10lbs of boost on a stock 305TPI with 19# injectors, and a Bosch in line fuel pump.

Whats a good pulse width to have on the injectors?

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91 Formula
305 TPI 5speed
1LE/G92/WS6
w/GTA gfx,rims,hood

Paxton-charged,Cold air ind. w/K&N, SLP airfoil, ported/polished plenum, March pulleys, Crane AFPR(43psi),Crane Gold 1.6rrs,MSD coil,MSD6AL, Holley 9mm wires, fastchip, Bosch O2sensor, SLP headers & catback,short shifter,3:73s w/Auburn posi,160* t-stat,JET 195* fan switch, Macewen white face gauges, Autometer gauges, Zoom hi-performance clutch.

[This message has been edited by theformula (edited January 28, 2001).]

 

Or would I be better off with 24 injectors and decreasing pulse width?
Anyone?

 

It's a little more complicated than that. You have to calculate how much TOTAL fuel you need, and then pick an injector size and fuel pressure that will allow you to operate no more than 80% of the duty cycle of the injectors through out the operating rpm range of your engine.

Supercharging also introduces other "tuning challenges" for both MAF and SD cars with the stock ecms. With your 730 SD ecm, you only have a 1 bar MAP; you really need a 2 bar MAP and the SD 730 ecm cannot be modified to handle a 2 bar MAP. Thus you are "flying blind" and have to make corresponding changes to the VE tables to compensate for this @ WOT.

Grumpy has a lot of knowledge in this area and hopefully he will drop by and give some input on this. I would go with what Grumpy recommends. I think there are some posts on this very topic on this board and the "Power adder Board". Do a search on this board on "supercharg(ing)" and other similar keywords. It will give you some insight into this subject.

[This message has been edited by Glenn91L98GTA (edited January 28, 2001).]

 

I'm following Grumpy's suggestion to switch from my 165(MAF) to a 749(Syclone) ECM. I'm also going to a new harness from Painless for a 730(SD) and make any changes to the pinouts instead of reworking a 13 year old harness. Excellent software is available at www.syty.org site. Andy Whittaker's FreeScan has been recently updated to include the Syclone/Typhoon ECM. I've found the ECM's to range in the $50 to $100 range less EPROM. I beleive that a MEMCAL for a Syclone/Typhoon must be used. Hopefully by late spring I will have all the parts sourced and exhaust work finished on my turbo/tpi. A question to Grumpy regarding a wastegate control, any thoughts as to a ECM controled gate to work with my turbo? It presently shuts when a vacuum is applied to the servo. Thanks, Bob

[This message has been edited by SATURN5 (edited January 28, 2001).]

 

Thanks Saturn, I recall a previous post from Grumpy stating that (the 749 Syclone/Typhoon ecm) being the most effective solution because it had a 2 bar MAP and was the ecm was capable of interpretting it.

Formula, search on all posts by Grumpy...they are interesting and informative reading. Great insights.

What phase of the conversion are your at?

[This message has been edited by Glenn91L98GTA (edited January 28, 2001).]

 

The 749 is definitely the way to go for forced induction applications. However, I did want to point out that the 730 can be modified to work with a 2 bar map sensor. The problem is - I really don't know too much about it. If you search in the GMECM archives you will run across some of this information. BUT, if you are really interested in this then you'll need to understand how to read assembly language because you will have modify the actual microcode in the 730's program side and set up various 'extra' tables.

Tim

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• Program your own PROMs!. Read my article to get started!
• Research and Experiment before asking questions.
• This is not a chip store. Go to the classifieds if you want someone to sell you a chip or give you a BIN.

TRAXION's 1990 IROC-Z
Best Time = 12.244 @ 112.51mph (1.778 60' / 7.819@88.32mph in the 1/8)
All Natural. No Force. No Drugs. Stock Bottom End. Stock Body Panels.
Gunning for NA 11's with bigger cam, bigger stall, and bigger exhaust.
-=ICON Motorsports=-
Moderator: PROM board at thirdgen.org

 

yep, 749.
For the waste gate just read up on the sysclone/ GN WG solenoid, and it can be sweet. Modermusclecar (closed til 2/1. will be part of rancharges when they reopen) has an item called the Boost Controller that works with the ecm for from the seat boost control. I can turn it down to 15 or to Hi Giggles, while rolling.
When going with the 749 be sure to go thru the Promgrammer stuff at syty.org, and get all the hac info.. Might look up Intech, I think he's used it for some v8s.

syty bin also does things a little different then some of the 3rd gen stuff

GMEPro has a slick editor that as I recall has about everything table/ switch wise.