|10-24-2016 08:32 AM|
If you're really interested in the tuning aspect of DIY,you may wanna watch the classifieds over at thirdgen.org.They frequently have this stuff for sale over there at good prices,as a lot of them are either going LS,or,carb.
There's also a lot of tuning tips,& help over there as well for the TBI/OBD1 stuff,along with a few guys that offer tuning..
|10-23-2016 06:14 PM|
Chip burning can be pretty time consuming.The better way if you are gonna be doing alot of tweaking is to something like the Dynamic EFI.You can tune thru your laptop & make changes without having to burn new chip with every change.
This site has some good info for tuning, fueling, etc for the GM TBI systems.
|10-23-2016 05:59 PM|
The pre 93 ecm is extremely slow.The 93 up are 8 to 10 x's faster & more capable.With the addition of the 4L60E, GM had to use something better.They still leave alot to be desired tho.
The mail order is hit or miss.My experience with TBI Chips & Bryan Harris was based on obtaining a tune for that larger 213/219 Lunati cam I mentioned earlier.After 4 failed attempts at getting it correct my then brother-in-law decided to start burning his own.Prior to the chips from TBI Chips, he was using an off the shelf Hyper Tech chip.When he read the tune from & the chip from the $125 HyperTech & compared it to the $250 tuned chip from TBI Chips, it was virtually identical.After a slight learning curve, he had the truck running great with no codes.
|10-23-2016 05:41 PM|
may want to look here for more info on tuning differences/how to tune.
GearHead EFI Forums
IMHO it is better to learn how to DIY tune than to send off for a mail order type tune (seen a few mail order tunes that looked like crap on the datalogger) but the learning curve is steep and it may not be cost effective for your goals.
I have no experience with the tbi setups but am learning on a '95 LT1 B body. Told myself that I was just gonna calibrate for the new gears and done but it seems I am constantly tweaking things because I can, like a kid with a new toy....
|10-23-2016 04:31 PM|
The "tuning" aspects of TBI have me fascinated... these vintage computers must be sloooow. Before I would buy an aftermarket chip I would want to know the exact difference between stock oem and the new chip.
timing? how much do I have now vs. the new chip?
fuel? if the vehicle is reading tps, map and O2S how is the change made?
I would like to see a side by side chart/graph of both chips as a starting point.
I have not looked into what is available in the world of chip programming at all.
My check engine light came on just once when it was just under 5 years old, 70,000 miles. A new tps switch fixed it.
GM OBD1, nothing I have spent much time with..... yet!
|10-23-2016 03:45 PM|
|jokerZ71||Meant to mention this earlier, but, let it slip my mind.When you do your upgrades & get to the fueling aspect, (increasing fuel to support the upgrades), don't be tempted to buy & use the 18 psi spring that Mr Harris suggests & sells.This very seldom works.Especially with milder upgrades you are considering. You need to be able to fine tune the psi to your combo.18 psi is not likely to be needed for your setup & will give you headaches upon headaches in the idling & low rpm operation.You're gonna be somewhere in the 13 to 15 psi range based on my experience.|
|10-23-2016 03:24 PM|
Not gonna turn this thread into an argument with you over your BS & false claims, as it has nothing to do with the OP's goals, or, what he's trying to accomplish.Just longwinded junk that doesn't say very much.
In a well planned LT1 on a dyno with no accessories & open headers, the LT1 cam just barely broke the 350 HP mark.The LT4 HOT cam just broke 420 HP.Even with heavily ported aftermarket heads & a 226* cam,471 HP.
|10-23-2016 03:00 PM|
|jokerZ71||The LT4 Hot cam will not under any circumstances take a 350 motor to even close to 500 HP. Not N/A anyway.It's just nowhere near enough cam.Even 425/430 would be a far stretch.It takes an optimum setup with 10:1 or better & a very well tuned exhaust to break the 400 mark.The LT1 stock cam is not gonna touch 400 HP.Maybe 350.Maybe.These cams are just too small to make these #'s.The LT1 cam has less than 210* intake duration. The Hot cam is less than 220*.They are both lazylong ramped cams to boot.If what you are saying is possible, why do you regularly advise ppl everyday to use these big 240 to 250 duration cams & claim 500 HP. It takes alot of cam to get a 350 into the 500 HP range.IDK.Maybe you think that Vette emblem adds another 75 to 100 HP.|
|10-23-2016 12:13 PM|
WOW!!! Almost 500 HP from the LT4 HOT cam ??? Maybe with a 100 shot. .LMAO.That's a 400 HP cam & even then an almost perfect setup.That's another story tho & beside the point.Just thought it was really funny.
The new Vortec motor would be a good choice but not what you're looking for at this time & budget would be over $2500 by the time you get it installed & running.You can do the cam swap & convert to the roller cam, if your block is ready for approx $600 & that includes a new chip.You can hit 250 to 275 HP & increase torque across the rpm range to close to 350 to 400 ft/lb relatively easy with your current motor.Just have to match it all up.Should pull that 2500# boat really well with your 3:73's.
|10-23-2016 08:27 AM|
The cam degree calculator I mentioned earlier also gives the overlap based on the info entered.
Alot of the GM cams can be hard to figure, GM rarely provides the true ICL of their cams & alot of the published durations are listed in true actual seat to seat vs @ .004, .006, etc.
Keeping the TBI computer happy means retaining as much vacum as you can & small overlap.
|10-23-2016 07:56 AM|
Yep, pulling the intake 1st would be a good idea.The bosses will be there.They may just need to be drilled/tapped.You want to make sure the top lifter bore surface is machined flat also for the dog bones.
Do you know which block casting you have? The #880 Vortec block was used pretty widely in 95 on some of these motors & i've never seen a #880 block that wasn't roller ready.The #638 block could be either way & anywhere in between.GM Performance also sells a kit that incudes everything except the cam & timing set, including new lifters for about $275.A couple of other places, have their own kits as well, including Summit, but, I have no experience with those.
|10-23-2016 07:37 AM|
My original post was just to give me some cam options if the engine block is not roller ready.
I think the stock 96-99 GM roller vortec cam would be great for my use.
Best practice dictates I take the intake off before ordering any parts just to check if it's ready for the roller lifter spider or not.
I found some interesting reading on a corvette forum about GM cams, those guys are all about tweaking using all the stock GM exterior components... Not just installing aftermarket manifolds/headers/heads/carbs to get H.P. improvements.
Reminds me of the kinds of mods we did for motorcycle production road racing.
|10-23-2016 07:17 AM|
Both of the Lunati cams I listed are in the list from TBI Chips above, along with the Elgin cam you were considering. The duration of any of these cams is not gonna take away any noticeable low rpm torque.I do strongly advise you to invest in a tune tho to bring it all together. However, from my experience, I wouldn't use Bryan Harris from TBI Chips.It would be better if possible to get the chip done locally.Mr. Harris does pretty good on tunes in person, but, the mail order can be hit, or, miss & may require several chips before nailing it down without a data file to work with.
I would also urge you to convert over to the roller cam.You can usually grab the parts needed at a JY for less than $50, or, even sometimes on Ebay.Even picking up the hardware & stock Vortec roller cam would make some decent gains & be relatively cheap.The stock Vortec cam does good with 1.6 rockers also.You would then already be roller ready if & when you do go 383.Just about anything tho will work better than that broomstick stock cam.
|10-22-2016 10:07 PM|
|footnbruce||It has a rebuilt 4L60E, 3.73 gears...k&n filter, 3" cat, 3" cat back system... A heated o2 sensor and A new better flowing 48 state flowmaster combination collector/ cat will be installed in the spring. Timing is bumped 4 degrees.... the roof needs paint, GM Olympic white peeling problem that has been fixed in a few places over the years.|
|10-22-2016 07:40 PM|
|jokerZ71||You can make some decent gains in your motor.Any of the cams you listed would makes improvement. Some more than others.The L05 & swirl port heads are not a bad combo for what they were designed for & for the use you state, fit the situation.You don't need a bigger high performance head & you definitely don't want to start porting on the swirl ports.The design of the ports & the swirl inducing vane is what makes them work & provide the lowend torque that they do.They actually make slightly more torque than Vortecs up to about 3000 rpm & from there the Vortecs leave them in the dust.Like I said & you already know, the stock cam is very weak & the stock tune leaves alot to be desired.Any of the cams listed above will work much better with other upgrades to support it.Good free flowing exhaust.Proper fuel psi & a reprogrammed chip.That Elgin cam or the smaller Lunati wouldn't have to have a new tune, but, it would make a world of difference in performance after the upgrades.What transmission & rear gears do you have?|
|This thread has more than 15 replies. Click here to review the whole thread.|