jon1all

Just what are the actual factory advertised HP and TQ ratings (and at what RPM) of the non-3.07-equipped L98 in 1988? I've found all of the following on various Corvette sites:

240HP @ 4000RPM / 340TQ @ 3200RPM

240HP @ 4300RPM / 340TQ @ 3200RPM

240HP @ 4000RPM / 345TQ @ 3200RPM

240HP @ 4300RPM / 345TQ @ 3200RPM

240HP @ 4000RPM / 335TQ @ 3200RPM

240HP @ 4300RPM / 335TQ @ 3200RPM

It's maddening! Exactly which is correct? I suspect the first one... but I don't know.

Aardwolf

From what I've read it's 245 HP at 4300, the extra 5 from a less restrictive muffler. I think the verts that year didn't get that and had 240. 340 at 3200 is right.

RetiredSFC 97

http://auto.howstuffworks.com/1988-corvette1.htm

65Z01

My 1988 Chevy Corvette sales lit lists the power on coupe with 2.59 gears and on all convertables as:
240 HP @4,000 RPM
335 lb-ft Torque @3,200 RPM

The coupe with manual tranny and 3.07 gears came with a slight power boost:
245 HP @4,300 RPM
340 lb-ft Torque @3,200 RPM

jon1all

Okay thanks... that is the first official Chevy-sourced numbers I have seen. Where do all these other versions come from I wonder?

I figured the 2.59s would be 240HP @ 4000RPM / 340TQ @ 3200RPM because that's the number I always see advertised for 1987 and it seemed logical that the numbers in 1988 would be the same with the exception of the added 5HP for the 3.07 equipped cars in 88.

Anyone know why they lost the 5 lbs/ft of TQ in 88 (ie, from 340 to 335 for the 2.59 equipped and convertibles)???? Or are the 87 numbers wrong too (ie, are they really 335TQ too)?

RetiredSFC 97

I don't think you will ever find any numbers where they all agree.

A dyno is the only way to tell what your car is doing. I could take 5 brand new cars coming off the assembly line and I could get five different readings I would bet.

BADDUCK

Plus those tiny variations just don't matter.

engle1147

I think your splitting hairs here with the numbers but from what I've read over the years the early version (87-89) is non advertised ~ 290HP, at the crank, without all the belt driven accessories (AC, water pump, smog, power steering) and what not. The advertised hp/torque numbers are with all the crap installed. advertised HP/ Torque numbers may vary as parasitic drivetrain forces are different with the installation of a manual or automatic transmissions....just as CF member 65Z01 suggests.

milsurpman

Anyone know why they lost the 5 lbs/ft of TQ in 88 (ie, from 340 to 335 for the 2.59 equipped and convertibles)???? Or are the 87 numbers wrong too (ie, are they really 335TQ too)?[/QUOTE]

If you still have the stock mufflers the easy way to tell is the sport mufflers are equipped with 2 functional outlets. The 240 hp model has one functional outlet. The different rating between 87 and 88 appears to mainly be due to extra drag on the accessory drive due to the infamous serpentine drive damper attached to the front of the water pump pulley. It actually eats a surprising amount of power. It was used to dampen out air conditioning on off vibes with the new for 88 nippodenso compressor.

pologreen1

either way NOT ENOUGH

jon1all

Thanks guys… so it’s all the “frisbee’s” fault, eh? That makes sense actually.

BTW… understand that I didn’t ask this because I am that overly concerned about 5 lbs/ft of torque here or a couple hundred RPM of peak horsepower there… it’s just that there was some many different versions of the numbers for 1988 that the OCD in me just screamed foul! Didn’t care what the correct numbers were per se… just knew they couldn’t all be correct. And just wanted to know what Chevy really advertised back in 88… and it sounds like 240HP @ 4000RPM & 335TQ @ 3200RPM is the answer.

RetiredSFC 97

65Z01

Indeed I've heard that the 5chp difference was due to less restrictive exhaust.

Yep, the frisbee does suck up 10chp; toss it if you have no belt squeal on A/C kick in without it.

jon1all

Is there any special trick to getting the frisbee off? It looks like you just un bolt it, but will anything else come off by accident with it? IOW, any pitfalls I should be aware of before I go removing it? Thx!

engle1147

Loosen the bolts slightly then remove the "S" belt. With the belt off finish unbolting the frisbee and then see how far you can throw it....leaving out the frisbee reverse the order for installation. Before you crank the engine check the backside of the water pump flange where the bolts normally exit to make sure the bolts are not sticking through too far to hit anything...you should not have any complications though if remember correctly.

BADDUCK

Put some dual outlet muffs and March aluminum U D pulleys and you can pick up some power. When you pull the frisbee put some washers on the bolts to make sure they don't bottom out when you reinstall.