My new ride, Turbo 98 neon

[ShadowFromHell]

Just bought this last night. Its a 98 sport coupe with a 127k. Fully loaded, power everything. Is powered by a DOHC 2.0 with a stage 1 Hahn turbo kit (16g turbo) that has had a SRT FMIC added. It is SUPER clean. Cleanest neon I have seen in a long time. Its currently running 4psi, NO boost gauge, WB02 or even NB02. First order of business is to get some gauges in it. Then I am going to turn the boost up to 8-9psi and drive it. I am also going to swap the brand new KYB GR-2's and ACR springs off of my beater coupe onto this one. This spring I am going to put a set of 6.5 crabs and 225/50s on it. Hahn claims it should run 13.0@105 on slicks with this kit. I will be finding out this summer! . Tomorrow I am gonna get some more pics.

Dustin

[cordes]

Congrats on the car! That sure does look clean. I would love to have one like that.

[shadow88]

Anything done to the bottom end to handle the turbo? What are the electronics controlled by?

[Vigo]

Nice! I like it!

Normally i would be totally against putting crabs and 225/50s on a neon but since this one has a turbo it will probably still be faster than a stock neon even with 45lb wheel/tire on it..

[turbovanman²]

Awesome, congrats. Any engine pics?

[ShadowFromHell]

No new pics today. Spent 9pm to 3am in the ER with my wife last night. Everything is fine but I was just too beat today to do anything. Maybe tomorrow. Its on a stock bottom end but the motor was rebuild 8k ago, so at least its fresh. Since its a Hahn kit it uses a RRR setup for fuel. Not the best I know but it is a proven system on these cars. Im not too worried about the bottom end at this point. The long term plan for the car is to get it tuned to 8psi which is the "safe" number from all the research I have done over the years for a boosted DOHC. Im thinking of also swapping to a SOHC ECU before I tune it. They add a little less fuel, but also run less timing and I can add the fuel back in. But after I get that done I am going to start saving up for a OBX diff and a new clutch. It doesn't need a clutch but its a stocker and I might as well do it while I have the tranny out. I think a OBX diff will actually give me better performance on the street then swapping to a build bottom end and more boost. The reason Im thinking of putting crabs and 225/50s on it is I have both already. On the 4psi it is running it will still smoke the skinny stock tires on demand, it needs some fat tires! Eventually I will buy some lighter weight wheels for it, I agree that putting heavy wheels on it are a bad idea, part of the reason my other coupe has stock wheels on it. They are just so dang light!

[shadow88]

So something like a zener diode is used to prevent the map sensor from reading out of range and shutting off the fuel?

My concerns are with the ignition advance with a boosted engine and stock compression ratio and pistons. And the facotry computer is expecting something like 44 psi fuel pressure at all times and pulsewidth is based on that never changing value. I understand you can easily add enough fuel when in boost, but what about low vacuum situations. Your RRR uses a vacuum signal, correct?

[ShadowFromHell]

Actually I have to check into what is stopping the map sensor from seeing boost. It is throwing a code, and I dont know if anything was added to address that. I have a map clamp in my toolbox so if it doesn't have anything I will be adding that. The RRR does not have a vacuum signal. It has a boost signal with a check valve in it. Neons use a constant pressure from the factory, it never changes. So as long as the math has been done on what to set the base pressure at so they injectors are flowing the same as a stock injector would be, out of boost it is just like any NA neon. When the boost comes on that's when things change. The bad thing with this system is no timing control and thats why its limited to 8psi. From what I understand over 8psi they just have to much timing and it causes detonation. A MSD boost retard box can be easily used to pull timing though and I plan on getting one. Same reason I want to swap to a SOHC ECU, they run less timing then a DOHC ECU. It may seem like a hokey setup but since the Neon ECU is yet to be hacked your options for boost are a RRR setup, or a standalone. No other way to do it.

[roachjuice]

So something like a zener diode is used to prevent the map sensor from reading out of range and shutting off the fuel?

My concerns are with the ignition advance with a boosted engine and stock compression ratio and pistons. And the facotry computer is expecting something like 44 psi fuel pressure at all times and pulsewidth is based on that never changing value. I understand you can easily add enough fuel when in boost, but what about low vacuum situations. Your RRR uses a vacuum signal, correct?

Three things control knock. Fuel. Boost. Timing. Turn fuel up to flood it and not see knock. Turn boost down. Turn timing down.
What I'm getting at is as long as he has enough fuel, he shouldnt see detonation. That's what Gus and gary did back in the say. Rising rate regulator and an adjustable fuel pressure regulator. Worked great on the slugmobile. 12.2's@113. Fuking a all day.

[shadow88]

Three things control knock. Fuel. Boost. Timing. Turn fuel up to flood it and not see knock. Turn boost down. Turn timing down.
What I'm getting at is as long as he has enough fuel, he shouldnt see detonation. That's what Gus and gary did back in the say. Rising rate regulator and an adjustable fuel pressure regulator. Worked great on the slugmobile. 12.2's@113. Fuking a all day.

Well technically one thing causes detonation. Too much cylinder pressure for a given octane rating. Too much fuel is still too much, even though it slows the burn time down to prevent maximum cylinder pressure at TDC , it's a tried, tested and inefficient way to control detonation. It also causes premature piston ring and cylinder wall wear.

Less boost? Where's the fun in that?

Less timing allows proper mixtures for maximum cylinder pressures at the correct crank angle.

I'm sure Dustin has a good idea of what it takes to make reliable power without sacrificing engine components. Good luck and keep us informed on how the car's doing. By the way is this a daily driver?

[contraption22]

If memory serves, Hahn used a check valve installed between the intake manifold and the map sensor to prevent the MAP from seeing positive pressure.

The neons used a dead head fuel system in stock form, and had no vacuum reference to the FPR, which was located in the tank.

With the Hahn system, a return line was added, and the RRG was added in line, but fuel pressure is not reduced with vacuum.

[Vigo]

I recently worked on a hahn system on a 420a eclipse and it was exactly as Mike describes, as far as i could tell.

[ShadowFromHell]

Problem is the map sensor is IN the intake manifold. So you have 2 options a "missing link" that went between the map sensor and intake, or a map clamp. Ive been around turbo cars long enough that I feel comfortable raising the power some. After getting the ER bill it might be a while before I raise the boost but a buddy of mine said that I could borrow his spare WB02 to at least get its current setup dialed in. It also feels like it might have a boost leak so Ive got to look into that also. Ive spent the last couple days hunting for injectors that will meet the power goals, but still not have a super low base pressure. Turns out, our log 27's are about perfect. According to the fuel injector calculator I will need a base pressure of 33, and at 90psi I will have enough injector for 240hp. Should be perfect, and I have a few sets. To run 8psi hahn left the stock injectors in and said to shoot for a fuel pressure of 105! Scary!

[shadow88]

The neon is a high impedence fuel injector (about 12ohms) compared to our old fashioned 2.4 ohm injectors. The sizing may be close, but I think you'll find the injector driver circuit won't operate them, or if does, the additional current will burn up the driver circuit in short order.

I think the best injector would be the staged injectors from the srt-4 neon. But they're shorter and will need a custom fuel rail to work with your DOHC intake manifold.

[Vigo]

I think you will have to space the fuel rail out to fit the old injectors, i seem to remember most 2.0 injectors being the shorter ones.. Could be wrong.

a map clamp is just the old diode thing people do on TMs. I would see what your map sensor sends back at full atmo pressure (i.e. key on engine off) and if it's over 4.7v i'd just put a 4.7v diode in it.

[ShadowFromHell]

Ive got a map clamp in my tool box. No big deal at all to install, just have to make sure there isnt something there already. I understand the impedance issue, I plan on using either a honda or DSM resistor box. Even stage0's from a srt would require a base pressure of 12-18lbs. To me that just seems WAY to low. Ive found the injectors used in LS1's/LQ9's are 26lb and would work good but am having trouble finding a set and havent figured out if they are high or low. I could always go the mustang 24lb route, but I think those might be to small. Just got to play with it and see. Its a delicate balance between enough injector and a high enough base pressure.

[Vigo]

Well whatever you do just dont spend $400 on it or then you could have just bought an AEM FIC and then had your map clamp, injector scaling, built in 3 bar map, datalogging, timing retard, and nice tuning GUI all in one. And some other stuff im forgetting.

[dodgeshadowchik]

Dang.. the sunroof appears to be in working order!

Congrats, car looks clean! Have fun!

[ShadowFromHell]

Dang.. the sunroof appears to be in working order!

Congrats, car looks clean! Have fun!

Yes it is .

[ShadowFromHell]

Snagged a picture of most of the fleet today. Has the rear of the neon so I thought Id post it here. All Mopar FTW!