Grants89iroc-z

Hey guys, i was trying to find out all i needed to know on how to do this intake swap!The car is a 1989 iroc-z with a 350 tpi. I am only running 305 injectors which i believe are 19#? so if i get the lt1 intake, from a pick-n-pull i will grab the whole assembly as well. Such as injectors, fuel rail, everything needed!

Will this intake bolt right on? I will just be installing this intake and nothing else, no Heads or cam (for now). Im going to have to make a dizzy hole right?

Just basically i would like to know as much as possible about doing this swap!

Thanks!

xclrate

Subscribed! I'm interested in doing this also.

flaming-ford

iTrader: (7)

no it doesnt just bolt on...... the ports will need to be raised by welding material to the top of the runner exits. or a high temprature epoxy.

also you will need to have a remote thermostat housing.

the hole for the dizzy sits at a slight angle as well btw.... something to keep in mind, its not just an easy (cut the hole and your done) hence why im not currently using 1 lol......

use your search feature and you will find out more than you need to know about the swap.

Grants89iroc-z

i have tried to use my "search feature" and every time i find something about this, i find an old posting from years ago and they all say to go to lt1intake.com which is a no longer available website!

vetteoz

iTrader: (13)

Google works

http://www.s10wildside.com/wildside/lt1induction.htm
http://forums.corvetteforum.com/c4-t...or-an-l98.html
http://www.popularhotrodding.com/tec...ls1/index.html
http://sethirdgen.org/LT1.htm

Grants89iroc-z

Thanks a lot vetteoz! Those seem like very good sources, i would have never found those!

Grants89iroc-z

Even after looking at those websites, it doesnt really tell me "how" to do it.
The only real thing that i know about this swap is that you will need to make a dizzy hole. But what happens to the thermostat? I hear about these Remote thermostats but i cant figure out what they are and how they work! Where is this thing mounted??

Thanks

vetteoz

iTrader: (13)

Couldn't be much clearer especially with the pic in the wildside link

Problem #3,
No front coolant passages to return to the radiator. I just drilled and tapped two 3/4" heater nipples vertically where the coolant would normally exit the head. I will run 3/4" heater hose to a remote thermostat housing I found on-line. it will be mounted on the fender well. It will use the same outlet neck and return to the radiator as it should.

vetteoz

iTrader: (13)

As stated in the links you drill and tap the manifold for 2 pipe fittings.You then run 2 heaters hose to a remote thermo housing like this

http://www.streetperformance.com/par...8-7134win.html

which houses the thermostat and allows you to join to the radiator hose .You mount the housing anywhere you like out the front where it is easy to hook up the radiator hose

Street Lethal

iTrader: (16)

What timing, as I'm finishing mine up today. Only the outer four bolt holes are in the correct location, as the other ones need to drilled. However, all of the holes are not angled properly, so even the outer ones need to be adjusted a little. You can simply do what I did, weld them all shut, then re-drill them the right way. As for the distrubutor hole, some guys drill their hole then spend the rest of the time glopping on the weld, then trimming it down to get it right. What I did, was, I took a donor TPI intake and cut off what I needed, and as fate would have it, am welding it in today. The EGR ports, or lack thereof, on the chinawall (top and bottom) need to be added to otherwise it will leak, so be sure to either add about a 1/4" of weld top and bottom, or simply run heads that don't have EGR. I didn't do this, because the cylinder heads that I'm using don't have EGR. Get yourself a coolant fitting off of any LG4 intake manifold (or simply buy one at Home Depot), and drill and tap the area that you want in the intake, just make sure the port in the location you choose is open on the cylinder head. The remote thermostat itself is the easy part, just decide on a location for it...

Grants89iroc-z

okay so you can run egr on this intake, which is what im going to have to do.

So i understand the part about drilling my own holes to bolt the intake on, got that.
Weld in dizzy hole from a donor tpi intake.
Make your own coolant passage so it can return to radiator.
install the egr on back on intake

That should be it right? it should work after that?

Street Lethal

iTrader: (16)

No. You need to address the EGR ports on the cylinder heads, that is what I was referring to. You can either weld up the EGR ports in the heads, or enlargen the chinawall's center (top and bottom) on the LT1 intake where it meets the cylinder head EGR ports, otherwise it'll leak.

Grants89iroc-z

so your saying that if i put the egr from my tpi intake, and put it on the lt1 intake, it will leak??

Street Lethal

iTrader: (16)

No. You CANNOT use your EGR valve on the LT1 inatake, it will hit the distributor. The chinawall (sides) of the LT1 intake does not have an EGR port to connect to the heads, at all, so you need to do something in relation with your TPI's cylinder heads that DO have the EGR ports. The cylinder heads will leak if you don't correct that area, not the LT1 intake itself....

Grants89iroc-z

Okay! im starting to get this now..So i just put a block off plate on the back of the intake. Since i cant use my EGR valve there becuase it will hit the distributor.
So if you cant mount the egr on the intake, Where do you put it??

Street Lethal

iTrader: (16)

Most guys don't bother running an EGR w/the LT1 intake swap, they simply block it off, and call it a day. You can however fab up something to work similar to the 2.8/3.1 V6's, where it comes directly off of the exhaust manifold into the side of plenum, but that will take some fabrication. You don't need EGR, you only need it to pass a visual inspection, the engine will run just fine without it when you disable EGR from the prom....

Grants89iroc-z

What would happen if i did NOT disable it from the prom, and still blocked off the EGR?

Street Lethal

iTrader: (16)

It will trigger an SES code in the ECM. Some people blame the code for the occassional hiccup, but that is still open for debate. I would simply disable it if I were you, unless you like seeing the SES light trigger....

Grants89iroc-z

well it would seem a lot easier to not go into the prom, since i dont have any computer programs to change prom settings

But there wouldnt be any damages if i didnt change the prom right?

like im not going to ruin my engine because i was lazy am i?

Street Lethal

iTrader: (16)

.... the engine will go KABOOM if you don't!



















































.... just kidding.

You'll be fine, you can always have someone burn a chip for you....

Grants89iroc-z

lol yeahh, Thanks for answering all my questions lol.

Maybe later in the future this will be a project for me but if i do any intake work, ill probably just be porting my intake for now! But first..i gotta fix my car first

Bullydawg

iTrader: (7)

Or you can buy them on ebay with the dizzy hole drilled, and and manifold bolts redone for like $150 I think.

Grants89iroc-z

i looked on ebay and cant find any custom lt1 intake for the 1st gen engines.
It would be great just to buy an intake that had all the work done to it, like the bolt holes in the right spot, basically where i can just bolt it onto my engine.

If anyone is selling an lt1 intake thats modified i might be interested in buying!

vetteoz

iTrader: (13)

Interested to see how you go.
Was intending doing major mods on mine requiring welding but machinist thought the intake would warp.
Machined off all EGR bosses so HEI would fit , was going to plate over holes and and weld a alum block for dist hole / mount and have machined to correct angle so as not to have the oil leak potential with the angled spacer most use

Grants89iroc-z

Would there be any power gains by just doing this intake swap and nothing else??

300hpse

iTrader: (2)

I would imagine a pretty noticable loss in low end torque but you would pick up some high end hp. The lt1 intake is the opposite of tpi, very short "runners". I guess depending on your motor and what you like out of your car, it's not a bad idea.

Grants89iroc-z

yeah i did hear that you lose the low end torque, and get more high end power.
But it is probably better since when you wanna haul *** your revs are high ya know? and tpi doesnt make power up in the higher rpms! So the lt1 intake probably pulls a lot more in the higher in the rpms than the tpi ever would.

But what i was really tryin to figure out is like, what would the time difference be in say 0-60 or 1/4 between the two intakes?
Same times? just different mph?

300hpse

iTrader: (2)

Id like to know too but it's difficult to find actual posted results from a lot of mods here. Hopefully someone who's done it can chime in with some details of their experience.

3rdgenred

iTrader: (1)

My questions is about the fuel pressure regulator. The TPI regulator sits under the old plenum cause it's raised. My question is if this new LT1 intake sits flush, how are you going to mount the fuel pressure regulator? Does it need to be mounted somewhere else in the engine, then have fuel lines run to the fuel rails?

vetteoz

iTrader: (13)

On a LT1 the regulator is at the end of the drv side rail .

http://cgi.ebay.com/ebaymotors/LT1-L...item439afa090e

You either attach your new custom lines to the existing LT1 rails or you weld -AN fittings on the rails and use a remote reg

xclrate

Does anyone on this board or anywhere else sell a complete intake with the mods already done?

3rdgenred

iTrader: (1)

Yeah I was thinking that. Was there someplace that you can buy this already modded. And with the new upper intake, do you need a new base? Or can you use the old tpi base?

xclrate

There is no base or upper. The lt1 is a one piece unit.

3rdgenred

iTrader: (1)

So you can simply just buy the lt1 intake manifold, and do all the mods, then jar take off your runners, plenum, and lower intake and slap on that lt1 and your good to go?

3rdgenred

iTrader: (1)

So you can simply just buy the lt1 intake manifold, and do all the mods, then just take off your runners, plenum, and lower intake and slap on that lt1 and your good to go?

xclrate

I guess you can,but the mods usually take anyone 2 to 8 hours to complete. I just don't have the time to do it myself. I'd rather buy it already done from someone who has done it a few times.

Grants89iroc-z

if i had welding tools and an lt1 intake i would do this for sure! but i dont have welding tools lol, so i wanted to buy one madee

3rdgenred

iTrader: (1)

Now my next question is if you swap to the LT1 intake, do you need to swap to vortec style heads? I know that heads would also not be a bad idea to do at the same time but would the bolt patter on your stock L98 heads match up?

Grants89iroc-z

i found this from another website
"From LT1intake.com:

Will the LT1 intake fit Vortec heads?

No, it will not fit. The intake mating flange is too narrow to cover the tall ports that the Vortec head uses. Fastburn heads are drilled with both standard SBC and Vortec bolt patterns."

Red89C4

Are there any updates on this setup? I'm now getting all the parts together for the swap on my 89 Vette and I'm having problems with the intake gasket. I was told that the Fel-Pro 1205 works, but it has some "issues" on sealing to the rear of the manifold where the "new" water outlet nipples go. As soon as I can get the gasket thing taken care of, I'm hoping to get it installed, but for now I'm getting data on the "before" drag strip times so I can see what this "manifold only" change offers.