No more "Hacked MAF"...

[:: orion ::]

No more Hacked MAF for my S14...

Why? Well, I wanted around 250-280rwhp to be able to do what I like with the car, which is auto-x and HPDEs, specifically Sebring and Road Atlanta Track Days.

The Hacked MAF setup worked great on the street (EGT's were a little high), and did well at local auto-x and the higher speed stuff that a local group does, plenty of power and TQ, great response, and seemed safe, other than the EGT issue.

I had the car tuned with: 4-bar base fuel pressure, 370cc injectors, 2.875" ID MAF, and 9psi from a T3/T04E...I'd bet it was in the 255-260rwhp range. ~11.5:1 A/F under boost via my TechEdge II.

And with this setup, I was running 100% duty cycle, and 5.11 MAF volts on the short Gainesville Raceway Roadcourse...too "on the edge" to be safe.

But, I went to Sebring with a friend of mine (who's an instructor there for CHIN Motorsports), and we got to do a few test laps. And I found that after one lap (~3 minutes), the EGTs were OVER 1400F (probe is AFTER the turbine housihng), so we took it easy for a lap, only did 80mph on the back straight, then hit it again, only to get the same REALLY high EGT readings.

Now, this pretty much convinced me I had to make a change. I need to be able to safely run the car on road courses without melting my poor, stock cast pistons...otherwise, the car is useless to me. I need it reliable and quick...

Luckily, aside from the injectors, I chose the rest of my turbo parts with more HP in mind...GReddy VSPL can do ~400rwhp, T04E 57-trim can do 400 if needed, etc...no other limiting factor other than fuel..and with more fuel and boost, I needed better timing control.

My options:

555cc injectors, Z32 MAF, S-AFC, and MSD BTM to control timing. That'd be ~$1200 in parts if I could find stuff used...

- Or -

JWT ECU, 50lb injectors, Cobra MAF, Top Feed Rail. $1100 at the cheapest, if I had to get a new ECU, then used injectors and such.

Neither seemed good, until I found a reasonable deal in the FreshAlloy classifieds for the JWT setup...

- - -

So as much as I've *****ed about JWT in the past, I'm back running their ECU. Now, the reason for my *****ing before was that the timing was WAY too conservative for only 7-8psi, like I ran before. It's still conservative, but at least fitting for 12psi and up.

I got everything installed a week ago (wired up new injector clips, had to make new brackets for the fuel rail, new MAF plug, etc...) and it started right up.

Set the base timing to ~22 (might as well take advantage of the conservative nature of timing curve under boost/load, and get better off-boost response!) and took it for a test drive, still at ~9psi.

Car was obviously slower, as my dyno showed last year (JWT 370cc program made 9 less RWHP and 20 less ft/lbs over the range from 3500-5500 vs the Hacked MAF setup at 8psi)...still the case here. Spool is worse, but not that bad. Maybe ~200rpm slower, and it comes on smoother, not like a hammer as it did before.

So once everything checked out, I upped the boost to a more appropriate 12psi, and took it out...oh yeah - Good stuff. My 57 trim is a little more efficient at that boost level, on top of the extra boost...so it feels great. MUCH faster, and the EGTs are more like ~1200 at WOT through 2-3-4th, as opposed to ~1350 before.

I'd estimate ~280rwhp, based on other people's dynos with similar setups (IIRC, "TY" made 318rwhp at 1bar, and "Miami240" did 310rwhp at 14psi).

- - -

I'm actually very happy with the car now...I can beat on it with (almost) no fear of blowing my motor, and I can run the events I want to do...again, based on the experience of others with the 50lb program, drifting, AZ heat, and track days don't seem to limit reliability or safety.

- - -

Also, put the wideband in for a quick check today...A/F at idle is ~15-16:1, cruising is right at ~14.8-14.9:1, and under boost is quickly drops to 12:1 as it spools, then 10.8:1 at WOT. A little rich, but safe!

- - -

Anyway, just wanted to share, sorry for the longish post.

I'll get some pics soon...

- Brian

[Tictakman]

sounds like a good setup. im thinking about going the jwt ecu route but im waiting for dsmsucks to get his product out. im interested to see what he has to offer first. have you thought about his management?

Zak

[:: orion ::]

Looks like it only controls fuel...why not just 550s and an AFC???

Worked for tons of other KA-Ts...

And my Hacked MAF accomplished the same goal, and had tunability via fuel pressure...but at a HP level nearing 250rwhp, you HAVE to get better timing control. That, and with a stock ECU, you still have a rev limiter at ~6800...I like the extra 400rpms that JWT gives me.

Anyway, I don't mean to knock it...but the GM MAF translator was exciting in the DSM camp a while ago, and isn't widely regarded as a great tuning tool now from what I've heard...

- - -

And I'm not a JWT fan...I kinda don't like that I have to run their products...but their stuff is good. Their cams rock, the engine management makes OK power, but is SAFE...I'm OK with that. Would I buy it all new, and pay retail...NO, no, NO!!!!

I got my whole new setup (ECU, injectors, MAF, rail) for a little more than a set of new 550cc injectors...so I won't complain.

- Brian

[Tictakman]

understood, got any more links to the deal you got? im interested too, id rather have a proven system over something i have to trust on my own tuning until i get to a dyno.

Zak

[andrave]

I have JWT waiting to go in with my new engine....I'm using z32. what mafs are you using?

I'm also using 50 lb msd style.

[:: orion ::]

JWT ECU, 50lb injectors, Cobra MAF...

Hehehe...

Specifically a stock '93 Cobra MAF.

- Brian

[Jookmasta]

good to actually hear some positive feedback on the jwt ecu. everyone usually complains about how conservative it is but there is that safety issue to consider. i guess it does seem better to have the ecu control timing or do what it needs to do to operate in a safer range.

my question to orion is what made you choose the jwt way (besides finding the good deal) over say using an SAFC and a BTM? ur injectors arent too big so it could be compensated by the safc and the btm couldve done timing for ya? or what also made you choose the jwt route instead of the emanage? i mainly ask b/c im now on the hunt for something to control my timing and most of the people down here seem to run jwt. i hear mixed reviews to everything and price seems to be the determining factor. i wouldve thought personally that peeps would want the adjustability. any insight would be greatly appreciated.

[klattr1]

do u know what kind of timing numbers you are getting WOT?now you can reach 300-330 rwhp if you wanted to. yeh.

[bbandit]

Orion, are you still running on stock un-openned KA block?I'm thinking about doing the same thing too.I hate these 370cc's... they limit my need of pressurized air.

[:: orion ::]

jookmasta -

MSD BTM, plus AFC, plus Z32 MAF, plus side feed 550s...same money as a proven setup. Plus, with many piggy backs and band-aids, it simply cannot be as reliable and simple as a retuned ECU.

I want to be able to drive the car hard, not tune it, and drive it while I worry...then tune some more, etc...I'd rather focus on driving rather than tuning.

- - - - -

klattr -

With my 370cc setup, it was:

Retarded 5 degrees at idle with the TPS plugged in (i.e. base at 20, but read as 15 by the gun nce I plugged the TPS back in...)

Good under cruising, anywhere from 30-45 BTDC under light load.

Dropped to 15-16 with ANY stab of the throttle...then fed back a degree or two as it neared redline.

Too conservative for me, so I have my base set to 22, since I'm only running 12psi...

- - - - -

bbandit -

Yes..90k motor out of a '95...still blows +180psi compression across the board.

I'll never run anything but a stock block...I don't need that much power, and stock can handle plenty.

- Brian

[:: orion ::]

...got any more links to the deal you got?

Nope, it was a used setup. I rarely by anything new...I like good, proven stuff...but I'm frugal enough that I wait for deals before I upgrade (usually).

- Brian

[assnailer]

If you have been screwed in any way "fianancially" from NIGHT7RACING, you may be in luck!!! If you want you money back plus interest I will be "spearheading" a huge class action lawsuit against this kid and family. Here is what I need you to help with. Do searches, call people and find as many people as you canthat have been screwed by this guy. I need names and numbers tell them you have someone that will get this stuff resolved! This is a very fraudulent case that is currently being investigated by many!

[red240ne]

wrong forum bro

[andrave]

I got my JWT tuned for an sr20 for 350 shipped. Some guy decided to quit his SR project and since the sr ecu is just a retuned KA one I bought it and sent it back to JWT for retuning, and I even got some free decals and a pimp license plate frame. sweet.

[red240ne]

If the AEM EMS never comes out, then I'm tempted to go the JWT ECU route....Either that or buy a wideband, and tune myself...JWT is tempting tho..

curt

[hannibal]

Orion,Would you still recommend the hacked MAF over JWT for low boost situations, especially where budget is a big factor?I'm kinda confused about your previous setup. I just saw you were running 4 bar base pressure. How were you able to do this? The whole hacked MAF theory is based on increasing the MAF in proportion to the increase in injector size. But how does this 3bar vs 4bar base fuel pressure come into play??

Great post by the way...

[:: orion ::]

Yes.

Again, it's manily due to the timing curve...it's so rediculously conservative that for 7-8psi, your losing A LOT of power

See, timing should be based off of your boost level...for example:

A KA at 8psi needs about 3 degree of boost retard to keep from detonating...based on using no timing retard for up to 2psi, then .5 degrees of timing backed out for each additional pound of boost.

Now, we'd like this to be dynamic, and change as the boost changed...but for that, you need a standalone with a MAP sensor, not a MAF setup. MAF setup approximated this based on load (aiflow) vs TPS voltage.

And bear in mind that there's base timing (20 BTDC), and then there's total timing, which the ECU controls...it adds or subtracts from the base of 20 as needed. A N/A KA probably gets 25-28 degrees of total timing under full load, WOT. Now, from that TOTAL tming is where we need to make our changes...meaning that for 8psi, we shuld be around 22 degrees total timing to be safe.

So JWT gives about 16-17 degrees of TOTAL timing for their 370cc program...that's probably 5-6 degrees of extra timing retard, which is enough for 14-15psi!!!!!

- - - - -

Anyway, the Hacked MAF is no better than an AFC...all it allows you to do is add bigger injectors. it's just cheaper and has no adjustability, except fuel presure if you add an adj. FPR...

And that's what I did: Added 14.5psi of fuel pressure to over-run the injectors...bascially, that makes a 370cc injector act like a 412cc injector. I used a bigger Hacked MAF tube, more fuel pressure, and tuned with my wideband to get to 11.9:1 A/F ratio under boost.

Hope that helps - Brian

[hannibal]

Wow, I now understand how the ECU controls timing. And I didnt realize you set your hacked MAF size based on the 4bar setup.Thanks