Going from a TXS st1 w/TDO4 to VF29 do I need to change the map for now?

[Camperguy]

Hey I`m running a TXS st1(unichip/plug&play) with samco`s,Borla header & up-pipe.I had a custom map programed on the dyno for my car.I am still running the 2 factory cats (down-pipe+mid) .I`m am going to be adding a VF29 and keeping everything else the same can I use this map safely untill I can scrounge up enough cash for injectors,fuel pump,down-pipe and a stage 4 flash and dyno tune.

Thanks Bill

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[Davenow]

if you run stock boost control levels or slightly above you will be fine.
Get the downpipe before the turbo. You will see more HP gains with the downpipe and stock turbo that you will with a larger turbo and stock exh

[Camperguy]

Thanks Davenow
I am running the TXS boost settings which is...
12psi 1st
14psi 2nd
14.5psi 3rd
15psi 4th
16psi 5th
of coarse the stuff is tapering down in the upper bands at high rpm.

I was just gonna toss on the VF29 till I can save up for the STI injectors,Walbro pump and Bosal down-pipe.I was leary on putting the DP and VF on together as I thought it would lean me out to much before I got the fuel system up-grades.I was thinking of going with a Cobb AccessECU upgrade instead of going with my TXS unichip and a stage 4 program.I gotta call Cobb and see if they have a close map to my mods.


Bill

[Concillian]

I think you're going to find yourself running out of fuel without changing the boost map.

The stock turbo tapers down to 12-13psi at redline, and that turbo probably isn't going to taper as much. Even with the stock turbo, IDCs are getting up there. Keep the boost down on the vf29 and you'll be okay.

I think it's not so much the peak boost that you need to be concerned about. It's the boost in the 5000+ RPM range. You don't want to be exceeding the stock boost curve in that range by much at all. That's where you would be in danger of running lean.

As an example, with just an uppipe and IC hoses, I was seeing over 90% IDC between 5250 and redline (93% peak around 5500, coinciding with the HP peak.) If you have 93 octane, you probably have a little more room there, as you're probably leaner. This was on a Vishnu custom dyno tuned Unichip on 91 octane, before I started using the UTEC (I was using the UTEC to log IDCs though).

It depends on what boost curve you get. If the curve tapers severely, then you can safely run more peak boost than if it's relatively flat.

[jblaine]

I think you're going to find yourself running out of fuel without changing the boost map.

Agreed, and even moreso when October onward hits... Bad idea.

Get the downpipe before the turbo.

Agreed.

[Camperguy]

Originally posted by Concillian
I think you're going to find yourself running out of fuel without changing the boost map.

The stock turbo tapers down to 12-13psi at redline, and that turbo probably isn't going to taper as much. Even with the stock turbo, IDCs are getting up there. Keep the boost down on the vf29 and you'll be okay.

I think it's not so much the peak boost that you need to be concerned about. It's the boost in the 5000+ RPM range. You don't want to be exceeding the stock boost curve in that range by much at all. That's where you would be in danger of running lean.

As an example, with just an uppipe and IC hoses, I was seeing over 90% IDC between 5250 and redline (93% peak around 5500, coinciding with the HP peak.) If you have 93 octane, you probably have a little more room there, as you're probably leaner. This was on a Vishnu custom dyno tuned Unichip on 91 octane, before I started using the UTEC (I was using the UTEC to log IDCs though).

It depends on what boost curve you get. If the curve tapers severely, then you can safely run more peak boost than if it's relatively flat.

Well I run 94 octane fuel but doesnt the TXS plug+play harness have its own boost solinoid driver?and wouldnt that driver still follow the same preset boost curve regaurdless of the turbos ability to flow more air at higher RPM`s? I`m new at this stuff so dont beat me up to bad I just thought 16psi was 16psi I thought the chip would cut boost down to keep it at its set parimeters and the fuel requirements would stay the same.Now when I talked to the guys at TXS they said dont even add a down-pipe without adding injectors+fuel pump then change the mapping The guy I bought this turbo off of was running "No fuel management at all"and was running full catless exhaust with dumps and MBC@16psi for over 15,000 miles ....Well regaurdless I`ll probably wait till I get all my pieces together and send out my ECU for a Cobb reflash while I install the stuff.

Thanks Bill

[AWMIII]

I would not run anymore than 11-12 psi. I also run a VF29 and it is a big upgrade from the stocker. In your case, I would be afraid that the egts would get too high and roast the cat in your down pipe. I was at 100% idc all the time before I installed new injectors. And that was at 15-16 psi! Any time I went above 4500 at full throttle the idc would soar. Get some injectors asap!

[Red Rocket]

Originally posted by Camperguy

The guy I bought this turbo off of was running "No fuel management at all"and was running full catless exhaust with dumps and MBC@16psi for over 15,000 miles ....Well regaurdless I`ll probably wait till I get all my pieces together and send out my ECU for a Cobb reflash while I install the stuff.

Thanks Bill

I'll jump in here because I am the guy he is buying the turbo from.

I ran the VF29 on the street using the stock boost control 99% of the time, and the stock ecu all the time. I also installed a walbro fuel pump to keep fuel pressures up just in case. Before the wastegate was ported, it would run to 12 psi at redline due to boost creep, and would creep to 16 psi+ with the catless exhaust cutout open. After the porting, it would follow the stock boost curve perfectly. I only made about 3 pulls where it creeped really bad with the cutout open.

At the track, I have used a mbc at up to 16 psi to redline, on a hot day with 100 octane fuel, I'm pretty sure the car did not lean out. I ran about 14.5-15 psi with 100 octane on a cooler night and ran back to back runs of 13.39@99.8 MPH, and 13.4x@100.x mph.

For Bill's situation, I would check on that boost control the unichip runs - I'm not familar enough with them. If it does work, that's great. As for acceptable boost levels that it would provide, I would think 16 psi in the midrange would be okay, as long as it tapers down to 13 or so by 6000 rpms. I really don't know enough about the unchip, but I would think it should be able to handle fueling the somewhat denser air the VF29 is pushing, at the same boost levels. Otherwise, I wouldn't see a problem running a straight 14 psi to redline with a MBC in hot weather, but turn it down to 13 psi or less when it's cold.

I don't see any problem with running the stock downpipe, it's not optimal, but you shouldn't have a problem with it. You should not have any high egt problems with the boost levels discussed above.

Kevin