My goals are simple: Street car. Stock motor. Stock turbo. Early spool-up. Make as much power as possible under the curve. Broad torque band, not peaky power. Drivability rules! I’d like to make an honest 320whp on the local Mustang dyno.

Caveats: I’m on ACN91 fuel. I’m in the desert where a conservative tune will be in order. I do not list an MBC, as I’d like to let the ECU control boost. (If not satisfactory, I can always add the MBC later.) I prefer to stick with the OEM intake due to the extreme under-hood temps in the desert. I want to stay with the 9.8 hot-side for the improved spool-up.

So far my mods to a recently acquired ’03 VIII are:
Autometer boost gauge
K&N drop-in
Forge by pass valve
Helix down pipe
Helix test pipe
Greddy EVO2 cat-back
NGK copper spark plugs

Purchased, but not yet installed:
HKS 264/264 cams
SS O2 housing

On shopping list:
Nisei LICP
Walbro 255Lph fuel pump

Obviously, a tune will be done after all the parts are installed.

Would the following mods be helpful to my goals, or do they only benefit at the very peak of the power curve?
1. ported exhaust manifold
2. UICP
3. FMIC
I searched, but did not find any individual dyno data on these.

Thanks,

 

The Upgraded FMIC is more of a safety mod than anything. It's a pretty good idea since you are in a mostly hot enviornment. I reccomend the buscher or the AMS race FMIC. Im not sure if you will see any gains from porting the stock exhaust manifold for the amount of work it is. Definately a yes on the fuel pump and the tune. If you really want to make your car a beast, try alcohol with the appropriate safe guards. Of course the safe guards can cost some money. It all really depends on your budget. Good luck and keep us posted!

 

You should buy a 10.5 hotside and P&P it and at the same time P&P your exhaust manifold. The 9.8 hotside sucks, you will see a good bit more power from the 10.5 hotside and it spools just as fast. You should get the Nisei LICP and get a UICP too. Then get ALKY Injection, you will love it. And to wrap it all up get a custom tune.

 

Hi Jim, for the price of those 3 parts, would you consider this:

https://www.evolutionm.net/forums/sh...56&postcount=1

You will make more safer power. You will have a REAL hard time limiting your car to 320hp on Stephen@IAPerformance's MD

 

I say yes to the 10.5 hotside. The turbo still spools fast. Buy an intercooler off ebay and leave your stock upper pipe. The LICP and tune is a must.

 

sorry to get off the subject but are those ebay FMIC any good?

 

I think your mod list is very good. I do believe you'll want the FMIC due to the desert heat, but I do not recommend getting an Ebay FMIC - go with the BR Deluxe or AMS or Nisei. I think you'll want an MBC, too, but if you go with the ECU-controlled boost, just remember that you have no control over it if you need to change it, and you can't really raise it - it will just be near-stock boost with less taper. The only way to raise the boost is by manipulating the restrictor pills in the boost lines, which then causes a more erratic boost curve, but it can be done.

I don't know what led you to that specific exhaust combo, but you could get a full TBE from one manufacturer within a package to save money, make great power, and save weight. If you stick with the ones you already chose, it won't be a bad thing, though.

Don't put in plugs randomly. Put them in when your nice stock Iridiums fail. If they have already fouled, then use NGK BPR7ES gapped to .026 or so...

Keeping the 9.8 doesn't give you better spool really. A 10.5 hotside that is ported and coated will be a nice addition that helps the entire powerband without hurting spool.

 

KawRider,
Agreed on the FMIC as insurance in the extreme desert heat. What do you think of the Turbo XS FMIC? For $585.00 it looks like a pretty good value, but I've never actually seen one.

SlowCar,
To tell you the truth, I put alky and NOS in the same category. You either have to keep the bottle filled, or keep the bottle filled. That said however, I would consider any upgrade that was proven to be a good value. I just don't recall seeing a B4 and after alky kit dyno test, but I'll be looking for one.

Warr,
I'm actually not so crazy about the quality of the sound from the Greddy EVO2 cat-back, but I am very pleased with the volume. And, so is the wife. She despised the sound level of my previous car and would seldom ride in it. She thinks the EVO sounds just right. The EVO2 was recommended to me by several local EVO owners who had previously been running name-brand LOUD exhausts, but had grown extremely weary of the drone. You may be right on the MBC. Do I need to add it prior to a tune, or can the MBC be safely added after?

EVO8904, prj.evo, Warr
I'm going to hold off on the 10.5 hot-side for now. I've been following the threads on the 20G-9LT / EVO Green turbo with great interest! I'm very value focused, so I'll do whatever gives me the most bang for my bucks.

 

- 10.5 hotside is a bang-for-the-buck mod, and it is not relevant to the 20g-LT.

- Alky is nothing like nitrous. A nitrous bottle will run out very quickly, but a 1-gal alky tank will last you 2-3 weeks or however long it takes you to go through 2 tanks of gas with frequent boosting. Also, you have to fill up your gas, right, but that doesn't bother you? You fill up the alky less frequently than gas, so that should not deter you. Before/after dynos? You hardly need that - there's no question that alky is a HUGE boon, especially for people on 91oct, because you get to run much more boost and more aggressive timing. There are plenty of dynographs showing this, but it's not a mod where you need proof from dynographs - it's just a known fact.

- Put on the MBC and set your boost FOR the tune; don't add one after the tune.

 

Bang for the buck...

10.5 hot side around $250
Alky Injection around $500

both are proven to be very good mods and make alot of power. Let say with all the mods you have now and you buy a EVO Green for $1700. Do you really think that you would make more power with that turbo than if you bought a 10.5 hotside and alky injection? I know you would not.... IMO the EVO Green should come later and it is not much bang for the buck.

 

Yeah, I agree with everyone that a ported 10.5 HS is a good power adder and that surprisingly it doesn´t detract from quick spoolup as you´d think it would. When you install the O2 hsg. you should do the HS at the same time and also it would be the moment to port your exhaust manifold.

 

Jim in Tucson, we are giving you very good advice. I wish I would of had people giving me advice when I started modding my car. Soudns like to me you need to use your search engine. IMO alky injection is the best BANG FOR THE BUCK mod you can do.

 

Added to shopping list:
10.5 hot side
MBC
FMIC (before summer)

I'm giving up a sports car in order to own a much more practical sedan. For now anyway, the alky injection simply does not fit my definition of practical. Perhaps after I run out of other bolt-on mods to add, my thinking will change.

Thanks for all the great advice.

 

Jim, swing over to stephen@IA and ask him about the aquamist kit he put on a silver evo last year.

Alky is not like nos....you got failsafes - flow sensor and float sensor on a alky system, one to tell you its time to add alky and the flow sensor will not allow the car to boost above WG pressure if there is NO flow, LO flow and HI flow, only in the safety operating area the car will run extended boost.

 

Mine works plenty good for me. My brother also has it on his evo, and he made 352 whp with his, which is at or around or more than what it looks like you are trying to make. It was also 150$ shipped, which saves you enough money to buy the 10.5 hotside and then some.