Black88Z

Sorry, I don't know if this is the right area to post this but I figured this is a good place to because we can have people with carbs, tpi, lt1, hsr, ect., give their two cents.

It seems like everyone hates the TPI 350. I hear people talk poorly about them all the time, and read online where people call them dogs, weak, useless, boat anchors, ect. I honestly don't understand why, my car is a fairly stock (couple bolt ons) l98 and its very fast. It has 3.73s which help of course lol but even still the engine was rated at 330 lbs torque at its earliest stage, I believe the highest was 345? So with a good exhaust and intake and small bolt ons you could be arguably close to 400lbs of torque on a nearly stock 350? I know the cars are heavy, and they weren't all geared well, but I hear people rag on TPI motors specifically, not just 3rd gens or camaros ect.

I personally think the tpi is a really cool and all the low end torque is very fun, and very street friendly. Instead of revving to 5-6k to start making power the tpi is instantly in its powerband and goes to about 4ish before it falls on its face haha but with some fairly easy and somewhat inexpensive mods the tpi can breath decent up until about 5k. the tpi is still used in autocross and people still like to mod them and make monsterous torque out of them, like myself. I haven't driven a car with a carbed 350 or even an lt1, so although I think my car is pretty fast and fun its hard for me to compare it to any other 350 car.

So hopefully we can have people with different intake setups compare and maybe find a reason for people degrading the TPI.

eseibel67

No shame in TPI. Runs really nice, it just can't scream up the tach like some other designs can.

But don't forget about the TPI best feature - it's beauty. I usually leave the hood open on my son's GTA just so I can look at those pipes when I'm walking through the garage.

mjdavis68

iTrader: (1)

Yea why is that? i bought one that some stupid *** took it off and put a QUADRAJUNK on and butchered the harness.

formula forever

Its because people can't seem to see the history behind TPI. gm struggled in the 1980s trying to make power and still have an emission frendly engine. then They achieved that. It does pack a nice punch and is a good stoplight to stoplight racer. I think people just have to High of an expectation because of LS1 motors and how easy it seems to make power with newer cars.

deadbird

Because as long as guys have *****, the only thing they can worry about is how much more power can it make.

backgammon7

Look at a thirdgen from the outside and tell what engine it has. Some idiot claimed to have a TPI 350 when he had TBI 305 and got his doors blown off, the victor then trashes the 350.

rgarcia63

I work for an Oil Company in the R&D department sometimes they have seminars and use engines with cut outs to show the internals, but there's one engine they show that could be dropped in a vehicle ready to run and that engine is a TPI. I was actually surprised to see an almost identical TPI to my own, not matter what other engines they had the TPI gets a crowd.

Black88Z

All good points. I also think that because people are unfamiliar with it, sometimes they tend to "knock it before you try it". A friend of mine had an lt1 trans am (90s) and always talked about how fast it was. The he rode in another freinds 90s ws6 lt1 and said it was even faster. He had never riden in mine before, so when I took him out for a ride he couldn't believe how fast the car is. The person I bought the car from put 205-65 15s on it so even when its dry out if I floor it going slow/stopped it just spins. I told him I was spinning the tires until about 15mph until I hooked and he was impressed. Hee said he had no idea it was that powerful, and just by looking at the car and knowing its an 80s engine he didn't think it'd be that impressive. He said my car would have destroyed his and he wasn't sure who would win between me or the ws6,but it'd be close.

Just seems wrong that people knock the l98 when they know nothing about it. I do agree that a lot of 3rd gen owners tell everyone its a 350tpi and race people, giving the motor a bad rep. (No offense to other motors of course) I know a few people that do that

Orr89RocZ

iTrader: (20)

You buy these cars for performance. In the hunt for speed tpi just doesnt compare to other setups. Its only been in the last few years guys are figuring out that welding up the bases and extensively porting them and making huge tube runners or greatly siamesing them, you can get some performance out of them. However its alot of work and weld time, lots of cost if you cant do it yourself. Other intakes out there get it done for less.

Tpi in its design is long runner which promotes low rpm tuning. Lower rpms means less hp potential. Sure torque is fun but hp makes speed. Thats why guys knock it. Its a limited performance engine.

Try it for yourself. If you think your L98 with bolt ons is fast, take it to a track and get some times. Then swap to a short runner intake and retune. You will be very impressed with the difference. I know i was. Gm could have thrown on an LT1 type intake and made a faster more powerful car meeting emissions no problem but TPI was designed for a 305 to make torque like a 350 and feel faster than it was. When gm decided to go 350 they missed the boat with the design and had a handicapped motor. Shorter runners on a 350 would have went along way

cuisinartvette

^^^^
What he said

They kind of "feel fast" due to the throttle response

But they are not...if youve been in a "fast" car then drive the TPI youll cry.


They are great cruisers and can rip up to speed limits fairly well if you play with them they have their place.

Its about all GM had to work with in the 80s, it is what it is.

IROCZ1989

iTrader: (1)

I think if you love the look of the TPI engine as most do and you wanted a barn burnee, the best intake would be the First setup. Stock has its limitations which can be extended greatly by use of a power adder such as nos or boost. 1/4 mile they are tough to modd as they run out of steam on the top end. For the track they cant be beat out of the corners because of the massive torque they produce. These cars were corner carvers before they were 1/4 mile pounders.

I think the best conversation we could ever have about this intake is about the design. Who came up with this? No matter how new the technology the look of the tpi blows them away. Im sorry if i offend anyone but lt1 intakes have no style as does the miniram. Super ram I can live with. As with the First setup. I wpuld definatly love to read the background story on this intake and see actual conceptions of it before final design. Just blows my mind.

cIaRmOaCrZo

thats all i see when going to buy an iroc. its frustrating, i swear people cant diagnose a check engine light, so they rip off the tpi...just hillbilly as hell to me

Black88Z

Lol I've seen that a lot too. Its so easy to run the codes on the obd1 cars, all u need is a paper clip. Nut I agree about the tpi "beauty", its definetly very unique and a lot of people have mever seen tpi before so it draws a crowd of curious people. I'm planning on keeping tpi for my car, my other cars will be carbed. But for a street car- light to light racer, its hard to beat the tpi.

Btw, what is First setup? I've never heard of it. I'm. Guessing its an alternative to tpi, but of course typing that into google resulted in everything but that haha. Too generic for google.

cuisinartvette

FIRST intake is like a king size TPI the way chevy shoulda done it.
Imagine that on a 400cid motor stock wow. That woulda been fun.

The superram to me is the ugliest pita to assemble manifold ever
BUt they work like a **** and are very versatile. Not to mention smog legal!
Think John got that one right too bad noone makes something similar with a larger base/runner.

Black88Z

That's interesting. I did some research but it seems first isn't very well known and I couldn't even find any horsepower or torque numbers. I'm sure its a huge improvement over stock, but does anybody have the first intake? Or at least seen some numbers for it?

hondastyle

Wasn't the cam in or the heads in the l98 the same as in the lb9? I know using the same intake while sure it saved on cost put a huge cripple on the engine.
Long tiny runners while worked ok for the lb9 just doesn't cut it on the l98.
It's as though chevy did everything they could to make sure the l98 couldn't breath as well as it should be able to. Sure it in the end made it a have a decent amount of torque but it just ran out of steam so quick and the powerband was so short.

BlackenedBird

iTrader: (5)

Your off by 100hp. The highest ever factory rating was 245hp.

But people "look down on them" because they have no top end power (stock) & run out of steam by 4500. For a 1/4 mile drag race car that is not exactly the best. For a street car? That is fine & the abundance of torque is a great thing.

sofakingdom

iTrader: (1)

That's pretty much the long and the short of it, right there.

Of course they could have done AHELLUVALOT better, if the bureaucracy hadn't been so hide-bound.

TPI was state-of-the-art in new cars for about 2 years. The competition then proceeded to pass it like it was standing still. (literally) And worst of all, it is arguably the absolute MOST MOD-HOSTILE intake setup ever made; its limits are all but impossible to overcome to any more than a marginal degree except by forced induction.

I would in fact argue that GM's failure to keep up with the times as EFI was RAPIDLY evolving AROUND AND BEYOND it during the marketplace lifetime of TPI in their cars, remains the reason to this day that other companies have a leg up on it in the "performance car" marketplace. It was so bad for so long that it damaged GM's reputation so bad that it allowed EVEN XLER to get back into the game. That's PITIFUL.

The L98/ZZ4 comparison shines a GLARING spotlight on its deficiencies. Take a block, some pistons, some heads; put a mild street cam and a carb on it, you get 345 HP. Same block, same pistons, same heads, but TPI instead and a cam optimized for it, and voilà! make your HP disappear as if by magic!! 245 HP. 100 HP less. Now granted the "ratings" systems are WAY different, so those #s aren't apples to apples; but after putting the ZZ4 in a chassis and "rating" it the same way, there's probably still a 40 - 50 HP difference.

THAT'S why people (and me, too) "talk s*** about TPI"... because IT SUCKS, regardless of whether it was "all there was" in 1985 or not.

Orr89RocZ

iTrader: (20)

Actually highest rated tpi was around 403 hp. Factory callaway twin turbo vettes, B2K optioned L98's 565 lb ft torque. Talk about diesel

topteam54

iTrader: (4)

Define "fast" cars??

irocwagon

I believe he was quoting torque

sofakingdom

iTrader: (1)

I guess to some extent that depends on your definition of "factory"...

No; HP.

I would also add, "up to speed limits" REALLY refers to 1980s (early 80s, at the time of the design) speed limits; 55 mph nationally. A stock LB9 or L98 will get its head handed to it on a 70 mph highway in 2013, by minivans, econocommuterboxes, and luxo barges; LET ALONE "fast" cars.

Orr89RocZ

iTrader: (20)

They made tens of thousands of callaways offered thru dealers with gm warranty from what i read. Sorta like a SLP SS 4th gen fbody in the late 90's-02 i suppose

IROCZ1989

iTrader: (1)

Here is a link with some info and alot of pics to get you started. Make sure you see the plenum comparison pic. It truly is a tpi on steroids.


https://www.thirdgen.org/forums/grou...ction-tpi.html

sofakingdom

iTrader: (1)

Never seen even ONE in the flesh, myself. Now granted, I haven't even BEEN IN all 50 states, so maybe they all got sent to somewhere I've never been (Maine, Alaska, the Dakotas) ...,,,,,.... but ... then again, maybe not.

I don't read too many magazine articles about stuff like that (or much of anything else for that matter). I pay more attention to DEALER LOTS when I'm TEST-DRIVING CARS, and of course, THE ROAD.

Considering that there's only something in the 30-odd 1,000 range of Vettes made per year, and the Callaway deal was only available for a limited # of years, then I think that's a little ... enthusiastic.

TPI's problem (which is also its strong point, as long as you don't want your motor to ever even approach 5000 RPM) isn't the plenum. It's THE RUNNERS, and their length.

Orr89RocZ

iTrader: (20)

I seen 3-4 in my life All at vette shows and other big car shows. 1 was for sale

sofakingdom

iTrader: (1)

Against .... how many ,,, ... that weren't that kind?

I saw more regular Vettes than that just on my way to work this morning.

I'm betting that the ACTUAL production #s were in the low 100s. Well under 1% of all Vettes during their production run.

Black88Z

That's a very interesting thread and I'm quite interested in it.I still didn't see any horsepower or torque numbers though, maybe I missed them. But I did see it said 15hp gain on stock motor, then I think I saw where it said 30+hp on stock motor. But rebuild with good cam heads exhaust and tune and it should be very fast. Any numbers to compare with?

Orr89RocZ

iTrader: (20)

I take that back, under 500 were made... My original link said 36,000 but that must have been base vettes. But still it was a option and dealers sold them with gm warranty

jensen73110

iTrader: (4)

Anyway, you've also gotta remember there are a lot of "younger" peeps driving that weren't back when these cars were new (like me). They don't understand how good we have it now. Every economy car had well under 100 hp. Unless it had a turbo, then that hot hatch might have 125hp. I have an engine modifying book from the early '80s that talks about how "the 400 hp v8 is gone from the showrooms forever." Now the Mustang GT has more than that, and everyone shrugs at it because it's common. TPI was great for '85, and it still looks awesome today. But 245hp is a joke today. A new v6 Camry has 268hp in a beigemobile family transportation appliance. People compare L98s to that and just shake their head without understanding the history.

IROCZ1989

iTrader: (1)

Actually hes right, hes talking tq #s. Vettes in top form made 345 lb/ ft.
This intake has potential. The runners are said to be 1.7 on the inside which supposedly a fulley extruded honed slp runner cannot touch until its cut and welded and even then its off. In that post the op ported his first runners out to 1.9 inches inside dia. Intake base and runners are said to flow 300cfm. Way more than even an extrude honed accel base. Which I think is in the 240-260 range, and lest not forget extrude honing is extremly expensive. For $1000 out the door complete its a deal. Plus the runner length is about 1 inche or so shorter than a tpi. That coupled with a bigger plenum and 300cfm capability Im quite sure rpms will not fall off like the stock tpi.
I spoke with Ken via email and gave him all my #s on my tahoes 383. 478ftlbs with a single plane. He thinks with my motor combo and an out of the box first 550ftlbs is very possible. Motor made 430hp so I am assuming i will gain a few there. Just look threw that thead I posted and resrch BadSS user name, he has a ton of posts on this intake. On his combo he ran faster and shifter lower than same motor with hsr. Plus Ken just retooled the plenum for more airflow. If I can sell my hsr system Im getting into one of these.

Supposidly the intake base will take a 1207 gasket if im not mistaken. For ***** and giggles can you imagine a na big cube 427 or 454 small block with this intake and 220 heads? Im sure 600+ftlbs would be doable. Look at the plenum comparison, it dwarfs the stock unit and its runners by eye shot. Hope this helps with the info some on this manifold. Maybe I see a gp in the near future? Take care.

Jeffs82TA

iTrader: (1)

Highest factory 5.7 TPI was 250hp but it was a vette.

Podium

iTrader: (2)

Tpi is the best truck motor never put in a truck. My moms 1.8t passat absolutely demolished my 87 trans am tpi when we raced on the freeway. Lol

InfernalVortex

iTrader: (4)

The First system isnt really all that proven. Give me dyno numbers and track times and we'll see how awesome that FIRST system actually is. it's still a tuned runner system and is still likely completely crippled at higher RPMs where all the power is made, even if it's higher than a stock TPI.

jensen73110

iTrader: (4)

A good example of how far we've come.
But, also a reminder to keep things in perspective. An '85 Passat 1.8L had 89 hp.

jermdm

I've always liked the TPI intake design. Looks cool as hell. Toss that in with a cool looking car and you got something unique. I'm not interested in making tons of power with a TPI. I just like having it the way it was meant to be. This motor was top of the line in its day. Everybody wants to compare it with todays technology or with what came after TPI's. Have to remember that computer controlled engines were still in its infancy at the time when this motor came out so there's been alot of trial an error since then with new block, intake, exhaust, and computer designs. Who knows, maybe the LT1 and LS motors will be talked bad about in 20 years. I always hear about the thirdgen TPI's being bad. What about the corvette TPI's? Didnt they use the same intake and runners and be limited to the same #'s?

58mark

iTrader: (3)

The TPI is the best looking engine GM ever designed. here's one in a friends 58 impala. Sure, taking out the 348 caused the value of the car to plummet, but he loves driving the car now

hondastyle

I don't know. The intake is too tall and too weird for my own taste. I would prefer something with a little more curve and compact rather then pushing that intake so far out and away.

Podium

iTrader: (2)

My moms passat was an 01 . It was no match from the 305 tpi in terms of power on papaer, but it had no problem pulling it.

Tpi is crap if you wanna go fast

cuisinartvette

The LT5 is like a TPI thats shorter wider and flattened out
Like a spider that got stepped on. neat looking.

On the HSR....Id keep that over the FIRST just port it.
Think the HSR will still make more overall power. Sure the FIRST will extend the band and make great torque BUT-
I believe they are 1.75 also out of the box. I am supposed to get one anyday the guy wants it taken out to 1.9 all the way through. I dont think its possible without cutting the runners in half but we will see.

Black88Z

That's another reason tpi's are knocked, people with 305s racing them lol the 350 is decent, but of course has its limitations, especiall stock. But I've ridden in a 305 (I give you that I didn't actually drive it but the guy that owned it ran it hard) and it wasn't very impressive. Stock 305 tpi. It did burnouts, but obviously nothing like my 350 could do. I'm not trying to offend anyone with a 305 by any means, if I did, sorry. But a lot of people don't look at 350s and 305s differently, to them its just a v8. So if the 305 gets beaten they say, yea my civic beat that camaro. Just saying the 305 isn't exactly thee ideal c.I motor to be racing with lol. To me, I don't bother with anything less than 350. This car will probably stay 350, but my next car will be either 383 or 400 at minimum.if I can find a 454 ill go that way. Again, didn't mean to offend anyone, hopefully I didn't but if I did, sorry.

But the tpi is pretty cool looking, I admit that. I like carbbed tho, to me carbed is "old school" and a lot of people are facinated when they see a carbed engine. The first looks good too, but imho the hsr and lt1 intakes are boring and ugly, no "appeal" to them whatsoever. To me though, if it goes fast that's all that really matters lol

InfernalVortex

iTrader: (4)

The difference between the tpi 305 and tpi 350 is only like 25hp or so depending on the year. Theres not a huge difference there, but the 305 will spin higher and not get choked so soon. Still, the intakes flowed the same amount of air. I bet a 305 tpi g92 t5 car would make you reconsider. The vast majority of the 305 camaros were gm sacrificial lambs to appease the cafe regulators and keep average fuel mileage high. Crappy gears and tiny cams. Find a well optioned 305 tpi g92 car that got the l98 cam and decent gearing and it will give an l98 car a real close run. The t5 cars were only around .1 slower in the 1/4 mile. Nearly identical performance to the l98 cars.

Orr89RocZ

iTrader: (20)

Thats what the specs say but i havent heard or seen a 305 tpi g92 car run 13's with mild bolt ons let alone 12's like L98's can do with aftermarket non tpi intakes

IROCZ1989

iTrader: (1)

Ok, but if your saying the only difference is 25hp or so. Then searxh that thread, the gains on putting just that intake on a bone stock 350 netted an additional 25hp , didnt see the tq numbers. So now were at 50 hp difference give or take with a peanut cam. The main theme of this thread is why people **** on tpis. Companies have introduced runners and baseplates, offered porting and welding techniques. Lingenfelter even went so far to redesign the whole runner plenum concept. Tpis made an intake simaler to the lts design. The inherent flaw to the tpi is long runners , small diameter,no matter how much you port them and weld them , even after market units the outcome is limited. Super rams runners shorten the length considerably, using the same wave tuning concept of tpi torque. The First although not as short as the super ram does shorten up a little more than stock. Long runners are not a death knell to a motor, look at the lsx motors. Gm went from extreme(tpi) to other extreme(lt1) to lsx which is in the middle. By far of all the intakes the super ram gets it right for its time. But this first intake is in a league of its own compared to tpi upgrading. A extrude honed super ram cannot touch the cfm of this system out of the box, let alone of you port it. It has its place, but the stock tpi is very restrictive factory. But a very good designed system.

IROCZ1989

iTrader: (1)

Orr, if im not mistaken I think G92 car is a 1LE option camaro. If so I bet ill never see one on the road. Ive only seen one in my life and it was sitting in someones garage. Is this the g92 option? Maybe someome ca clear this up.

Mortorq

I can't take credit for this quote..."TPI's-the best truck engines GM ever made."

I sure wish Chevy had put some kind of a better LT1-type manifold on by '88 or so.

TBI's are even more sad, I know.

sofakingdom

iTrader: (1)

G92 is actully a "gear" option; got an upgraded rear gear. But, it (AFAIK) required that the car have the dual cats, and in the case of the 305, it got the better cam instead of the peanut (TBI) cam. Which is why those cars are SO MUCH better than the plain-jane 305/auto TPI cars; 3.2x instead of 2.7x for auto G92s or 3.4x instead of 3.08 for stick ones, PLUS better exhaust, PLUS better cam, is a significant wallop.

If memory serves, the MiniRam came out long before the LT1. Which is kinda odd; that's a REALLY SIMPLE design, less "rocket science" even than TPI's acoustic effects. Just yerbasic straight-ahead FLOW. If GM had put a distributor-equipped version of THAT on the 350 instead of the lame TPI for the last 4 or 5 years or so of TPI's run in the market, that segment would probably not be dominated by Frod the way it has been for the last 25 years. Sickening.

Orr89RocZ

iTrader: (20)

Agreed, miniram or hsr swapped L98 is a significantly quicker car than stock tpi. Several tenths shaved off, car or 2 lengths in 1/4 mile. The tpi torque rush goes away but pulls way harder past 4000 to 5200 rpm. Gm could have easily done that or similar but the history of it designed for a 305 must have prevented any thoughts of short runners.

I would have to assume the success of miniram intakes helped develop the lt1 intake

hondastyle

Just as a side question I know it wasn't long lived in the camaro/firebird but how on just a pure intake manifold side of things does the CFI manifold compared to the stock TPI manifold?

IROCgiraffe

iTrader: (3)

With all this talk about how bad the TPI's are.... Can you get any decent performance out of them for little money? I have the 305 TPI mated to the 700R, and I would love to wake it up a bit. My engine appears rather healthy, as in it doesn't leak or burn any oil. I was thinking about upgrading the cam, replacing the stock manifolds with a pair of short or long tube headers and tinkering with the exhaust. This car isn't a daily driver, only a "weekend warrior".

Leaving the TPI intake setup on there as is, what else can be done to increase the breathing of this engine.... replacing the heads or have the stock units worked over a bit?

Thank guys...