Gunny Highway

iTrader: (1)

Since I'm currently deployed to Afghanistan, I now have plenty of time to conjure up some way to get 350 HP out of my TBI.

This is the motor I'm going with:

http://www.goautocenter.com/300hp_tpi_1987-89.htm

Now, obviously I'm going with the TBI cam and using Holley 670 cfm TBI. I'm also going to have a custom chip burned while on the dyno for about $350 to get the most out of it.

Now the optional TBI cam specs are slightly smaller than that of JPrevost, but hopefully I can hit the mid 13's with this motor.

Also, I do have the Edelbrock TBI intake, but I'm not sure it's going to be capable of supporting my goals, so should I go with the Holley intake or Edelbrock RPM w/ and adapter?

And lastly, please remember that this is a daily driver, so I want to stay in that same realm of gas mileage.

If hitting 350 HP is not possible w/o screwing with drivability, then it might be time for the TPI swap to begin.

BadBlue91RS

Don't start with that motor. Go for one more performance oriented.

BronYrAur

iTrader: (1)

If it were me I'd keep that TPI cam or go even bigger than that and get either something like an RPM air-gap manifold or a single plane like the weiand 7525.

BMmonteSS

I'm kinda in the ball park that you are looking to go in. I'm guessing I have about 300-315 hp and I'm using a cam that is pretty close to the "TPI" cam specs for that crate motor. As for 350 hp your gonna need to have a motor combo that works very well together. The heads on that motor are going to be the problem. If I were you I would get the HO crate motor long block and add a bigger cam along with a single plane or rpm style intake. (both of which could possibly require a new hood, wiend excelerator fits nicely I hear) I'm pretty sure you can get a 454 tbi to support 350 hp with the big injectors and cranking the fuel pressure up in the neiborhood of 20 psi. That is all going to be in the tune, I hope you trust your chip burner.

Drivability wise you won't have a problem getting the bigger cam to act nice, but fuel milage wise you need to seriously step back and decide what you think is good milage. You will not get the same milage out of a 350 that you got out of your 305. I'm getting around 21 to 22 running 80mph on the highway with the ruffly tuned combo that I have now so that should give you a guestimate of what is possible. Also alot of drivability is in the tune. Your chip burner WILL NOT be able to get you a spot on tune in a hour or two dyno session. You would be way ahead to get the equipment and do it yourself. The dyno will be very helpfull for the WOT stuff only.

Also you don't need 350 hp to run mid 13's. A 300 hp motor with the right drivtrain parts will get you there. Also for anything over 300 hp you will need to spend a crap load of money to get a TPI system to support it, ported plemum, new runners, new TB, possibly a base, ect. All you need for the tbi is a 100 dollar intake a 454 or holley TB and a new fuel pump, which you would have to have with the tpi anyway.

I am by no means the holder of all TBI of info but I do have pretty good idea of what it can do. Hope this helps and thanks for protecting us over there.:yourock:

Dewey316

IMHO the TPI cam is WAY too small i would toss that factory TPI cam on a 305. but for a 350, you should be looking bigger. although the larger cams take a little more work to tune, it is the way you are going to get your power goals. with a carefully matched cam/head/intake combo, it is very easy to make drivable, streetable power with EFI.

someone hit the nail on the head, look at the 350 HO engine, ditch the cam that is in there, and give comp/lunati/whoever a call and get the rigth cam for you application. i personaly suggest giving lunati a call, ask for Harold Brookshire, he will take care of you. again, IMHO, the best way to make power with TBI, is a healthy cam, and a single plane intake.

BMmonteSS also has a great point. it is a waste to pay someone to tune your car for 3 hours, most of us have probably 100's of hours into tuning our cars, it takes alot of time to really get the tune nailed. get the stuff, learn to do it yourself. get the part throttle stuff done, then get on the dyno, with a WB, and get the WOT tuned. it is not a hard process, but it is time consuming. in the end it will all be well worth it, as you will have the power you want, descent gas milage, and a very drivable, well behaved engine.

BMmonteSS

right on dewey.

Just for clarification when I said TPI cam in my above post I was refering to the cam that came in the TPI version of that crate motor which is a good bit bigger than a stock TPI cam ever wanted to be.

Ohh yeah almost forgot. A real poplular combo is the HO crate motor with the LT4 hot cam. Makes a real big fat power band and peaks near or above 400 hp when everything is tuned right. That cam is pretty healthy to tune for your first time though.

Dewey316

luckily the hotcam is not on a 110 or 112 LSA, having the wide seperation, does make it tunable for a first timer. i think the HO/hotcam combo would be the ticket. might max out a 2bbl TBI though, i don't think it will max out air flow, but fueling that beast might get hairy.

steve8586iroc

Dewey, I thought the LT4 hot cam had a 112 LSA. I am also hoping to put my 350 Vortec headed (pocket ported) RPM Air Gapped LT4 Hot Cammed 454 tbi'ed Headman Heddered engine in my 91RS Camaro this summer, if things go according to plan. It should be a small improvement over stock.

Steve

Gunny Highway

iTrader: (1)

I was under the impression that the TBI didn't like anymore LSA than 114?? Is that bad gouge?

va454ss

iTrader: (1)

I use 110 LSA with TBI, but that's with a BB.

Make it easy on yourself and get a 383, vs the 350.

If you're using TBI, build for torque.

BMmonteSS

Just for a reference my car idles slightly higher in the map range than stock and definetly has an audible lope. It really wasn't that hard to tune around. Most stock vehicles idle in the low 40's, my car idled in the mid 40's with the carb on there and it's in the high 40's with the tbi so I should be able to get it a little better yet. cam specs below.

Comp Extreme Energy 4X4

218 .462

226 .480

111 LS

It's not that TBI's don't like less LS it just makes your map reading at idle a little muddy. A stock motor has almost rock steady map reading while mine wanders around about 3-5 map. Just have to tune around it. Traxion is running a multi-port SD system which tunes alot like TBI with a cam so big he idles in the 70 range, no problems there.

Dewey316

yes, i just checked it, i could have sworn it was on a 114, but i guess not

Monte, yes i have been watching traxions posts closely with his very large cam, i am really suprised he is getting it tuned.

and for reference....

My cam (haven't gotten it in yet, or tuned) for the 305.

274/284
210/218
.492 .492
112

BMmonteSS

I think the trick with big cams is just ignoring or at least partially disabling the O2 when idleing. You get alot of fresh intake charge out the exhaust whith a big cam and thats what throws the ecm into fits. Just give it what it needs and it'll idle just like a carb. You just have to feel around blind to see what it likes, thats where a WB O2 comes in handy.

RBob

iTrader: (1)

I run the engine in closed loop idle and open loop off idle. To get a good idle just takes a few tricks on getting the ECM to behave. Then using the nose to get the AFR dialed in. If the exhaust stinks then it is too rich. As you lean it out the smell goes away. Need to make sure that there is enough SA for a decent idle. Having 24 to 28 deg is not unusual.

Getting the ECM to behave takes a few cal changes. First is to reduce the proportional gains to almost nothing. Don't need the ECM changing the PW so much that the engine gets erratic.

Find the cal term for idle O2 error reduction and set this back to no reduction (255). Tighten up the O2 error window for idle. Then to get the idle to pass the smell test use the idle O2 window terms along with the low airflow terms to set the AFR. Once all setup, change the VE table to get the idle BLM/INT closer to 128's.

Change the idle control SA tables to match the changed MAP at idle. May need to reduce the magnitude of idle correction SA. Note that the '747 does not have idle SA control, the '8746 does.

Having a small amount of heat in the manifold will also help. This can be in the form of small holes to allow some exhaust heat through the riser, to plumbing coolant through the manifold heat riser.

All-in-all it is surprising how well an TBI'd engine can idle at 62 Kpa MAP and 850 RPM with a 108 LDA cam.

RBob.

Berlinetta

Man, that is the sweetest poetry I've ever heard.

Guys, Im not quite sure why some of you are anti-chip tuners. I know its a lot of money but they have a hell of a lot of experience doing it, if you pick the right place, and I would think that they wouldn't need a whole lot of time to tune your car considering their experience. I e-mailed fastchip and they give you half a day, which i think is 4-5 hours. They do GM exlusively.

Just my two cents. Id like to hear your thoughts.

Hey guys, what about the 383 vortec headed stroker on the website gunny gave? 340 HP and 435 ft/lbs of torque. You can't beat that anyway you slice it. And look at the cam profile! All that power with that puny-a!@ little cam. I know it costs money, but my ***. Feel the Power!

Dewey316

i have personal experiance with ed wright chips, other mail-order chip makers (i will leave un-named), and trust me, they just can't compare to doing it yourself. i can send you a 'custom' ed wright bin for a 350/mini-ram/hotcam TPI combo, and then i will send you the stocker. you can look at it, then tell me why it was worth the $350 it cost. point is he changed almost nothing. the car ran ok, but needed alot of work, the pump shot was no where near correct, cruise was descent, WOT was way off, basicly over the phone, even an expert like ed was not able to accuratly GUESS (which is what these people are doing) what the engine needed. not matter how many datalogs you send, they aren't there, they don't drive it, they do pull the plugs to look at them, there is so much more needed to get the correct tune, then looking at the logs and making a couple of minor changes. also not that the above experiance was on a MAF car, had it been a speed density car, like a TBI, the tune would have been every harder to dial-in, and i am sure the chips sent would have been much worse.

Berlinetta

I live in North Texas. Ed Wright is in tulsa. It wouldn't be stretch for me to drive up there. Think they could do a better job in person?

Dewey316

in person probably, but reality is even for an expert it takes more than 4-5 hours to properly tune. you just can't get the data and testing you need in that time, you can get WOT done, on a dyno with a wideband, but part throttle, and all the little stuff like the timing curve, ect take alot of time, trial, and error.

BMmonteSS

You won't fully realize the power of doing it yourself untill you get your bin opened up and take a look at what you can change. Once you do a data log or two and try to get your VE table squared away you quickly realize that it takes a min of 5 chips to get it close...not perfect but close. There is just no way some one no matter how good they are is going to be able to guess at what VE curve your motor needs on the first try or even in 3 tries. Thats just your VE curves let alone your timing, idle, and cold start stuff. It just sounds crazy to have to mail it back and get a retune every so often. On a car that is in good running condition with very few mods you could help it out in 5-10 chips. Once you get farthur away from stock you'll have much more time involved in getting it righ.

Call up holley and ask them what jet you need for your particular engine combo. They'll tell you a good starting point but they won't be able to tell you exactly which one will make the best power, they'll tell you you'll have to try a couple and see what gives you the best results.

He would definetly be able to do a better job in person, I'd be interested to see how many reburns he'll do till he calls it good enough.

Add it all up the cost of having him do it is comparable to doing it yourself.

Berlinetta

thanks. I have a couple of years to gather all the info ill need for my car. i have to wait until i get out of college but it will be worth it. I got tired of nickel and diming the car. So, when it died, I parked it and decided to wait for the day when I had the time and money to build it right. What about that 383?

You guys are far more adventerous when it comes to tuning than I am :hail: :hail: :hail:

Gunny Highway

iTrader: (1)

I'm pretty sure when Rich92RS350 (using the same engine) dyno'd his with the TBI option and a Holley TBI, he put up 300 HP. Now, if I use that motor with the Holley TBI, Performer RPM manifold, some 1.6 RR's and chip burning/tuning while on the dyno, I should be good close.

Does anybody know if the Performer RPM manifold will fit under a stock hood?

What does 300 HP and 375 lb/ft equate to in the 1/4 mile? (with my 3.23 gears and stock torque converter)

brodyscamaro

Prolly mid 13s

gen3z

i have the hot cam in my tbi 350,it is on a 112*,and the rpm will fit under stock hood with a drop base air cleaner,watch the stud clearence you will need to trim the stud a bit..

JPrevost

The Performer RPM will fit under the stock hood with some modification. Obviously it'll fit better if you use an adaptor plate thinner than the Holley but in this case I used Holley's huge 1"er. Cut the underbracing out and use a drop base air cleaner WITHOUT the spacer. You will have to hammer clearance for the IAC and TPS but the throttle will clear! There are 2 indents on the drop base. One of those indents needs to be directly above the throttle or it will stick. Use a ball end hammer and some wood to massage the base into submission .

miacamaro305

put some better flowing bolt ons and nitrous and u there

BronYrAur

iTrader: (1)

boo, nitrous isn't the solution.

Gunny Highway

iTrader: (1)

I'm probably not going to use any nitrous guys. I don't go to the track and and it's illegal in GA anyways.

Now, better bolt ons?? How do ya mean? Better heads? They do offer Edelbrock heads as option, but there's nothing on there that gives a HP increase number, and at $1,000 for heads and install, I find it hard to believe that the heads are worth $1,000.

JPrevost: Now I'm not into "modification" necessary bolt ons. Is there a lower profile intake manifold out that will give me more HP than the Edelbrock TBI, but still offer all the EGR stuff I need w/o "modifcations?"

Thanks for all the replies guys. Even though I'm on here sporadically now, it's a nice taste of my stateside routine while here in Afghanistan.

Gunny Highway

iTrader: (1)

OK, I'm bringing this back to the top, because I got an email from the company today about the optioned heads.

For roughly about $850 more (which will make the price $3,200 shipped to my door), I can get the optioned aluminum heads. Now, apparently these guys aren't aware that their TBI optioned motor is putting up bigger numbers than they say.

The guy stated that with the TBI option on this motor, it would put out somewhere around 250 HP and with the optional aluminum heads you can add around 20 - 25 HP.

Now, when Rich92RS350 dynoed this motor with the TBI option, Turbo City TBI, Edelbrock TBI and an Ed Wright chip, he came out with 317 HP and 399 ft/lbs at the flywheel .

So if I go with either the Edelbrock Performer Centerbolts or the Trick Flow 23*'s and add some 1.6 roller rockers, I'm thinking I can pick up about 20 HP w/ the heads and 8 HP with the 1.6 RR's which will put me at 345 HP and some number higher torque, which I'll be COMPLETELY happy with.

Now questions:

Do you think the extra $800 is worth it for the heads?

If so, which heads would you choose? I'm leaning towards the Trick Flows personally, although I don't know much about either besides the fact that they're smog friendly. I looked at the sheets on them, but I can't decifer all of those flow numbers and cc's and what not.

Do you see any problems w/ pushrods or what not by adding the 1.6 RR's?