New here,

This is my first post, although I've been reading this forum for several months.

I had picked up an 88 Iroc in August as a gift for my GF and since then she has driven the car no more than 5 times

Any old way.. I have, to my surprise fallen in love with the car. I've primarily owned european cars, some N/A and some have been turbo builds, as well as many bikes. These include a big turbo Passat - 297 at the wheels, an 06 Audi S4 V8, my current 530is - 100% stock - daily driver, 03 Buell XB9R, an 04 Gixxer 600, Custom xs650 bobber to name some.

This however will be my first turbo project o an NA car.

I have read the infinite posts about the futility of modding a 305, however I, like some others on here can't afford to sink big bucks into this car and I'm content to swap to a 350 or larger when the 305 quits on me.

For the time being, I want to put my build plan on here and get feedback if i can about how i can do it better. My budget for this project is not to exceed 3000, but I'd like to stay under 2 if possible. I already have many turbo related components from previous builds such as intercoolers, piping, bov's etc.

So heres what Id like to do, tell me if I'm missing anything.

Turbonetics T60 or T70 journal bearing
350 heads
30lb injectors
MegaSquirt II (convert to MAP)
oil cooler
wideband o2

I am planning on running 10lbs of boost, no more than 15 on this motor.
This will be a weekend car for around town.

Thanks in advance for the input and thanks also for all the great info on this forum that has inspired me to not let this great car go unmodded

Regards,

Josh
Cape Cod, Ma

 

its not all watsed on the 305 specially if ur going to build a turbo syste. any turbo system u build will swap onto a 350 or even 400sbc that u may swap in down the road


ur parts list looks good except for one thing 30# injectors u will need atleast 42's though i would start with 50's

 

Not sure you really need 350 heads for the 305 if running 10 lbs of boost but the lower compression would be nicer/safer. Other than that, looks good. T60 would be fine for 400whp or so. Possibly some more but doubt you'll see it on less than 15psi, hard to say tho. 42's would work great for that. 30's set on high pressure may work but it be close. 36's-42's would be better. 42's at our pressures would be good to likely 500-550whp. Thats good since regular walbro on stock voltages shouldnt be pushed too much over 500whp anyway.

 

Thanks for the quick replys u guys! Im definately goin w 350 head to play it safe! Thanks for the suggestion about the injector size. Ill go with 42s bc i can use em again with more boost when i go 350.

 

as im sure u know boost is adictive , so get an injector that will support mor epower then what u want right now.anywhich way u look at it u will have to tune it once u get it together, so get the larger injectors it will give the entire system more room to grow down the road and wether u buy 42's / 50's or 60's more then likley they will cost u the same price


its like on my car i started with 65#'s and i knew i was going to be shooting for more power eventually so now im going to have to spend another 4-600 bucks on even larger injectors , should have just bought 90 or 120's to begin with

 

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i wanted to update with a bit of progress. new serp belt installed. fmic installed, all intake stuff save TPI has been removed and rear end is almost dropped. next up exhaust and herders are coming off, then some 350 heads and new headers w manifold for single t70 going in

 

throw you a lt1 cam { 50 bucks used ) some roller rocker arms . if your gonna change the heads go with vortecs they flow way better than old school 350 heads .i'm doing the exact same thing to mine then over the winter i'm gonna build a forged 350 to handle the boost an horsepower level i want . i'm gonna use a t70 . good luck an keep us posted

 

intercooler in

 

who take photos less than 1mb? this isn't 1990... lol having trouble uploading 2.5 - 3mb photos.... any suggestions

 

sooo, am i looking for 64cc heads? vortec/aluminum heads aren't in the budget. what heads and what size gasket do i need to get compression as low as is reasonably safe with boost? thanks!!!!!

 

If your not looking to go beyond 15-psi, keep it between 9.0:1 - 9.5:1. Keep your stock heads (port them), and have Cometics cut you a set of MLS head gaskets that will bring your compression wherever you want it to be...

 

What is this

I can see that its some kind of emmissions related thing.. It goes to the cat and the headers. There are 2 electrical plugs in it. Does anyone know what they are. Im pullin headers next and the new headers w/ turbo manifold dont have place for this. Im sure its nothin important but jw what it is

 

I would reccomend you look into a tc78 turbo.
Esp. If u ever plan on stepping up to a bigger motor.
Invest ur cash on good arp headbolts, but i would go with headstuds, and they can be used on bigger motor also if need. If u can find a good low price head gasket. Should be fine for 10psi. Invest ur cash in fuel system and injectors. 60lb. Also give room to grow.

 

Thx for suggestion. Im going w 50 or 60 lb injectors for sure i have an ebay t70 already( from previous build) so ill use it till it blows. Im going w turbonetics t70 at that point for sure. Im going to port and polish my heads and just get a thicker head gasket.

 

That is the air pump diverter valve(s) in the pic you posted. Hey i wont tell anyone if you remove it. (BTW if you live in a state where the do smog tests, you kinda need that)

Oh btw, you can also remove the air pump below that, there is gonna be a black tube running down to the pump once you unbolt the diverter valve. 2 10 mm bolts i believe.

Also, it may help to just cut the tubes going to the headers if your not gonna reuse them. Unless yours come off easily.

 

Thanks for not tellin man. Guess the goin in the trash!

 

t 70 is ideal for your build
you can always go t88
later

 

and suggestions about head gasket thickness, I'm looking to be at 9:1 pre boost or as low as is feasible.

 

more pics coming soon. rear end dropped. headers will be coming out next!

 

IDK WTF just happend, i made a post and hit edit by mistake and **** just went crazy on my computer, Original post was deleted.

As i said before you should be able to get to 9.1 to 1 comp with a stock head gasket using l98 steel 350 heads on your 305. IIRC the 350 heads have 64 cc chamber and the 305 have a 58cc chamber.

 

0.051 Head Gasket will bring you just below 9.0:1

 

Hey street. Is that with the 305 heads? Or the 350 heads?

 

Both. The 64cc and 58cc heads both came from the factory with 0.021 compressed head gaskets, and none of the LB9/L98's exceeded 9.5:1 from the factory on our cars, and with compression say at 9.5:1 using the factory 0.021 compressed head gaskets, swapping to 0.051 gaskets will essentially bring the compression level down to 8.96:1 (from 9.5:1). His '88 305 is said to of came with 9:3.1 compression from the factory, so it should be a tad lower than 8.96:1 which of course is to his benefit because that will give him more effective compression (ECR) to utilize. The only problem though is we don't know if his 305 cylinder heads were ever milled at all through the years, as some owners have them cut down to bump up compression or just to resurface them, so he needs to be sure to check for any markings/scribes on the stock heads...

 

You may have to school me on this one street, but as much as i know, i have always thought that comb chamber cc has an effect on comp ratio, along w piston cc and head gasket ring cc ??

 

Nothing to school, your absolutely right. Remember that I am using the stock engine compression rating, with the stock head gasket thickness of (0.021). I am also using 9:5.1 static compression just as a base to arrive to at 8.96:1 when swapping to the thicker head gasket (0.051) from 0.021. Both the LB9's and L98's came from the factory with the same head gasket thickness (0.021), but they slightly varied in static compression because of their different cc's, but that compression level was very close to 9:5.1 being used as the base. For each decrease in cc you will increase compression by 0.1. His 305 came with 9:3.1 from the factory using a 0.021 compressed gasket, so by swapping to a 0.051 gasket his compression will be slightly lower than 8.96:1 (if the stock heads weren't touched)...

 

Oh thank god, I figured i have been giving people **** info for years. Thanks alot. I got to stop second guessing myself.

 

thanks guys. awesome info. i will need to take a look at the heads once i get them off to see if they have ever been milled. still gotta get headers out first. looking a bit ominous.... lotsa rust. I'm going to tackle it on my next day off tho!

 

thought id update. she's a real beauty

 

heres my new toy ( the silver S4)
gottA LOVE A GERMAN V8!

 

Wanted to update with progress. It has been slow as ive had to devote resources to my other vehicle. However- i did finish ordering parts last night. Heres what ive got. Ebay t70, MSD, bosch 62lb injectors, walbro255, spearco intercooler, EBL flash, xs piwer single turbo header-very happy with this part btw! I have turbo headers almost mounted up as well As intercooler. Next step is to finish header installation(some minor clearance issues), pull off tpi and get the new injectors, fuel pump and get this bitch goin! Sooo pumped!

 

Wouldn't using 350 heads on a 305 cause valve shrounding issues due to the very small bore of the 305.

 

We have decided against changing out heads actually. We just gonna see what shes got with a quality tune.

 

i still love the way a bone stock (externally) iroc looks. put some fresh paint and decals on it, and it will be sweet. i like where you are going with it, gonna stay tuned.

 

Gonna go way off the wall with the lookis of the car. Gonna keep the paint. Drop it low, tryin to find a set of watanabes (see:http://www.jdmlegends.com/wp-content..._27_10-021.jpg) and gonna put two stripes in middle but in a sticker bomb style (see:http://s1.blomedia.pl/autokult.pl/im...ltstylepl-.jpg). I cant wait

 

gonna jdm an iroc?

 

Please dont flame. (Not saying u are but im sure its coming- lol... Its aight tho.) Just gonna make it a reflection of the styles i love most. The stickers are up in the air but watanabes for sure! Gotta admit that a 71 skyline looks cool no matter what ur in to.

 

sorry not trying to flame. sticker bombed hoods are all the craze down here on the hondas. also "stanced" cars are popular. neither of which are my cup o' tea. i also don't like krylon'd black wheels, grand sport stripes on cars other than vettes, or 8" smoke stacks on diesels.
lol.

 

To each his own. I own a stanced audi s4 as my DD and my next project will be my buddys boosted 96 nissan se-r. American muscle is awesome and there is not other car ive owned that ive felt such a connection to as my iroc. Shes just beautiful. The sticker bombing is not a definate yet btw but i do think there is something so badass about a boosted n slammed iroc on old school japanese wheels! Im taklin custom 12 or 11x15 or 16 watanabes!

 

the picture in the shopping plaza looks kinda familiar?blackstone valley shoppes?

 

No. Thats on cape cod. (plaza that i work in)

 

AHH ok...looks like one of the plazas out this way...lol

 

I can think of three or four places around here that look just like that too.

 

You're going to run into a fuel problem unless you switch out the fuel pump. I used the Racetronix kit. But then you're gonna find that you need to convert the fuel lines to 6AN or at least the return line to 3/8 instead of the stock 5/8. That kink in the fuel line where it connects to the fuel rail proved problematic for ACCEL so they sold the jumper lines and fittings if you were just going to stay under 500HP (The Lingenfelter SR system was set up with the cam for 440HP.)

 

You should really consider at least doing a mild cam with springs. Chances are the springs are very worn and will hold you back alot at WOT and 3500 RPMs. And given the size of the stock cam in an 87 LB9, even a take out LT1 or ZZ4 cam will bump up the power noticeablly.

And Very cool build!
Its cool to see a tuner guy discover joy of a Thirdgen.