow rating at the injectors most efficient flow level which is usually a maximum of a .80% duty cycle, however in a real world application on these cars the ECU will over-ride everything and choose levels within it's preset parameters regardless of what FPR you decide to install.

The reason I brought it up is because the TT injectors can be pricey and they won't flow any better than the GTI injectors at the same pressure. It is starting to get off on a tangent but its still relevant information.

1. Anyone who is putting price as their first or main concern, should not be entertaining thoughts of persuing this kind of upgrade.

2. There are reasons why every tuner that I have spoken with who is involved with this type of upgrade for the 1.8t, specifically recommends the Audi TT 225hp fuel injectors and not those from a Jetta etc., this includes Neuspeed and GIAC.

3. The stock Audi TT 225hp 1.8t uses a 3bar FPR, not a 4bar.

4. Both Neuspeed and GIAC K04 and E05 turbo/large injector software specifically uses "Audi TT 225hp" 386cc injectors, an "Audi TT 225hp "3" MAF housing and a 3bar FPR.

The pressure that the injector manufacturer uses to reference the flow of a given injector is not necessarily the pressure that will be applied to a particular real world engine setup, these are only specs and characteristics to be considered and used as guidelines by a would be engine builder/tuner etc.

There are many other things that assist in determining injector type and size and FP requirements etc. when setting up a properly performing engine, unfortunately, it's rare that these requirements are linear based.
 
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