i was just wondering if anyone has used the edelbrock high flow tpi system and how good it works because i was thinking about buying one. any help woill be appreciated. thanks

p.s. i was also wonder if its worth it to buy tb spacers and if there is any improvement with them. thanks again

 

anybody?

 

any of the aftermarket bases are good to get. the stock base is the most restrictive part of the TPI system. i'd recommend also getting some SLP runners and porting the plenum.

 

stock edelbrock system needs porting to truely gain performance

i got a accel superam base that i'm porting and there is TONS of room to work with. definately needs ported

 

Buy it used, not worth it new. For the price of new, you could have your stock base and plenum extrude honed. The quality of the edelbrock base is suspect. I had to search through the back room through 5 intakes to find the one with the least amount of casting flash, and the straightest ports. Still had to port them afterwards.

 

I have one . Base and runners. It's siamesed in 4" and base ij just cleaned up a bit . My plenum is ported and siamesed ( except behind the TB bores ) . I like it so far . But I had kinda though that if I opened up the runner the way I did I would see a more higher peak of the HP . But still it peaked at 4900 tehn lost about 20 hp by 5500 rpm. Which isnt the deadstop that the TPI is noted for but it still faded at around the same point ....just less so

 

D's89,
i think u could make abit more power at a higher rpm with a different cam.. zz4 is nice but leaves alot to be desired

 

i got a accel base hogged out with SLP runners and ported plenum. A must if you wanna go fast in a TPI car. I cant complain, i love my set-up.

 

I hear ya there ( I just figured the intake in its currnet state would hit the 5500 mark--> they say ZZ4 tops out at 5500 ) . I had one picked out but now I got a turbo to think about ....so it all changes again It would be nice to have everything flowed .


As far as TB spacers . Junk leave'm alone . Not worth the time to put them on ....unless you were carbed.

 

You're not going to see a huge shift north in the power band...although I would have expected a 200 or so rpm shift up in the power band. You'll still have fall off but honestly 20 hp fall off isn't too bad at all from 4900 to 5500. On my LT1 car I had a peak of 264 rwhp in stock trim, and it fell of from its peak at around 5200 to about 250 rwhp at 5700. So 20 hp with a TPI setup isnt bad.

 

I put the Edelbrock TPI base on my 350 L98. the intake runners need to be cleaned up, Edelbrock CNC machines the port entries, but leaves a sharp transition where the machining ends at the as-cast surface. it cleans up very nicely with the grinder though. the ports are definitely bigger than the stock TPI base, use the larger Mr Gasket TPI gaskets to match. I used SLP runners. I had to grind on the rear-side of the thermostat housing, seems it's a tight fit due to the bulk of the larger manifold runner size.

I had ordered the specific part number (3861) to mate with my old-style heads, but what came in the box was a universal fit. The tops of the intake runners were machined to clear late model cyl hds, and the center 2 manifold bolt holes were the dual-angle oval jobs. I used the supplied alum spacer washers under the GM torx manifold bolts to spread the bolt load, the instructions didn't say what these were for but they mysteriously fit the machined spot-faced washer surface perfectly. you have to use the original GM torx bolts for runner clearance.

because the tops of the intake port runners are machined, you have to be careful that the manifold covers the intake manifold gasket and the intake port on the cyl hd adequately, not a lot of meat or margin for error there. I used RTV sealer to improve my chances, successfully.

had to use teflon sealer on the manifold runner attaching bolts, seems the rearmost driver-side lower runner bolts connect to the rear manifold water cross-over passage, I was wondering why I had a coolant leak at the back of the motor, thought it was the manifold gaskets. I also used teflon sealer on the front passenger side just in case of symmetrical leaks.

the bolt hole at the front of the manifold for securing the fuel line bracket didn't line up for some reason, but the fuel lines are also secured under the alternator, so that's okay.

make sure to put pipe-plugs with teflon sealer in all the unused holes. I forgot a couple of them (various sizes), and had humongous vacuum leaks at start-up. they were pretty easy to find, since they all made loud unmistakable sucking noises.

I also rerouted the cable bundles to under the plenum, instead of between the valve cover and TPI runners. cleans up the engine appearance quite a bit.

Since I changed the cyl hds and the cam and the injectors etc all at the same time, can't say how much of the monster performance increase is due just to the manifold base. I think it's a pretty good combo with the SLP siamesed runners. I ported the front of the plenum to remove the ridge at the front (behind the TB), remove the taper on the TB mating face, and port-matched the plenum to the SLP runner entries.