tokabi

i have finally decided that i want to beef up my 91 rs w/lo3. one of my more radical ideas is to figure out how a supercharger would work with a high flow tbi from holley. just hoping to get some input. thanks.

CamaroGuy71

try nitrous...cheaper...more bang for the buck. a guy in the mfba supercharged his car and it didnt really get him anywhere... goes by schumacher on the mfba website. he told me its not the mods u have, its how well what u have works together

Tas

weiand roots blower with a carb to TBI adapter plate($12) from holley should work fine. Probably need a 4" cowl hood though.

Blown 305 TBI

I'm Schumacher from the MFBA, and that is my blown 305 TBI. Although I'm happy with the results I've gotten so far from my setup, I still wouldn't recommend going this route.

First of all, the kit I purchased from Paxton isn't even available anymore. I paid almost $2500 for the kit back in '99, and on my 100% stock car it got me from 16.3's @ 84mph with a 2.5 60' to 15.7's @ 88mph with a 2.3 60'.

I didn't run the car at all last year due to minor transmission problems that I didn't want to make worse, but in 2000 I got a best time of 14.42 @ 95.96 with a 1.98 60'.

This time was made possible by adding Edelbrock TES headers, no cat, 2 1/2" Flowmaster cat-back, Accel cap, rotor and coil, Taylor wires, AC Delco plugs 2 heat ranges cooler than stock, Ultimate TBI mods, @ 7psi of boost (max boost) fuel pressure is at 17psi, Spohn LCA's with relocation brackets, SLP take-off posi with GM 3.42 gears, and Nitto 245/50/16 Drag Radials.

In my opinion nitrous is a much better choice for TBI.

But I will find out what a supercharged 355 TBI can do next year.

HrdRockA4305

I wish I could find that TBI cap thing somewhere as a seperate part. Would be good for piping a cold air setup.

racereno

Good source for ram air parts/kits:

http://www.ramairbox.com/

v8powr

Yeah but just think..you dropped off almost 2 seconds off your ET by just letting that LO3 exhale and a few traction mods. Just think how much would faster it would be if you got the real problems fixed...like heads and cam and the intake! I imagine you would knock off another 2seconds with that and a few more traction mods and low 12's shouldnt be all that hard to obtain. Just my opinion but from what ive read...low low 12's are obtainable and not all that unrealistic for the lo3.

HrdRockA4305

IMO - blowing more air into a TBI motor isn't a good thing to do. Until the super restrictive cam, heads, intake, and exhaust are gone, you're gonna find a wall and hit it hard when it comes to power. I woulda spent the 2-3 grand the blower cost on those things I just mentioned... you'd have been going faster.

Don't take that the wrong way, I sound like an *** when I say that but thats not what I was trying for. Just being realistic.

nsimmons

talk to joby, his crossfire made 150hp more with a bone stock engine, by what experience do you base your statement?

Blown 305 TBI

v8powr, that's exactly how I think of it. I never said I was disappointed with what I've done, I just don't recommend it. My plan was to do the exact same things that you suggested, but I came across an 89 350 block from an IROC (minus heads and intake) for $150. So now I'm in the process of building a 355 that should make around 300-320 RWHP N/A, then adding the Paxton to that. But I have a feeling that I'm going to find out the true limits of TBI this way. Then I'll probably go to a stealth ram.

HrdRock, I totally agree with you. I do believe I've hit that wall with my stock engine. The only thing I'm going to do to this 305 is an LT1 cam (that I've had laying around for a while) and the vAFPR. Doing these 2 mods, along with my new trans and 2800 stall, I should be in the 13.8 range. THen next year the 355 will be done.

TBI305Camaro

will the roots style blower from holley work with serpentine setups? we are talking about the 1700$ one right? i know they make one that around 3k for TBI

dimented24x7

iTrader: (2)

the true limit for a tbi is when the air flowing through reaches sonic speeds. After that, the air wont go any faster and the only other option is to make the intake charge denser (i think more mass goes through if its denser)

v8powr

yeah blown....im one of those hard headed a holes thats gonna squeeze every last drop outta my Lo3....for restorative purposes. i wanna retain the stock engine and maybe stock style t5. but if i can get that lo3 to around 325 rwhp n/a ill be pleased....if i can build it to hold 12lbs boost and get it to around 425 rwhp...ill be estatic. im just takin my time but in a few years...im definatly gonna try to shock some people.....i can see my tag switchin from v8powr.....to 30what!! LOL

HrdRockA4305

I was very impressed with his car, especially how he did like almost everything himself. The reasoning behind my opinions is that you can keep throwing more and more boost at a stock TBI engine, but to really start making power you're going to have to actually tear into the motor itself and open it up. Plus the fact that the stock fuel system is only good to about 260 HP or so.

As far as backing this up with experience, I can't. I'm just going on everything I've been reading here for the past year pretty much.

tokabi

i was thinking about getting a fastburn 385 adding a holley procharger 144 and topping it with a holley 900 cfm four barrel tbi with the commander 950 ecm. any opinions?

nsimmons

hardrock..i think maybe my response was a little snippy..sorry about that.

Anyway back to jonas, he just finished a new build up with afr heads and a nice cam..with the blower he ran a 3.9 and 4.0 sec 0-60 and low 12's He still hasnt touched the tbi's or installed his offy crossram.

HrdRockA4305

Hey don't worry about it, I don't get offended easily. And I don't mind being called out about not being able to back up most stuff I say, cause its true.

And about Jonas's car, thats freakin awsome, I'm gonna try n find his website and check out the latest if its posted.

JoBy

It is G-Tech times, but they should be worth something.



Still stock non-ported intake and stock TBI's.

Mods:
No emissions stuff.
AFR 190 Heads.
mild blower cam and hydraulic lifters.
Roller tip rockers.
Hooker super competition headers and home built dual exhaust with x-pipe.
Supercharger and misc mods to make it work.
Dana 44 rear end with 3.45.



The 1/4 mile times are with street tires on a road that could have better traction.
I found another place with better traction, but the stretch is only long enough for 0-60 mph times.
I think my starting skills are improving too.

prevous times:

1999-07-29 ( Before supercharger )
0-60 5.94
0-60 6.00
0-60 6.26
0-60 6.27
0-60 5.92
0-60 5.72


2001-06-31 ( With supercharger on stock engine)

402 12.73 116.3
402 12.76 114.1
402 12.89 113.9
0-60 4.75

New times after the rebuild:

2002-05-21 ( Without supercharger )
402 14.46 97.7
402 14.46 98.1
402 14.53 97.8
0-60 5.66
0-60 5.54
0-60 5.48
0-60 5.59
0-60 5.51

2002-05-21 ( With supercharger )
402 12.95 115.0
402 12.97 116.5

2002-05-24 ( With supercharger )
402 13.35 116.4 ( Major burnout thru first and second )
402 12.62 116.9
0-60 4.27
0-60 4.04
0-60 4.36
0-60 4.20

2002-05-25 ( With supercharger )
0-60 3.91
0-60 4.07

BillD91RS

JoBy How hard was it to get the dana 44 rear into your car?

JoBy

It was almost a bolt-on.
I only had to modify the C-beam ( drill four holes ).

More info here:
http://w1.601.telia.com/~u60113744/diff/diff.htm

Jza

Let's all wish Jonas a happy birthday! woohoo!

83 Crossfire TA

iTrader: (2)

Yea, but I've opened TB bores out to 54mm using a fixture I built and my drill press, which is big enough for 90% of what people are looking for...

JoBy, do you still hang out at the crossfire vault? I popped back a few months after the server was rebuilt but it seemed dead and I never went back to check...

palric

iTrader: (1)

I would want to optimize my N/A setup first. The L03 is low output and the manifold and cam would make any blower look bad.

Upgrade to a Holley 670 TBI adapt it to an after market performance carb manifold, put a decent cam in it and fix the exhaust -- then put on a blower.

The stock L03 setup is like trying to breath through a straw.

have a nice day,
RP.

83 Crossfire TA

iTrader: (2)

Yep, perfect plan... Spend your $$$ on a TB that's smaller (roughly 48mm bores if I remember right) then what the stock one could be easily opened up to and then stick it on a 4 barrel intake that will either not match the rest of the setup (a single plane) or one that you'll never get good fuel distriblution with (dual plane with the adaptor).

If you want a kickass, fairly cheap street TBI setup, bore the stock TB, get a set of vortech heads and a TBI/vortech intake from gmpp, slap a set of headers on it and be happy. If you're going to run a blower you can skip most of that and just open up the stock heads or use a set of cleaned up, 'normal' SBC heads (off of a TPI or an older engine).

The biggest restriction on those engines are the heads, cam and exhaust and you'll get a lot out of just tinkering with them.

palric

iTrader: (1)

Whoa slow down 83 Crossfire TA .

The Holley 670 TBI bores are 2 inch diameter and the factory TBI is 1 7/8 max (from the 454 in 90-92 only). The factory injectors are what -- 40-50 pounders ? The Holley OEM 670 CFM TBI is 70-80 pounders your choice. They flow far better, work far better and make far more power all by themselves.

Have you done the Holley TBI to carb manifold setup I described ? I HAVE (Weiand 7525) with the Holley TBI with the right cam with the right exhaust and kicked *** with my L03 5-speed Formula all over town. I could have gone to a blower but didn't becuase my mod'ed setup worked so well.

If you want to go to Vortec thats your business all I am saying is there are some simple alternatives to be had relatively inexpensively that are known to work without going down the Vortec cul-de-sac.

have a nice day,
RP.

83 Crossfire TA

iTrader: (2)

Have I specifically installed a Holley 670? No, of course not. Have I tinkered enough with various TBI systems to know what works and doesn't... Yes (ranging from single injector 4 cylinder GM, dual injector 2barrel GM, Crossfire, even a 12 second car using a custom built setup using 2x 2 barrel ford 5.0 HO engine TBI's ('84 setup)).

My point was simple, you're wasting money where you don't have to.

What do you gain from the Holley? More air flow? No, the stock TB can be bored larger then the Holley setup for cheaper. If you were to bore both I really doubt that the holley could be bored larger then the stock TB, the bores on both are at the same spacing which is pretty much what limits the size (and you'd still end up paying for the Holley). If you don't have the skills/creativity to do it yourslef (I did a few using a home made jig), a machine shop could do it cheaply, and you could order just about any size throttle plates from Barry Grant (throttle plates are not round), again, I made a jig to cut them using a dremel and a sanding disk.

Injector capacity? Off the top of my head, just with the GM V8 TB setups you have:
- 55lb/hour (stock 305)
- 61 (350 trucks)
- 62/63 (305 crossfire)
- 67/68 (350 crossfire)
- 74 (454)

BTW, the 74's will work fine to at least 15psi where they would flow about 96lb/hour, I've seen them used in a blow through turbo setup up to 23psi...

Is the holley FPR adjustable? The stock GM one could be made so by just punching out the cap on the bottom of the can (5 minutes, tops).

So, where do you gain?

And like I already said, most near stock TBI setups are not restricted by the TBI. You'd have to upgrade the exhaust, heads, intake before messing with the TB would help that much.

palric

iTrader: (1)

The Holley bolted on out of the box it hooked up and the car started right away. It made the power they claimed and more after I started including more serious mods. I drove it ('88 Formula) with this unit for about 30,000kms with no problems. More reliable than my current TPI has proven to be -- by a country mile. Enough said.

RP.

83 Crossfire TA

iTrader: (2)

Well, I'll definitly agree with that, TBI works well and has much less to go wrong then TPI...

B4Ctom1

TBI experts like Bill Howell, and Turbo city say that at higher HP levels cylinder fuel distribution gets to be a problem. I wonder if force feeding remedys this or makes it worse (only 8 o2 sensors or 8 EGT's could say for sure)

Drac0nic

All right, dumb Q of the moment; what motor were these on, what mods were on the motor and how much HP did they support boosted? Wanting to do a 4.3L V6 eventually, fuel system is next on the list, Megasquirt's done and going back in soon. Any idea on if they'll idle well with that setup?

senatorcbp

HEY I have a 305 TBI and you can make it fast. But I just wanted to say something. Lots of people on here say the restrictions or weak areas on our LO3's are cam, heads, and exhaust. Well, what else is there to make power except induction. Heads, cam, exhaust. The rest of the engine itself doe not contribute to making power. Lets face it these motors in stock form are weak. So the best way to start to make power is replace all of these parts first then worry about external power adders

rmmstnr

$12? the closest thing I can find to that is the "2bbl adapter TBI (spread bore to TBI flange)" (510-17-4 at Jegs). this costs $46, and I'm still not sure if it could mount the Projection unit to a Weiand blower. if you or anybody could, please elaborate on this. I've got different plans, but they still involve getting a Holley 670cfm TBI on a Weiand blower.

sleepybu

the holley adapter 17-41 and or 17-45 should work for you...however at 46 to 54$ i'd get the gaskets and a 1/2" thick pice of alumnum and start drilling






ps: i asume this is on a 142 SC

vorgath

I'm going to try to put an Eaton M62 on, to work with the TBI.

If I would have a TIG welder, seriously, piece a cake, but since I don't have one uhmmmm

JoBy

Fast355

iTrader: (2)

Nice engine Jonas

What is it in?

I had a Weiand 142 on my G20 Vans 350 for some time. Ran very strong. With the stock heads and cam it didn't make but about 350 HP, but regardless the torque was much greater.

83 Crossfire TA

iTrader: (2)

That looks like a wipple or a KB setup.

Vorgath, I don’t know what you’re planning on putting an M62 on, but it’s a fairly small blower, probably appropriate for a V6 or even a 4, but not for a V8, if that’s what you’re doing, but that’s not your biggest problem, they will not tolerate fuel going through the housing, you’ll wipe out the bearings and mess up the rotors (a buddy of mine is an engineer for Eaton, talked to him about it before, the other thing that he brought up is that they are machined to work with the rotors hot, as the rotors get hotter the blower gets more efficient, cooling the rotors with fuel would be counter productive, unless possibly if you started with a new set with the ablative coating, but I’m not sure what gas does to that).

‘bu and Taz… you live in your own little world where aluminum grows on trees, right? yes, I’ve been known to waste my time building all sorts of cool little **** like that for no good reason, but usually it starts with “noone quite makes that” + I have some scrap sitting around that would work for it. That Holley adaptor runs about $40, while a TB gasket will run about $7, and the aluminum you’ll basically end up paying $20-30 for a chunk that’s big enough to make it out of (the cheapest place that I’ve found you can do about half that but they have a $3x minimum order, so I paid over $30 anyway). By the time you get what you need to build this you’ll have spent most of the $40 to buy an adaptor plate.

vorgath

JoBy,

what kind of supercharger is that ?




83 Crossfire TA,

well I'll give it a shot, if it won't work, I can always sell it on Ebay, or take the 63 dollar loss, which is how much it cost me at the junkyard.

JoBy

The pictures are from a swedish build.

http://www.usabil.nu/reportage/kompressor.asp

It is s Chevy 350 and an Autorotor (Lysholm, Opcon, whipple) supercharger.

vorgath

*reads it*