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I think the 76mm will get you closer to the 9's than a 70mm but depending on the car weight, I guess some mustang boys have pushed T70's into the high 9's before so it may be possible. Figuring you need upwards of 600whp, thats asking for a good bit out of a T70. I've seen a DSM make 710whp on racegas with a single T70 but he's operating in a different area of the map compared to a 305 would be, so he can get more lbs/min out of it.

 

The typical f-body will need more like 725-750hp to get into the 9's, unless the car is _really_ light. OTOH, a mismatched combination with a turbo that can push _something_ into the 9's won't be as fast as a well matched combination that may be borderline for getting there if you know what I mean.

My choice on those would depend on pricing and what hot sides are available.

 

If you feel the rear will hold up to a transbrake launch you can touch 9's with less power...else if you come off the line slowly, you will need a crapton of power up top to make up the lost time. ask me how i know

Most of your ET is in the first 330 feet

 

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what cam is that? That's way too much gear...

huh... OK, for a 305 my instinct is something in the .85-.95A/R range, so it looks like you're a little small or a little big with either of your choices. I'd shoot a little small if you're looking for better street manners, and little big if you're looking for best performance at the track, of course, I'm cheap, if I'm debating between $275 and $875 for the same use it's goig to be the $275 and it would be the 1.05A/R setup.

 

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I'm wondering if you need a q-trim... a T4 .96 P trim may work but start to become a restriction above 600whp I'm thinking. P trim T70 is like 600 bucks, so I'd think the T76 should be around the same price. Look up Modular Turbo, a vendor on LS1tech. He got me decent deals on my masterpowers.

 

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the gt45 will be spooled up by 3k on a 305,but regardless if ur using a megasquirt u can spool that turbo at dead idle if u wanted to
http://www.youtube.com/watch?v=YpZFg_2_5xo

if u want twins i can build u a set of log headers i already have the weld els
and a pair of ebay t3/t4s will support just a tad over 900 hp

 

project89- really stupid question... whats up with the popping sound in the video??

 

the popping u hear is the antilag/lauch control system active

when activated it adds between 5-30% extra fuel depending on how u configure it

at the same time it retards timming i use a setting of 0* btdc ,and it also starts droping spark to one cyl at a time

this allows the raw fuel to get into the turbo headers were it is ignited by the retared timming and spins the turbo up really fast

fuel amount
ignition retard
rpm
and spark cut (number of sparks droped per amount of ignition events and even the park drop pattern )

is all adjustable

 

pretty cool... do you have a catalytic converter on the car?? I'm wondering if you have to worry about raw gas clogging the cat or if the raw gas is "recycled" back into the engine...

Yeah.. as you can see my knowledge of turbos only goes so far..

Dan

 

that was pilsburys car, i helped him build it and did all the base tunning on it.

i dont rember if he had a cat on the car

i dont recomend using one though unless u have an open cutout before the cat,also this system has to be used with a stright threw muffler
or u risk loading the muffler up with raw fuel and exploding the muffler

for cars with cats and chambered stle mufflers id setup the launch control as a 2 step

no extra fuel added with ignition retard with spark cut only at the very upper limit of launch rpm

 

Thats interesting, i dont know if they raised prices or not, but 650 for T70 seems high let alone 775 for T76. I got my pair for 550 each from him

 

I thought you had a pair of TE44s? That should easily be enough to push a third gen into the 9s. Why not use those especially if you're doing custom uh oh
headers. Otherwise single wise I'd be thinking T76. I like the idea of the HX52 as well, I'm going with a TMF5502 on mine (I think, unless I figure out where to cram two GN turbos in my engine bay)

 

The HX52 would be my no brainer answer if it wasn't for the fact that there is no real upgrade path from it. That is the largest compressor connected to that exhaust flange, everything else is different. TMF5502... never seen one in person but they were used on some of the same DD's as the GTA4202 that I have... a bit largish for a single on a 305 and may be a pain to package.

The problem i have with twins is that there is no way to run more than a 2.5" down pipe on the driver's side unless you rearrange the brake setup (manual or maybe hydroboost). If you want to go twins there are tons of choices that will get you close or into the 9's that should be fun...

 

I'd just get a hydroboost. I'm going to probably hit one up in the future no matter what I do.

Yeah it's a similar package to a GTA4202, and it's being a bastard to cram in. Some mods to the floor pan and it will be servicable. I'm thinking of getting a scavenge pump and mid mounting atm. Since I have a van under the passenger side seat would be nice and easy, improve weight distribution, remove engine compartment heat and probably some other stuff I have forgotten. Maybe I should get an engine out and start mocking a bracket up for this beast.

It's a "bit" large but based on my calculations assuming I'm putting down 250-275hp N/A it will actually fit on the map of a similar sized turbo (GT4202/4294) fairly well. The turbine/spooling is my big concern, but I figure I will use electronics for that if worse comes to worse.

 

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3" on mine. Plenty of room there, just gotta heat sheild the booster/master since everything does sit close.

 

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Heh, that would be right in my sweet spot for sizing... enough so that I'm tempted to buy one, though I have no idea WRT to that specific model/seller. Looks very compact for what it is, I'd be a little worried WRT to real world airflow.

 

theres 2 guys i know using them on the turboforums, and i know of a few mustang guys using these too they make pretty much what a mp turbo would make powerwise


btw rom here t76 new shipped to ur door for 330 bucks

http://cgi.ebay.com/ebaymotors/3-Per...item1e645eefec

 

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Just FYI they are standard 2.5" 3 bolt header flanges. I got 2 off ebay for $5 each. I'm thinking of a scavenge pump now to fit mine in.

 

.81 will be fine,u will be rpm limited anyways because of the tpi , 6k tops and relistically more like 5,400

u want the turbo to spool up fast and be all done by 5,500 ish rpms to match the power curve of the tpi


the ebay t76's do measure an actual 76mm compressor and p-trim turbine wheels


which btw that 200 bucks u save could buy u an assortment of used ptrim turbine housings but for a tpi 305 u wont need more then the .81

 

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even still the 81 will be fine

 

The .81 will probably be OK, but it would definitely be more on the "street" side of sizing rather than a race setup...

 

psst rob this is right up ur alley

https://www.thirdgen.org/forums/engi...ml#post4953136

 

any updates??

 

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man this makes me want to set aside the 401 and try to build a 305 and see what happens. Seems like a nice challenge to try

 

ARRGGG, mine just started making a weird ticking noise last night... I'm hoping it's valvetrain... the only other engine I have sitting around is a 350... don't wanna do that...

 

you criticized me on the fact that i built mine up in my thread about building a 307

 

Wait, did you actually build a 307 or did you build a .010" over 305?

 

my dad built the 305 in the car presently, and my moms ex bf gave me the old 307 out of his chevelle that had 14xxx on it in favor for a 396. i havent built it yet, but when i get my priorities stragihtened out it will be in the works. i had a wierd idea for it but im not sure it would work without extensive machining

 

not entirely odd if you have the parts... there have been a few engine masters entries that started with 307 blocks, one that won...

 

The only thing about a 307 is they are a bit harder to get pistons for. Expect that to come up. If you're doing a stock bottom end shove a cam in it and have fun. I would do a cam pretty much no matter what 307s were known for eating them.

 

so maybe i was wrong, im sure you will easily be able to fit a pt88 on the bbs design single headers, my headers arent too different from the bbs just my turbo is alot further forward, when i built them i just had the mpt70 and i thought it was a nice tight fit, but this pt88 fits just fine and doesnt hit anything at all. my only concern right now is hood clearance but i had like 1.5" all around on the mpt70.

i say go with the 88mm

 

I thought you said you were gonna run your car naturally aspirated down the track first and then opt for the turbo(s)... Did I miss something??

Dan

 

i kinda wanted to see if a 350 crank and a.30 overbore would work, just for ***** and giggles, otherwise i think a cam and a little work with a turbo would make a decent driver engine

 

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I dont believe this is correct....i cant find one post that I've criticized you on your build...in fact I dont see any build threads that you started???

 

eh i thought you commented against the idea on my 307 thread, sorry i got a little defensive, i meant it in a sorta joking way but it was still uncalled for. oh well not a big deal, i shouldnt have said anything, my sincere apologies, but now back to the thread

 

Def an oddball combo but I bet you could do it with some stock 400 rods and stock 307 slugs. Piston selection is sorta limited though.

The other thing is that 283 slugs are the same bore I believe, but you'd have to run the 307 crank and 400 rods or you'd have to run a 3.0 stroke crank and 5.7 rods.

Another cool combo for this could be a 283 crank and then using 307 slugs with 5.94 rods out of a 4.3L V8. It would be a 283 but give better pin height than a regular 283 would.

With some custom slugs there are a TON of combos out there for a 307 with rod and stroke, I'd almost be inclined to do a 400 crank in the block if I was going to that expense (which I wouldn't really, I'd be inclined to do the 350 crank/5.565 rods and 307 slugs if anything.)

As a last alternative something that is a little on the exotic order that could be doable is LS1 pistons. You'd have to match the right set of rods up to the right slugs to make it work but they have the same pin diameter and a set of

Some thing like ross 99837 would let you use a 400 crank, 6" rods and leave 5 thousandths for the deck to be cut. Could be a wicked combo overall and would probably be about 360 CID in a 307 block.

 

what are you reffering to as slugs?

 

Pistons. I'm not sure on the model though they may be pushing the rings WAY up to get that C/H. Not too sure it'd do well with forced induction. On the plus side if you kept the stock chamber volume and increased the stroke to 3.75 you would gain a lot of compression. For nitrous or a N/A engine the easiest thing to do to a 307 would be 305 heads that are ported some or L98 aluminum heads and a cam. That would make it make a lot more power than it did initially. For boost some 350 Vortecs and a cam would make it run very well I imagine.

 

does the 350 cranks stroke have enough clearance for the pistons walls though? and with 6 in rods youd be using around 1.6 rocker arms i think