LT1-LT4 Modifications 1993-97 Gen II Small Block V8

FAST XFI and LT1 users - please come in

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Old Aug 4, 2012 | 06:47 AM
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Default FAST XFI and LT1 users - please come in

Tired of my stock PCM with 2 bar and 10psi Procharger and LTCC coil conversion.
It's close - but I have no tuning support at dyno shops and my PCM is acting wierd with coolant temp readings jumping around and the forever learning and tuning limitations are frustrating!

if I buy the kit - only found one for LT1 on ebay for $2065, I'll no doubt need this installed by a pro and tuned at a dyno shop.
How the heck do those guys create a 'base tune' before firing up the engine?

How 'plug and play' is this?

the harnesses actually plug right onto the injectors and right into the opti?

I have a th400 so trans tuning is no concern.

does the controller also plug into the cars harness = a/c AND FAN CONTROL?

JUST A BRIEF OVERVIEW OF WHAT TO BUY AND HOW IT ACTUALLY PLUS INTO THE CAR WOULD BE HELPFUL
I READ A BUNCH OF THE MANUAL ONLINE - LOOKS LIKE TUNING it will be like learning Tunercat and Datamaster all over again.

Please share your experience
thanks
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Old Aug 4, 2012 | 12:18 PM
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It's not plug and play. You can get the XFI box for about $1600, and a bunch of places make harnesses for integration that vary in price, usually about $450 or so (Paid $475 for mine in 2006). The injector harness is nice because other than two connections for the pink wires from teh factory harness, it's plug and play right into the injectors.

As for the tuning, the XFI comes with several base tunes. Just find the one closest to your setup, set the constants that need to be changed (displacement, injector sizing, ignition setup) and it should fire.
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Old Aug 4, 2012 | 02:02 PM
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Not plug and play at all. You need the box, the main harness, the injector harness, the opti harness, and then it still needs a cam signal. If you run an OBDII car it will have a crank sensor, if not you will have to figure out a way to run one, or go with a distributor will dual sync. Figure around $3000. Ask Mike V on here, he will know more.
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Old Aug 4, 2012 | 07:02 PM
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Originally Posted by Fastbird93
It's not plug and play. You can get the XFI box for about $1600, and a bunch of places make harnesses for integration that vary in price, usually about $450 or so (Paid $475 for mine in 2006). The injector harness is nice because other than two connections for the pink wires from teh factory harness, it's plug and play right into the injectors.

As for the tuning, the XFI comes with several base tunes. Just find the one closest to your setup, set the constants that need to be changed (displacement, injector sizing, ignition setup) and it should fire.
OK on that...clarification on harnesses asked below, are you running an opti?

Originally Posted by joelster
Not plug and play at all. You need the box, the main harness, the injector harness, the opti harness, and then it still needs a cam signal. If you run an OBDII car it will have a crank sensor, if not you will have to figure out a way to run one, or go with a distributor will dual sync. Figure around $3000. Ask Mike V on here, he will know more.
soo...
main harnesss = from box to factory sensors (temp, IAT, TPS, MAP etc??)
injector harness = from box and (two pinks from PCM) to the 8 injectors?
opti harness = from what to what?

I only utilize the optical sensor in my opti to the PCM with the LTTC conversion box - OBDI - what gives the cam signal in stock PCM formation? Can I tap that and send to XFI box?
Or from my LTCC box perhaps?

I feel a distributor is not an option - can't get into manifold mods and the location is a killer - I don't work on my car due to disability - I need to pay for the install and try to understand / provide enough insight and correct parts to the builder, probably at a dyno shop that tunes XFI among others and does installs, but of course who has any LT1 experience? lol.
Thanks so far.....hope this is a viable solution over the 24x LS1 PCM conversion - that seems like as much work with just another GM computer. In fact, I think I read that conversion won't work with OBDI or an opti - I forget...
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Old Aug 5, 2012 | 02:21 AM
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Brian Macy builds harnesses for the XFI, I had one on my car and it was pretty straight forward. You get a pigtail harness from the box and just cut into your factory harness.
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Old Aug 5, 2012 | 03:07 AM
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Originally Posted by Speed Density
Brian Macy builds harnesses for the XFI, I had one on my car and it was pretty straight forward. You get a pigtail harness from the box and just cut into your factory harness.
Cool - how do I get ahold of him?
thanks
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Old Aug 5, 2012 | 07:04 PM
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Well, you could google it. He isn't a sponsor so I'll leave it at that.
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Old Aug 5, 2012 | 08:58 PM
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Yes I'm running an opti, and Brian Macy is who I got my harness from too.
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Old Aug 6, 2012 | 07:08 PM
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Thanks for your help all
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Old Aug 16, 2012 | 06:00 PM
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FYI update:
Because I have converted to coil per cylinder with the LTCC kit - I need a cam and crank signal as mentioned above.
Also need an XIM module/harness.
All told ~$3600 plus installation/tuning.

As much as I'd love to, a 24x conversion to an LS1 ECU is more affordable, and will probably solve my old LT1 computer concerns just as well for a street machine.
Thanks again to those that helped me out.
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