Boost vs. Timing

1563 Views 6 Replies 3 Participants Last post by TheBlade, May 20, 2002

TheBlade

Discussion Starter · May 14, 2002

Does anyone have an idea of how much boost I could push with only swapping to colder plugs on a stock 93 GT ?

I know I cant really go any higher then 5lbs because I´m also going to be on stock injectors and fuel pump for awhile, but do you think it would handle the 5lbs with out pre-ignition ?

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MXTurbo

· #2 · May 15, 2002

I think you might be OK. My ´93 with 92 octane and a 55 shot of N2O doesn´t ping.. through 3rd anyway. Never squeezed in 4th or 5th, you might get some ping with 5psi there. Are you using a boost dependant FPR after the stock one? That will get you more fuel pressure, but not sure how much flow the stock fuel pump is good for, so it might be a mute point. What size turbo are you using? My MX-6 with the little RHB5 IHI could run 15psi, no ping, but with the .60 trim T3 it pings like crazy at 12. The turbo size will have a lot to do with it. Are you using an intercooler? Is there a link somewhere where I could read about your setup?

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TheBlade

Discussion Starter · #3 · May 15, 2002

Cool, thanx for responding...okay here´s the setup and reasoning. I will be using a front mount (starion intercooler). I´m using an IHI RHB5 -VJ20 (323 GTX) turbo.

Im kinda stuck, I need to make a trip to Cali for June 13th, and I dont want to go out there and not be turbo´d (I figure if I´m going for a weekend I´m going to have fun).

I know my stock injectors aren´t going to deal with the 10lbs I want to push. In fact the stock (2XX cc) injectors wont handle more then 5 or 6lbs. I´m pretty sure the fuel pump will be okay (but I´m planning on getting a new one anyhow).

To solve my fuel map prob and ignition prob I was going to get a 323 GTX ECU. I know those ECU´s like to go lean at 11lbs, so I figured 10 would be a good limit. But I wont have the cash for one, so I was thinking of just skipping it until I can afford it.

So.... I know fuel will okay up to 5lbs, but I´m wondering if the timing advance on my GT Ecu will be okay up to 5lbs provided I´m on premium gas.

In the long run I will be using an MSD BTR and Apex S-AFC (you know when I have a nice weekend in Vegas or something).

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MXTurbo

· #4 · May 16, 2002

I bet with the VJ20 you will be OK. That is a pretty small turbo, of course you will have the stock compression ratio which will make it a little more "ping prone". You could also back off the initial timing a few degrees if you hear some ping. I wonder what all is compatible between the old probe/MX-6 turbos and the escort? They look to be very similar to me. I bet you could find an old mx-6 turbo and use the intercooler and piping and it would fit pretty much like it was made for that car. Another thing the MX-6/Probe GT injectors are 325cc´s and the stock fuel pump is good for 180whp. Also, the stock turbo is an upgrade for the GTX, so that would be a future mod for you and there are several other cheap IHI turbos that I know fit the MX-6. I´ve done about every imaginable mod to my MX-6 so I´m pretty well versed in the turbo game. Instead of getting all those piggyback systems you might want to consider investing in a stand alone engine management system, like the SDS system. It´s very reasonably priced and after the S-AFC, ECU and MSD boost timing master you might even be money ahead with the SDS -- and with unlimited tuning potential. Well now you´ve got the gears in my head turning, the BP motor in our Escorts are extremely overbuilt by mazda, I want a turbo on mine

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Onegimp

· #5 · May 17, 2002

The stalk turbo on probe gt´s and mx-6 turbo´s are VJ-11´s, you would be down gradeing if you went with one of those over the VJ-20.
Denis

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MXTurbo

· #6 · May 19, 2002

<TABLE BORDER=0 ALIGN=CENTER WIDTH=85%>[TR][TD]Quote:

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On 2002-05-17 13:07, Onegimp wrote:
The stalk turbo on probe gt´s and mx-6 turbo´s are VJ-11´s, you would be down gradeing if you went with one of those over the VJ-20.
Denis

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I always thought that too, but someone I know who is a GTX "expert" told me the stock VJ-11 is an upgrade. I know the VJ-17 in the T-bird is an upgrade for the VJ-11, so numerically it seems like the VJ-20 should be bigger. From what I have heard though, it isn´t.

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TheBlade

Discussion Starter · #7 · May 20, 2002

Well either way, I already have the turbo and it was the turbo that mazda chose to put on the BP 1.8 so I figure their engineering can´t be too bad.

Yeah my ultimate goal would be an AEM programmable ECU. But those are like 1200 alone and well I´m eating top ramen noodles this month because I bought the turbo.

For the intercooler Im almost positive I´m going with an old starion/conquest FMIC. But the goal is to get 5lbs running, then assure myself that the fuel system and timing will work at 10lbs. 10-12lbs was my goal for the street.

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